origin of humans essay

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Human evolution evidence.

Evidence of Evolution

Scientists have discovered a wealth of evidence concerning human evolution, and this evidence comes in many forms. Thousands of human fossils enable researchers and students to study the changes that occurred in brain and body size, locomotion, diet, and other aspects regarding the way of life of early human species over the past 6 million years. Millions of stone tools, figurines and paintings, footprints, and other traces of human behavior in the prehistoric record tell about where and how early humans lived and when certain technological innovations were invented. Study of human genetics show how closely related we are to other primates – in fact, how connected we are with all other organisms – and can indicate the prehistoric migrations of our species, Homo sapiens , all over the world. Advances in the dating of fossils and artifacts help determine the age of those remains, which contributes to the big picture of when different milestones in becoming human evolved.

Exciting scientific discoveries continually add to the broader and deeper public knowledge of human evolution. Find out about the latest evidence in our What’s Hot in Human Origins section.

Explore the evidence of early human behavior—from ancient footprints to stone tools and the earliest symbols and art – along with similarities and differences in the behavior of other primate species.

Human Fossils

From skeletons to teeth, early human fossils have been found of more than 6,000 individuals. Look into our digital 3-D collection and learn about fossil human species.

3D Collection

Explore our 3D collection of fossils, artifacts, primates, and other animals.

Our genes offer evidence of how closely we are related to one another – and of our species’ connection with all other organisms.

As plants and animals die, their remains are sometimes preserved in Earth’s rock record as fossils.

Human Evolution Interactive Timeline

Explore the evidence for human evolution in this interactive timeline - climate change, species, and milestones in becoming human.

Zoom in using the magnifier on the bottom for a closer look! This interactive is no longer in FLASH , it may take a moment to load.

• Human Family Tree

The human family tree shows the various species that constitute the human evolutionary family.

Snapshots in Time

In these video interactives, put together clues and explore discoveries the prehistoric sites of Swartkrans, South Africa, Olorgesailie, Kenya, and  Shanidar Cave, Iraq.

• Climate Effects on Human Evolution
• Survival of the Adaptable
• Human Evolution Timeline Interactive
• 2011 Olorgesailie Dispatches
• 2004 Olorgesailie Dispatches
• 1999 Olorgesailie Dispatches
• Olorgesailie Drilling Project
• Kanam, Kenya
• Kanjera, Kenya
• Ol Pejeta, Kenya
• Olorgesailie, Kenya
• Evolution of Human Innovation
• Adventures in the Rift Valley: Interactive
• 'Hobbits' on Flores, Indonesia
• Earliest Humans in China
• Bose, China
• Anthropocene: The Age of Humans
• Fossil Forensics: Interactive
• What's Hot in Human Origins?
• Instructions
• Carnivore Dentition
• Ungulate Dentition
• Primate Behavior
• Footprints from Koobi Fora, Kenya
• Laetoli Footprint Trails
• Footprints from Engare Sero, Tanzania
• Hammerstone from Majuangou, China
• Handaxe and Tektites from Bose, China
• Handaxe from Europe
• Handaxe from India
• Oldowan Tools from Lokalalei, Kenya
• Olduvai Chopper
• Stone Tools from Majuangou, China
• Middle Stone Age Tools
• Burin from Laugerie Haute & Basse, Dordogne, France
• La Madeleine, Dordogne, France
• Butchered Animal Bones from Gona, Ethiopia
• Katanda Bone Harpoon Point
• Oldest Wooden Spear
• Punctured Horse Shoulder Blade
• Stone Sickle Blades
• Projectile Point
• Oldest Pottery
• Pottery Fragment
• Fire-Altered Stone Tools
• Terra Amata Shelter
• Qafzeh: Oldest Intentional Burial
• Assyrian Cylinder Seal
• Blombos Ocher Plaque
• Ishango Bone
• Bone and Ivory Needles
• Carved Ivory Running Lion
• Female torso in ivory
• Ivory Horse Figurine
• Ivory Horse Sculpture
• Lady of Brassempouy
• Lion-Man Figurine
• Willendorf Venus
• Ancient Shell Beads
• Carved Bone Disc
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• Oldest Known Shell Beads
• Ancient Flute
• Ancient Pigments
• Apollo 11 Plaque
• Carved antler baton with horses
• Geometric incised bone rectangle
• Tata Plaque
• Mystery Skull Interactive
• Shanidar 3 - Neanderthal Skeleton
• One Species, Living Worldwide
• Human Skin Color Variation
• Ancient DNA and Neanderthals
• Swartkrans, South Africa
• Shanidar, Iraq
• Walking Upright
• Tools & Food
• Social Life
• Language & Symbols
• Humans Change the World
• Introduction to Human Evolution
• Nuts and bolts classification: Arbitrary or not? (Grades 6-8)
• The Origins and Evolution of Human Bipedality (Grades 9-12)
• Comparison of Human and Chimp Chromosomes (Grades 9-12)
• Hominid Cranial Comparison: The "Skulls" Lab (Grades 9-12)
• Investigating Common Descent: Formulating Explanations and Models (Grades 9-12)
• Fossil and Migration Patterns in Early Hominids (Grades 9-12)
• For College Students
• Why do we get goose bumps?
• Chickens, chimpanzees, and you - what do they have in common?
• Grandparents are unique to humans
• How strong are we?
• Humans are handy!
• Humans: the running ape
• Our big hungry brain!
• Our eyes say it!
• The early human tool kit
• The short-haired human!
• The “Nutcracker”
• What can lice tell us about human evolution?
• What does gut got to do with it?
• Why do paleoanthropologists love Lucy?
• Why do we have wisdom teeth?
• Human Origins Glossary
• Teaching Evolution through Human Examples
• Frequently Asked Questions
• Recommended Books
• Exhibit Floorplan Interactive
• Print Floorplan PDF
• Reconstructions of Early Humans
• Chesterfield County Public Library
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• Human Origins Do it Yourself Exhibit
• Exhibit Field Trip Guide
• Acknowledgments
• Human Origins Program Team
• Connie Bertka
• Betty Holley
• Nancy Howell
• Lee Meadows
• Jamie L. Jensen
• David Orenstein
• Michael Tenneson
• Leonisa Ardizzone
• David Haberman
• Fred Edwords (Emeritus)
• Elliot Dorff (Emeritus)
• Francisca Cho (Emeritus)
• Peter F. Ryan (Emeritus)
• Mustansir Mir (Emeritus)
• Randy Isaac (Emeritus)
• Mary Evelyn Tucker (Emeritus)
• Wentzel van Huyssteen (Emeritus)
• Joe Watkins (Emeritus)
• Tom Weinandy (Emeritus)
• Members Thoughts on Science, Religion & Human Origins (video)
• Science, Religion, Evolution and Creationism: Primer
• The Evolution of Religious Belief: Seeking Deep Evolutionary Roots
• Laboring for Science, Laboring for Souls:  Obstacles and Approaches to Teaching and Learning Evolution in the Southeastern United States
• Public Event : Religious Audiences and the Topic of Evolution: Lessons from the Classroom (video)
• Evolution and the Anthropocene: Science, Religion, and the Human Future
• Imagining the Human Future: Ethics for the Anthropocene
• Human Evolution and Religion: Questions and Conversations from the Hall of Human Origins
• I Came from Where? Approaching the Science of Human Origins from Religious Perspectives
• Religious Perspectives on the Science of Human Origins
• Submit Your Response to "What Does It Mean To Be Human?"
• Volunteer Opportunities
• Submit Question
• "Shaping Humanity: How Science, Art, and Imagination Help Us Understand Our Origins" (book by John Gurche)
• What Does It Mean To Be Human? (book by Richard Potts and Chris Sloan)
• Bronze Statues
• Reconstructed Faces

Introductory essay

Written by the educator who created What Makes Us Human?, a brief look at the key facts, tough questions and big ideas in his field. Begin this TED Study with a fascinating read that gives context and clarity to the material.

As a biological anthropologist, I never liked drawing sharp distinctions between human and non-human. Such boundaries make little evolutionary sense, as they ignore or grossly underestimate what we humans have in common with our ancestors and other primates. What's more, it's impossible to make sharp distinctions between human and non-human in the paleoanthropological record. Even with a time machine, we couldn't go back to identify one generation of humans and say that the previous generation contained none: one's biological parents, by definition, must be in the same species as their offspring. This notion of continuity is inherent to most evolutionary perspectives and it's reflected in the similarities (homologies) shared among very different species. As a result, I've always been more interested in what makes us similar to, not different from, non-humans.

Evolutionary research has clearly revealed that we share great biological continuity with others in the animal kingdom. Yet humans are truly unique in ways that have not only shaped our own evolution, but have altered the entire planet. Despite great continuity and similarity with our fellow primates, our biocultural evolution has produced significant, profound discontinuities in how we interact with each other and in our environment, where no precedent exists in other animals. Although we share similar underlying evolved traits with other species, we also display uses of those traits that are so novel and extraordinary that they often make us forget about our commonalities. Preparing a twig to fish for termites may seem comparable to preparing a stone to produce a sharp flake—but landing on the moon and being able to return to tell the story is truly out of this non-human world.

Humans are the sole hominin species in existence today. Thus, it's easier than it would have been in the ancient past to distinguish ourselves from our closest living relatives in the animal kingdom. Primatologists such as Jane Goodall and Frans de Waal, however, continue to clarify why the lines dividing human from non-human aren't as distinct as we might think. Goodall's classic observations of chimpanzee behaviors like tool use, warfare and even cannibalism demolished once-cherished views of what separates us from other primates. de Waal has done exceptional work illustrating some continuity in reciprocity and fairness, and in empathy and compassion, with other species. With evolution, it seems, we are always standing on the shoulders of others, our common ancestors.

Primatology—the study of living primates—is only one of several approaches that biological anthropologists use to understand what makes us human. Two others, paleoanthropology (which studies human origins through the fossil record) and molecular anthropology (which studies human origins through genetic analysis), also yield some surprising insights about our hominin relatives. For example, Zeresenay Alemsegad's painstaking field work and analysis of Selam, a 3.3 million-year old fossil of a 3-year-old australopithecine infant from Ethiopia, exemplifies how paleoanthropologists can blur boundaries between living humans and apes.

Selam, if alive today, would not be confused with a three-year-old human—but neither would we mistake her for a living ape. Selam's chimpanzee-like hyoid bone suggests a more ape-like form of vocal communication, rather than human language capability. Overall, she would look chimp-like in many respects—until she walked past you on two feet. In addition, based on Selam's brain development, Alemseged theorizes that Selam and her contemporaries experienced a human-like extended childhood with a complex social organization.

Fast-forward to the time when Neanderthals lived, about 130,000 – 30,000 years ago, and most paleoanthropologists would agree that language capacity among the Neanderthals was far more human-like than ape-like; in the Neanderthal fossil record, hyoids and other possible evidence of language can be found. Moreover, paleogeneticist Svante Pääbo's groundbreaking research in molecular anthropology strongly suggests that Neanderthals interbred with modern humans. Paabo's work informs our genetic understanding of relationships to ancient hominins in ways that one could hardly imagine not long ago—by extracting and comparing DNA from fossils comprised largely of rock in the shape of bones and teeth—and emphasizes the great biological continuity we see, not only within our own species, but with other hominins sometimes classified as different species.

Though genetics has made truly astounding and vital contributions toward biological anthropology by this work, it's important to acknowledge the equally pivotal role paleoanthropology continues to play in its tandem effort to flesh out humanity's roots. Paleoanthropologists like Alemsegad draw on every available source of information to both physically reconstruct hominin bodies and, perhaps more importantly, develop our understanding of how they may have lived, communicated, sustained themselves, and interacted with their environment and with each other. The work of Pääbo and others in his field offers powerful affirmations of paleoanthropological studies that have long investigated the contributions of Neanderthals and other hominins to the lineage of modern humans. Importantly, without paleoanthropology, the continued discovery and recovery of fossil specimens to later undergo genetic analysis would be greatly diminished.

Molecular anthropology and paleoanthropology, though often at odds with each other in the past regarding modern human evolution, now seem to be working together to chip away at theories that portray Neanderthals as inferior offshoots of humanity. Molecular anthropologists and paleoanthropologists also concur that that human evolution did not occur in ladder-like form, with one species leading to the next. Instead, the fossil evidence clearly reveals an evolutionary bush, with numerous hominin species existing at the same time and interacting through migration, some leading to modern humans and others going extinct.

Molecular anthropologist Spencer Wells uses DNA analysis to understand how our biological diversity correlates with ancient migration patterns from Africa into other continents. The study of our genetic evolution reveals that as humans migrated from Africa to all continents of the globe, they developed biological and cultural adaptations that allowed for survival in a variety of new environments. One example is skin color. Biological anthropologist Nina Jablonski uses satellite data to investigate the evolution of skin color, an aspect of human biological variation carrying tremendous social consequences. Jablonski underscores the importance of trying to understand skin color as a single trait affected by natural selection with its own evolutionary history and pressures, not as a tool to grouping humans into artificial races.

For Pääbo, Wells, Jablonski and others, technology affords the chance to investigate our origins in exciting new ways, adding pieces into the human puzzle at a record pace. At the same time, our technologies may well be changing who we are as a species and propelling us into an era of "neo-evolution."

Increasingly over time, human adaptations have been less related to predators, resources, or natural disasters, and more related to environmental and social pressures produced by other humans. Indeed, biological anthropologists have no choice but to consider the cultural components related to human evolutionary changes over time. Hominins have been constructing their own niches for a very long time, and when we make significant changes (such as agricultural subsistence), we must adapt to those changes. Classic examples of this include increases in sickle-cell anemia in new malarial environments, and greater lactose tolerance in regions with a long history of dairy farming.

Today we can, in some ways, evolve ourselves. We can enact biological change through genetic engineering, which operates at an astonishing pace in comparison to natural selection. Medical ethicist Harvey Fineberg calls this "neo-evolution". Fineberg goes beyond asking who we are as a species, to ask who we want to become and what genes we want our offspring to inherit. Depending on one's point of view, the future he envisions is both tantalizing and frightening: to some, it shows the promise of science to eradicate genetic abnormalities, while for others it raises the specter of eugenics. It's also worth remembering that while we may have the potential to influence certain genetic predispositions, changes in genotypes do not guarantee the desired results. Environmental and social pressures like pollution, nutrition or discrimination can trigger "epigenetic" changes which can turn genes on or off, or make them less or more active. This is important to factor in as we consider possible medical benefits from efforts in self-directed evolution. We must also ask: In an era of human-engineered, rapid-rate neo-evolution, who decides what the new human blueprints should be?

Technology figures in our evolutionary future in other ways as well. According to anthropologist Amber Case, many of our modern technologies are changing us into cyborgs: our smart phones, tablets and other tools are "exogenous components" that afford us astonishing and unsettling capabilities. They allow us to travel instantly through time and space and to create second, "digital selves" that represent our "analog selves" and interact with others in virtual environments. This has psychological implications for our analog selves that worry Case: a loss of mental reflection, the "ambient intimacy" of knowing that we can connect to anyone we want to at any time, and the "panic architecture" of managing endless information across multiple devices in virtual and real-world environments.

Despite her concerns, Case believes that our technological future is essentially positive. She suggests that at a fundamental level, much of this technology is focused on the basic concerns all humans share: who am I, where and how do I fit in, what do others think of me, who can I trust, who should I fear? Indeed, I would argue that we've evolved to be obsessed with what other humans are thinking—to be mind-readers in a sense—in a way that most would agree is uniquely human. For even though a baboon can assess those baboons it fears and those it can dominate, it cannot say something to a second baboon about a third baboon in order to trick that baboon into telling a fourth baboon to gang up on a fifth baboon. I think Facebook is a brilliant example of tapping into our evolved human psychology. We can have friends we've never met and let them know who we think we are—while we hope they like us and we try to assess what they're actually thinking and if they can be trusted. It's as if technology has provided an online supply of an addictive drug for a social mind evolved to crave that specific stimulant!

Yet our heightened concern for fairness in reciprocal relationships, in combination with our elevated sense of empathy and compassion, have led to something far greater than online chats: humanism itself. As Jane Goodall notes, chimps and baboons cannot rally together to save themselves from extinction; instead, they must rely on what she references as the "indomitable human spirit" to lessen harm done to the planet and all the living things that share it. As Goodall and other TED speakers in this course ask: will we use our highly evolved capabilities to secure a better future for ourselves and other species?

I hope those reading this essay, watching the TED Talks, and further exploring evolutionary perspectives on what makes us human, will view the continuities and discontinuities of our species as cause for celebration and less discrimination. Our social dependency and our prosocial need to identify ourselves, our friends, and our foes make us human. As a species, we clearly have major relationship problems, ranging from personal to global scales. Yet whenever we expand our levels of compassion and understanding, whenever we increase our feelings of empathy across cultural and even species boundaries, we benefit individually and as a species.

Get started

Zeresenay Alemseged

The search for humanity's roots, relevant talks.

We are all cyborgs now

Frans de Waal

Moral behavior in animals.

Harvey Fineberg

Are we ready for neo-evolution.

Jane Goodall

What separates us from chimpanzees.

Nina Jablonski

Skin color is an illusion.

Spencer Wells

A family tree for humanity.

Svante Pääbo

Dna clues to our inner neanderthal.

How Africa Became the Cradle of Humankind

A fossil discovery in 1924 revolutionized the search for human ancestors, leading scientists to Africa

Erin Wayman

If you know anything about human evolution, it’s probably that humans arose in Africa. But you may not know how scientists came to that conclusion. It’s one of my favorite stories in the history of paleoanthropology—one that involves an anatomist you’ve probably never heard of and an infant who was attacked by an eagle and dropped into a hole almost three million years ago.

The idea that humans evolved in Africa can be traced to Charles Darwin. In his 1871 book The Descent of Man , Darwin speculated that it was “probable” that Africa was the cradle of humans because our two closest living relatives—chimpanzees and gorillas—live there. However, he also noted, a large, extinct ape once lived in Europe millions of years ago, leaving plenty of time for our earliest ancestors to migrate to Africa. So, he concluded, “it’s useless to speculate on the subject.”

By the early 20th century, the world’s leading anatomists thought they knew the answer: Humans evolved somewhere in Europe or Asia. By then, Neanderthals had been found in Europe; Java Man (now known as Homo erectus ) had been discovered in Indonesia and Piltdown Man ( later exposed as a hoax ) had been unearthed in England. Although these ancient beings were primitive, they clearly resembled modern humans.

In 1924, a fossil discovery in South Africa challenged this view of a Eurasian homeland and revolutionized the study of human evolution.

Raymond Dart, an Australian-born anatomist working at the University of Witwatersrand in Johannesburg, was interested in fossils. In the fall of 1924, as Dart was preparing to attend a wedding, two boxes of rocks blasted from a limestone quarry near the town of Taung were delivered at his house. Over the objections of his wife, Dart, dressed in formal wear, dug into one of the boxes. He found something amazing: the fossilized mold of a brain.

This was a special brain. The shape and folds on the brain’s surface implied it belonged to some kind of human—perhaps an ancient human ancestor, Dart thought. Further digging led Dart to another rock that the brain fit perfectly into. After months of careful chipping, Dart freed the brain’s corresponding face and lower jaw on December 23. “I doubt if there was any parent prouder of his offspring,” Dart later wrote in his 1959 book Adventures with the Missing Link , “on that Christmas of 1924.”

It was probably the best Christmas present a paleoanthropologist could ever receive. The creature’s baby teeth revealed that it was a child (probably 3 or 4 years old, scientists now think). Other features of the so-called Taung Child confirmed Dart’s suspicion that he was handling a human ancestor. Although the being looked apish in many ways, the face lacked a pronounced muzzle as seen in chimps and gorillas. And the placement of the hole through which the spinal cord exits the bottom of the skull—the foramen magnum —suggested the Taung Child had an erect posture and walked upright on two legs (animals that travel on four legs, such as chimps and gorillas, have a foramen magnum more toward the back of the skull).

Dart wasted no time in reporting his results, announcing in early February 1925, in the journal Nature , that he had found “an extinct race of apes intermediate between living anthropoids and man .” He named it Australopithecus africanus (“Southern Ape of Africa”).

Australopithecus africanus did not receive a warm welcome from experts in the field. In the minds of most academics, there was a lot to criticize. Many derided Dart for rushing to publication, and media hoopla surrounding the announcement—before experts had a chance to take a close look at the finding—irked more established anatomists. Researchers even ridiculed Dart for mixing Latin and Greek when inventing the name “Australopithecus.”

The biggest problems were scientific. No one had any idea what the Taung Child would have looked like as an adult. Furthermore, in addition to being from the wrong continent, the fossil was too ape-like to fit the early-20th-century view of human evolution. At the time, fossils like Piltdown Man indicated the earliest humans evolved big brains before other aspects of modern human physiology emerged—even before the ability to walk upright. Thus, experts dismissed the Taung fossil as just an old ape.

But at least one person thought Dart was right. Paleontologist Robert Broom took up Dart’s cause. While investigating several limestone caves in South Africa during the 1930s and 1940s, Broom discovered numerous fossils of adult “ape-men” specimens that looked similar to Dart’s Taung Child. The mounting evidence—plus the uncovering of the Piltdown Hoax in the late 1940s and early 1950s—convinced even the most ardent skeptics that australopithecines belonged in the human family, and that Africa was the birthplace of humans. The work dramatically altered the trajectory of human evolution studies, changing where people looked for human fossils and what they expected to find.

Not all of Dart’s ideas have stood the test of time, however. As fossils of australopithecines were uncovered in South African caves, Dart noticed they were always found in association with animal parts—particularly the teeth, jaws and horns of hoofed animals. Dart believed these were the remains of an “osteodontokeratic” (bone, tooth and horn) culture, in which early humans used these broken bits as tools for warfare and hunting. Scientists later realized that predators such as leopards had accumulated the heaps of bones. In fact, holes on the Taung Child reveal it was the victim of a hungry eagle that dropped part of its meal into the entrance of the cave where the fossil was eventually found.

I never get tired of the story of Raymond Dart, in part because the Taung Child is kind of an adorable fossil. But mostly it’s because Dart’s work is a great reminder that nothing in human evolution is written in stone; you have to keep an open mind.

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Erin Wayman | | READ MORE

Erin Wayman is a science and human evolution blogger for Hominid Hunting. She has M.As in biological anthropology and science writing.

• NALEDI FOSSILS

12 Theories of How We Became Human, and Why They’re All Wrong

Killers? Hippies? Toolmakers? Chefs? Scientists have trouble agreeing on the essence of humanity—and when and how we acquired it.

What a piece of work is man! Everyone agrees on that much. But what exactly is it about Homo sapiens that makes us unique among animals, let alone apes, and when and how did our ancestors acquire that certain something? The past century has seen a profusion of theories. Some reveal as much about the time their proponents lived in as they do about human evolution.

1. We Make Tools: “It is in making tools that man is unique,” anthropologist Kenneth Oakley wrote in a 1944 article . Apes use found objects as tools, he explained, “but the shaping of sticks and stones to particular uses was the first recognizably human activity.” In the early 1960s, Louis Leakey attributed the dawn of toolmaking, and thus of humanity, to a species named Homo habilis (“Handy Man”), which lived in East Africa around 2.8 million years ago. But as Jane Goodall and other researchers have since shown, chimps also shape sticks for particular uses—stripping them of their leaves, for instance, to “fish” for underground insects. Even crows, which lack hands, are pretty handy.

This primitive hand ax, found at a site in Israel, dates from 790,000 years ago and was probably made by Homo erectus. The oldest stone tools are 3.3 million years old.

2. We’re Killers : According to anthropologist Raymond Dart, our predecessors differed from living apes in being confirmed killers—carnivorous creatures that "seized living quarries by violence, battered them to death, tore apart their broken bodies, dismembered them limb from limb, slaking their ravenous thirst with the hot blood of victims and greedily devouring livid writhing flesh.” It may read like pulp fiction now, but after the horrific carnage of the Second World War, Dart’s 1953 article outlining his “killer ape” theory struck a chord.

Raymond Dart, originator of the “killer ape” theory of human evolution, holds the skull of the Taung Child, the first australopithecine ever discovered.

3. We Share Food : In the 1960s, the killer ape gave way to the hippie ape. Anthropologist Glynn Isaac unearthed evidence of animal carcasses that had been purposefully moved from the sites of their deaths to locations where, presumably, the meat could be shared with the whole commune. As Isaac saw it, food sharing led to the need to share information about where food could be found—and thus to the development of language and other distinctively human social behaviors.

4. We Swim in the Nude : A little later in the age of Aquarius, Elaine Morgan , a TV documentary writer, claimed that humans are so different from other primates because our ancestors evolved in a different environment—near and in the water. Shedding body hair made them faster swimmers, while standing upright enabled them to wade. The “aquatic ape” hypothesis is widely dismissed by the scientific community. But, in 2013, David Attenborough endorsed it.

5. We Throw Stuff : Archaeologist Reid Ferring believes our ancestors began to man up when they developed the ability to hurl stones at high velocities . At Dmanisi , a 1.8- million-year-old hominin site in the former Soviet republic of Georgia, Ferring found evidence that Homo erectus invented public stonings to drive predators away from their kills. “The Dmanisi people were small,” says Ferring.“This place was filled with big cats. So how did hominins survive? How did they make it all the way from Africa? Rock throwing offers part of the answer.” Stoning animals also socialized us, he argues, because it required a group effort to be successful.

This painting inspired by archaeological finds at Dmanisi, in the Republic of Georgia, shows a female Homo erectus preparing to throw a stone to drive hyenas away from a deer carcass.

6. We Hunt : Hunting did much more than inspire cooperation, anthropologists Sherwood Washburn and C. S. Lancaster argued in a 1968 paper : “In a very real sense our intellect, interests, emotions and basic social life—all are evolutionary products of the success of the hunting adaptation.” Our larger brains, for instance, developed out of the need to store more information about where and when to find game. Hunting also allegedly led to a division of labor between the sexes, with women doing the foraging. Which raises the question: Why do women have big brains too?

7. We Trade Food for Sex : More specifically, monogamous sex. The crucial turning point in human evolution, according to a theory published in 1981 by C. Owen Lovejoy, was the emergence of monogamy six million years ago. Until then, brutish alpha males who drove off rival suitors had the most sex. Monogamous females, however, favored males who were most adept at providing food and sticking around to help raise junior. Our ancestors began walking upright, according to Lovejoy, because it freed up their hands and allowed them to carry home more groceries.

On an elephant that died of natural causes, archaeologists tested how fast they could butcher meat with primitive stone tools. Each man cut a hundred pounds an hour.

8. We Eat (Cooked) Meat : Big brains are hungry—gray matter requires 20 times more energy than muscle does. They could never have evolved on a vegetarian diet, some researchers claim ; instead, our brains grew only once we started eating meat, a food source rich in protein and fat, around two to three million years ago. And according to anthropologist Richard Wrangham , once our ancestors invented cooking—a uniquely human behavior that makes food easier to digest—they wasted less energy chewing or pounding meat and so had even more energy available for their brains. Eventually those brains grew large enough to make the conscious decision to become vegan.

9. We Eat (Cooked) Carbs : Or maybe our bigger brains were made possible by carb-loading, according to a recent paper . Once our ancestors had invented cooking, tubers and other starchy plants became an excellent source of brain food, more readily available than meat. An enzyme in our saliva called amylase helps break down carbohydrates into the glucose the brain needs. Evolutionary geneticist Mark G. Thomas of University College London notes that our DNA contains multiple copies of the gene for amylase, suggesting that it—and tubers—helped fuel the explosive growth of the human brain.

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10. We Walk on Two Feet : Did the crucial turning point in human evolution occur when our ancestors descended from the trees and started walking upright? Proponents of the “savanna hypothesis” say climate change drove that adaptation. As Africa became drier around three million years ago, the forests shrank and savannas came to dominate the landscape. That favored primates who could stand up and see above the tall grasses to watch for predators, and who could travel more efficiently across the open landscape, where food and water sources were far apart. One problem for this hypothesis is the 2009 discovery of Ardipithecus ramidus, a hominid that lived 4.4 million years ago in what’s now Ethiopia. That region was damp and wooded then—yet “Ardi” could walk on two legs.

As the Africa climate became more arid, after about three million years ago, forests gave way to grasslands—and our ancestors had to adapt.

11. We Adapt : Richard Potts , director of the Smithsonian's Human Origins Program, suggests that human evolution was influenced by multiple changes in climate rather than a single trend. The emergence of the Homo lineage nearly three million years ago, he says, coincided with drastic fluctuations between wet and dry climates. Natural selection favored primates that could cope with constant, unpredictable change, Potts argues: Adaptability itself is the defining characteristic of humans.

Projectile weapons made by early Homo sapiens, found at Pinnacle Point in South Africa, reflect the human ability to cooperate, according to anthropologist Curtis Marean.

12. We Unite and Conquer : Anthropologist Curtis Marean offers a vision of human origins well suited to our globalized age: We are the ultimate invasive species . After tens of thousands of years confined to a single continent, our ancestors colonized the globe. How did they accomplish this feat? The key, Marean says, was a genetic predisposition to cooperate—born not from altruism but from conflict. Primate groups that cooperated gained a competitive edge over rival groups, and their genes survived. “The joining of this unique proclivity to our ancestors’ advanced cognitive abilities enabled them to nimbly adapt to new environments,” Marean writes. “It also fostered innovation, giving rise to a game-changing technology: advanced projectile weapons.”

So what’s wrong with all these theories?

Many of them have merit, but they share a bias: the idea that humanity can be defined by a single well-defined trait or group of traits and that a single stage in evolution was a crucial turning point on the inevitable road to Homo sapiens.

But our ancestors weren’t beta tests. They weren’t evolving toward something, they were just surviving as Australopithecus or Homo erectus. And no single trait they acquired was a turning point, because there was never anything inevitable about the outcome: the toolmaking, stone-throwing, meat-and-potato-eating, highly cooperative, adaptable—and oh-so-big-brained—killer ape that is us. And is still evolving now.

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Homo sapiens

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• Smithsonian National Museum of Natiral History - Human Evolution Evidence - Homo Sapien
• Australian Museum - Homo sapiens – modern humans
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• Social Sci LibreTexts - Homo sapiens, our History and our Future
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• National Center for Biotechnology Information - PubMed Central - The origin and evolution of Homo sapiens
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Homo sapiens , the species to which all modern human beings belong. Homo sapiens is one of several species grouped into the genus Homo , but it is the only one that is not extinct . See also human evolution .

The name Homo sapiens was applied in 1758 by the father of modern biological classification ( see taxonomy ), Carolus Linnaeus . It had long been known that human beings physically resemble the primates more closely than any other known living organisms, but at the time it was a daring act to classify human beings within the same framework used for the rest of nature. Linnaeus, concerned exclusively with similarities in bodily structure, faced only the problem of distinguishing H. sapiens from apes ( gorillas , chimpanzees , orangutans , and gibbons ), which differ from humans in numerous bodily as well as cognitive features. ( Charles Darwin’s treatise on evolution , On the Origin of Species , would come 101 years later.)

(Read Ray Kurzweil’sBritannica essay on the future of “Nonbiological Man.”)

Since Linnaeus’s time, a large fossil record has been discovered. This record contains numerous extinct species that are much more closely related to humans than to today’s apes and that were presumably more similar to H. sapiens behaviorally as well. Following the ancestors of modern human beings into the distant past raises the question of what is meant by the word human . H. sapiens is human by definition, whereas apes are not. But what of the extinct members of the human tribe ( Hominini ), who were clearly not H. sapiens but were nonetheless very much like them? There is no definitive answer to this question. Although human evolution can be said to involve all those species more closely related to H. sapiens than to the apes, the adjective human is usually applied only to H. sapiens and other members of the genus Homo (e.g., H. erectus , H. habilis ). Behaviorally, only H. sapiens can be said to be “fully human,” but even the definition of H. sapiens is a matter of active debate. Some paleoanthropologists extend the span of this species far back into time to include many anatomically distinctive fossils that others prefer to allocate to several different extinct species. In contrast, a majority of paleoanthropologists, wishing to bring the study of hominins into line with that of other mammals , prefer to assign to H. sapiens only those fossil forms that fall within the anatomic spectrum of the species as it exists today. In this sense, H. sapiens is very recent, having originated in Africa more than 315,000 years ago (315 kya).

(Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”)

Before about 1980 it was widely thought that distinctively hominin fossils could be identified from 14 to 12 million years ago (mya). However, during the 1970s geneticists introduced the use of molecular clocks to calculate how long species had been separated from a common ancestor. The molecular clock concept is based on an assumed regularity in the accumulation of tiny changes in the genetic codes of humans and other organisms. Use of this concept, together with a reanalysis of the fossil record , moved the estimated time of the evolutionary split between apes and human ancestors forward to as recently as about 5 mya. Since then the molecular data emerging from DNA sequencing and a steady trickle of new hominin fossil finds have pushed the earliest putative hominin ancestry back in time somewhat, to perhaps 8–6 mya.

Essay on Human Evolution

Students are often asked to write an essay on Human Evolution in their schools and colleges. And if you’re also looking for the same, we have created 100-word, 250-word, and 500-word essays on the topic.

Let’s take a look…

100 Words Essay on Human Evolution

Introduction.

Human evolution is the lengthy process of change by which people originated from apelike ancestors. It’s a fascinating journey that took millions of years.

The Beginning

Our story begins in Africa about 6 million years ago. The first humans were primates, similar to apes.

Walking Upright

Around 4 million years ago, early humans started walking upright. This trait, called bipedalism, set us apart from other apes.

Use of Tools

About 2.6 million years ago, humans started using tools. This was a major step in our evolution.

Development of Language

Human evolution is a fascinating subject. It helps us understand where we come from and who we are.

250 Words Essay on Human Evolution

Introduction to human evolution.

Human evolution is an intriguing scientific concept that traces the progression of Homo sapiens from our early ancestors. It is a multidimensional process that has been shaped by natural selection, genetic drift, migration, and mutation over millions of years.

The Early Beginnings

The journey of human evolution began approximately 6 million years ago in Africa, with the emergence of the first hominins, our earliest ancestors. These hominins were distinguished from apes by their upright posture and bipedal locomotion.

The Genus Homo

Around 2 million years ago, the genus Homo appeared, characterized by a significant increase in brain size and the advent of tool use. Homo habilis, Homo erectus, and eventually Homo sapiens, our species, were part of this genus. Homo sapiens are unique in their capacity for complex language, abstract thought, and creativity.

The Role of Environment

Environmental changes played a critical role in human evolution. For instance, climate fluctuations led to the development of traits like bipedalism, which allowed early hominins to adapt to diverse habitats.

Modern Humans and Migration

The story of human evolution is a testament to our species’ adaptability and resilience. It underscores the dynamic interplay between biology and environment, shaping our past and influencing our future. As we continue to unravel the mysteries of our evolution, we gain profound insights into what it means to be human.

500 Words Essay on Human Evolution

Human evolution is a fascinating and complex process that has shaped us into the beings we are today. It is a multidisciplinary field of science that encompasses biology, anthropology, archaeology, and genetics. The process of evolution involves a series of natural changes that cause species to arise, adapt to the environment, and eventually become extinct.

The Origins of Homo Sapiens

Over time, evolutionary pressures such as environmental changes and competition for resources led to the emergence of new hominin species. Around two million years ago, the genus Homo, which includes modern humans, emerged. The Homo species had larger brains and made sophisticated tools.

The Advent of Homo Sapiens

Approximately 300,000 years ago, Homo sapiens, our own species, appeared. Early Homo sapiens had a combination of physical traits from earlier hominin species and new traits that we still possess today, such as a high forehead and a chin. They also exhibited advanced behaviors, such as creating complex tools and engaging in symbolic behavior like art and burial rituals.

Migration and Modern Evolution

The Homo sapiens began to migrate out of Africa around 70,000 years ago, gradually populating the entire globe. They adapted to a variety of environments and developed diverse cultures. This migration and adaptation are reflected in the genetic diversity we see in modern humans.

Modern human evolution continues today. Humans are still evolving, with natural selection acting on traits such as resistance to diseases and the ability to digest certain foods. Furthermore, our cultural and technological advancements are now a significant driver of our evolution.

The journey of human evolution is a testament to the resilience and adaptability of our species. It is a complex process that has shaped our physical traits, behaviors, and cultures. As we continue to evolve and adapt to our changing world, we carry with us the legacy of millions of years of evolution. Understanding our evolutionary history not only helps us appreciate our place in the natural world but also sheds light on our future as a species.

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Human evolution conclusion.

There is no scientifically accepted research that shows that humans have stopped evolving. Evolution is certainly still occurring and will continue to occur in humans. Humans exhibit differences in reproductive success, which directly leads to evolution. Humans still face challenges to survival as well, and exhibit variation in heritable traits, all characteristics of evolution. Some of the confusion on this topic likely arises because modern humans have not existed for an extensive period of time, evolutionarily speaking. Many of humanities most esteemed innovations have happened in the past decade or century, merely a few generations at most. However, no innovation will change the fact that humans exhibit varying reproductive success and challenges to survival, the components of evolution.

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Essay on Human Evolution: Top 6 Essays | Biology

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Here is a compilation of essays on ‘Human Evolution’ for class 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Human Evolution’ especially written for school and college students.

Essay on Human Evolution

Essay Contents:

• Essay on the Models of Human Evolution

Essay # 1.   Introduction to Human Evolution:

Evolution as a process is composed of two parts:

1. An organism reproducing mechanism that provides variable organisms. Changes to the organism are largely random and effect future generations. They are made without regard to consequences to the organism.

2. A changing environment which screens organism changes. The environment provides stress on the variable organisms that selectively allows, through competition, certain changes to become dominant and certain others to be eliminated, without consideration for the future of the mechanism.

That same process provides mechanism (organism) disintegration if a strong screening environment is not present. Evolution is a two-way process which does not always work to the long term advantage of the organism and in fact often becomes quite deadly to a given species and thereby eradicates it.

The evolutionary process is bidirectional in its effect. It may, depending on the environment, either improve a given characteristic or decay it. Since the first step in the process is largely random and most organisms are quite complex, almost all of the variations are harmful.

A characteristic of a species advances if the environment is harsh, since most harmful variations to that characteristic will be eliminated through death and suffering at a rapid rate, leaving only the inconsequential and helpful changes in the lineage.

If the environment is benign with respect to the capability of the species then the harmful changes are not eliminated and the species will degenerate to a point of balance with the environment.

Human evolution is the part of biological evolution concerning the emergence of Homo sapiens as a distinct species from other hominans, great apes and placental mammals. It is the subject of a broad scientific inquiry that seeks to understand and describe how this change occurred.

Mammals developed from primitive mammal-like reptiles during the Triassic Period, some 200-245 million years ago. After the terminal Cretaceous extinction (65 million years ago) eliminated the dinosaurs, mammals as one of the surviving groups, underwent an adaptive radiation during the Tertiary Period.

The major orders of mammals developed at this time, including the Primates to which humans belong. Other primates include the tarsiers, lemurs, gibbons, monkeys, and apes. Although we have significant differences from other primates, we share an evolutionary history that includes traits such as opposable thumbs, stereoscopic vision, larger brains, and nails replacing claws.

Primates are relatively unspecialized mammals- they have no wings, still have all four limbs, cannot run very fast, have generally weak teeth, and lack armor or thick protective hides. However, the combination of primate adaptations that include larger brains, tool use, social structure, stereoscopic color vision, highly developed forelimbs and hands, versatile teeth, and upright posture, place them among the most advanced mammals.

Approximately 20 million years ago central and east Africa was densely forested. Climatic changes resulting from plate tectonic movements and episodes of global cooling about 15 million years ago caused a replacement of the forest by a drier-adapted savanna mixed with open areas of forest. During the course of hominid evolution, periodic climate changes would trigger bursts of evolution and/or extinction.

Primates have modifications to their ulna and radius (bones of the lower arm) allowing them to turn their hand without turning their elbow. Many primates can also swivel or turn their arms at the shoulder. These two adaptations offer advantages to life in the trees.

Primates have five digits on their forelimbs. They are able to grasp objects with their forelimbs in what is known as a prehensile movement. A second modification makes one of the digits opposable, allowing the tips of the fingers and thumb to touch.

Placement of the eyes on the front of the head increases depth perception, an advantageous trait in tree-dwelling primates. Changes in the location of rods and cones in the eye adapted primates for color vision as well as peripheral vision in dim light.

Upright posture allows a primate to view its surroundings as well as to use its hands for some other task. Hominids, the lineage leading to humans, had changes in the shape and size of their pelvis, femur, and knees that allowed bipedalism (walking on two legs). The change from quadruped to biped happened in stages, culminating in humans, who can walk or run on two legs.

Several trends of primate evolution are evident in the teeth and jaw. First, change in the geometry of the jaw reduced the snout into a flat face. Second, changes in tooth arrangement and numbers increased the efficiency of those teeth for grinding food. Third, about 1.5 million years ago our diet changed from fruits and vegetables to include meat.

Essay # 2. Origin of Apes and Hominids:

The fossil record indicates primates evolved about approximately 30 million years ago in Africa. One branch of primates evolved into the Old and New World Monkeys, the other into the hominoids (the line of descent common to both apes and man).

Fossil hominoids occur in Africa during the Miocene epoch of the Tertiary period. They gave rise to an array of species in response to major climate fluxes in their habitats. However, the nature of those habitats leads to an obscuration of the line that leads to humans (the hominids).

Until a few years ago, the ramapiths were thought to have given rise to the hominids. We now consider ramapiths ancestral to the orangutang. The hominid line arose from some as-yet-unknown ancestor. Lacking fossil evidence, biochemical and DNA evidence suggests a split of the hominid from hominoid line about 6 to 8 million years ago.

Australopithecus afarensis, the first of the human-like hominids we know of, first appeared about 3.6-4 million years ago. This species had a combination of human (bipedalism) and apelike features (short legs and relatively long arms). The arm bones were curved like chimps, but the elbows were more human-like. Scientists speculate that A. afarensis spent some time climbing trees, as well as on the ground.

Australopithecus ramidus is an older species, about 4.4 million years, and is generally considered more anatomically primitive than A. afarensis. The relationship between the two species remains to be solved.

History of Man:

I. Ardipithicus ramidus- 5 to 4 million years ago

II. Australopithecus anamensis- 4.2 to 3.9 million years ago

III. Australopithecus afarensis- 4 to 2.7 million years ago

IV. Australopithecus africanus- 3 to 2 million years ago

V. Australopithecus robustus- 2.2 to 1.6 million years ago

VI. Homo habilis- 2.2 to 1.6 million years ago

VII. Homo erectus- 2.0 to 0.4 million years ago

VIII. Homo sapiens archaic- 400 to 200 thousand years ago

IX. Homo sapiens neandertalensis- 200 to 30 thousand years ago

X. Homo sapiens sapiens- 200 thousand years ago to present.

The role of A. afarensis as the stem from which the other hominids arose is in some dispute. About 2 million years ago, after a long million year period of little change, as many as six hominid species evolved in response to climate changes associated with the beginning of the Ice Age.

Two groups developed- the australopithecines, generally smaller brained and not users of tools; and the line that led to genus Homo, larger brained and makers and users of tools. The australopithecines died out 1 million years ago; Homo, despite their best efforts (atomic weapons, pollution) is still here!

With an incomplete fossil record, australopithecines, at least the smaller form, A. africanus, was thought ancestral to Homo. Recent discoveries however have caused a reevaluation of that hypothesis. One pattern is sure, human traits evolved at different rates and at different times, in a mosaic- some features (skeletal, dietary) establishing themselves quickly, others developing later (tool making, language, use of fire).

A cluster of species developed about 2-2.5 million years ago in Africa. Homo had a larger brain and a differently shaped skull and teeth than the australopithecines. About 1.8 million years ago, early Homo gave rise to Homo erectus, the species thought to have been ancestral to our own.

Soon after its origin (1.8 million but probably older than 2 million years ago) in Africa, Homo erectus appears to have migrated out of Africa and into Europe and Asia. Homo erectus differed from early species of Homo in having a larger brain size, flatter face, and prominent brow ridges. Homo erectus is similar to modern humans in size, but has some differences in the shape of the skull, a receding chin, brow ridges, and differences in teeth.

Homo erectus was the first hominid to:

1. Provide evidence the social and cultural aspects of human evolution.

2. Leave Africa (living in Africa, Europe, and Asia).

3. Use fire.

4. Have social structures for food gathering.

5. Utilize permanent settlements.

6. Provide a prolonged period of growth and maturation after birth Between 100,000 and 500,000 years ago, the world population of an estimated 1 million Homo erectus disappeared, replaced by a new species, Homo sapiens. How, when and where this new species arose and how it replaced its predecessor remain in doubt. Answering those questions has become a multidisciplinary task.

Two hypotheses differ on how and where Homo sapiens originated:

1. The Out-of-Africa Hypothesis proposes that some H. erectus remained in Africa and continued to evolve into H. sapiens, and left Africa about 100,000-200,000 years ago. From a single source, H. sapiens replaced all populations of H. erectus.

Human populations today are thus all descended from a single speciation event in Africa and should display a high degree of genetic similarity. Support for this hypothesis comes from DNA studies of mitochondria- since African populations display the greatest diversity of mitochondrial DNA, modern humans have been in Africa longer than they have been elsewhere. Calculations suggest all modern humans are descended from a population of African H. sapiens numbering as few as 10,000.

2. The Regional Continuity Hypothesis suggests that regional populations of H. erectus evolved into H. sapiens through interbreeding between the various populations. Evidence from the fossil record and genetic studies supports this idea.

Scientists can often use the same “evidence” to support contrasting hypotheses depending on which evidence (fossils or molecular clock/ DNA studies) one gives more weight to. The accuracy of the molecular clock, so key to the out-of-Africa hypothesis, has recently been questioned.

Recent studies on the Y-chromosome seem to weaken the regional continuity hypothesis by indicating a single point-of-origin for our species some 270,000 years ago. Continued study will no doubt reveal new evidence and undoubtedly new hypotheses will arise. It is a task for all of us to weigh the evidence critically and reach a supportable conclusion, whether we are scientists or not.

Essay # 3. H istory of the Primates:

Before Homo:

The evolutionary history of the primates can be traced back for some 85 million years, as one of the oldest of all surviving placental mammal groups. Most paleontologists consider that primates share a common ancestor with the bats, another extremely ancient lineage, and that this ancestor probably lived during the late Cretaceous, together with the last dinosaurs. The oldest known primates come from North America, but they were widespread in Eurasia and Africa as well, during the tropical conditions of the Paleocene and Eocene.

With the beginning of modern climates, marked by the formation of the first Antarctic ice in the early Oligocene around 40 million years ago, primates went extinct everywhere but Africa and southern Asia. One such primate from this time was Notharctus.

Fossil evidence found in Germany 20 years ago was determined to be about 16.5 million years old, some 1.5 million years older than similar species from East Africa. It suggests that the primate lineage of the great apes first appeared in Eurasia and not Africa.

The discoveries suggest that the early ancestors of the hominids (the family of great apes and humans) migrated to Eurasia from Africa about 17 million years ago, just before these two continents were cut off from each other by an expansion of the Mediterranean Sea. These primates flourished in Eurasia and that their lineage leading to the African apes and humans —Dryopithecus—migrated south from Europe or Western Asia into Africa.

The surviving tropical population, which is seen most completely in the upper Eocene and lowermost Oligocene fossil beds of the Fayum depression southwest of Cairo, gave rise to all living primates—lemurs of Madagascar, lorises of Southeast Asia, galagos or “bush babies” of Africa, and the anthropoids; platyrrhines or New World monkeys, and catarrhines or Old World monkeys and the great apes and humans.

The earliest known catarrhine is Kamoyapithecus from uppermost Oligocene at Eragaleit in the northern Kenya rift valley, dated to 24 mya (millions of years before present). Its ancestry is generally thought to be close to such genera as Aegyptopithecus, Propliopithecus, and Parapithecus from the Fayum, at around 35 mya.

There are no fossils from the intervening 11 million years. No near ancestor to South American platyrrhines, whose fossil record begins at around 30 mya, can be identified among the North African fossil species, and possibly lies in other forms that lived in West Africa that were caught up in the still-mysterious transatlantic sweepstakes that sent primates, rodents, boa constrictors, and cichlid fishes from Africa to South America sometime in the Oligocene.

In the early Miocene, after 22 mya, many kinds of arboreally adapted primitive catarrhines from East Africa suggest a long history of prior diversification. Because the fossils at 20 mya include fragments attributed to Victoriapithecus, the earliest cercopithecoid, the other forms are (by default) grouped as hominoids, without clear evidence as to which are closest to living apes and humans.

Among the presently recognised genera in this group, which ranges up to 13 mya, we find Proconsul, Rangwapithecus, Dendropithecus, Limnopithecus, Nacholapithecus, Equatorius, Nyanzapithecus, Afropithecus, Heliopithecus, and Kenyapithecus, all from East Africa.

The presence of other generalised non-cercopithecids of middle Miocene age from sites far distant—Otavipithecus from cave deposits in Namibia, and Pierolapithecus and Dryopithecus from France, Spain and Austria—is evidence of a wide diversity of forms across Africa and the Mediterranean basin during the relatively warm and equable climatic regimes of the early and middle Miocene.

The youngest of the Miocene hominoids, Oreopithecus, is from 9 mya coal beds in Italy.

Molecular evidence indicates that the lineage of gibbons (family Hylobatidae) became distinct between 18 and 12 Ma, and that of orangutans (subfamily Ponginae) at about 12 Ma; we have no fossils that clearly document the ancestry of gibbons, which may have originated in a so far unknown South East Asian hominid population, but fossil proto-orangutans may be represented by Ramapithecus from India and Griphopithecus from Turkey, dated to around 10 Ma.

It has been suggested that species close to last common ancestors of gorillas, chimpanzees and humans may be represented by Nakalipithecus fossils found in Kenya and Ouranopithecus found in Greece.

Molecular evidence suggests that between 8 and 4 mya, first the gorillas, and then the chimpanzee (genus Pan) split off from the line leading to the humans; human DNA is 98.4 percent identical to the DNA of chimpanzees. We have no fossil record, however, of either group of African great apes, possibly because bones do not fossilize in rain forest environments.

Hominines, however, seem to have been one of the mammal groups (as well as antelopes, hyenas, dogs, pigs, elephants, and horses) that adapted to the open grasslands as soon as this biome appeared, due to increasingly seasonal climates, about 8 mya, and their fossils are relatively well known.

The earliest are Sahelanthropus tchadensis (7- 6 mya) and Orrorin tugenensis (6 mya), followed by:

1. Ardipithecus (5.5-4.4 mya), with species Ar. kadabba and Ar. Ramidus.

2. Australopithecus (4-2 mya), with species Au. anamensis, Au. afarensis, Au. africanus, Au. bahrelghazali, and Au. Garhi.

3. Kenyanthropus (3-2.7 mya), with species Kenyanthropus platyops.

4. Paranthropus (3-1.2 mya), with species P. aethiopicus, P. boisei, and P. robustus.

5. Homo (2 mya-present), with species Homo habilis, Homo rudolfensis, Homo ergaster, Homo georgicus, Homo antecessor, Homo cepranensis, Homo erectus, Homo heidelbergensis, Homo rhodesiensis, Homo sapiens neanderthalensis, Homo sapiens idaltu, Archaic Homo sapiens, Homo floresiensis.

Essay # 4. Genus of Homo:

The word homo is Latin for “human”, chosen originally by Carolus Linnaeus in his classification system. It is often translated as “man”, although this can lead to confusion, given that the English word “man” can be generic like homo, but can also specifically refer to males. Latin for “man” in the gender-specific sense is vir (pronounced weer), cognate with “virile” and “werewolf”. The word “human” is from humanus, the adjectival form of homo.

In modern taxonomy, Homo sapiens are the only extant species of its genus, Homo. Likewise, the ongoing study of the origins of Homo sapiens often demonstrates that there were other Homo species, all of which are now extinct. While some of these other species might have been ancestors of H. sapiens, many were likely our “cousins”, having speciated away from our ancestral line.

There is not yet a consensus as to which of these groups should count as separate species and which as subspecies of another species. In some cases this is due to the paucity of fossils, in other cases it is due to the slight differences used to classify species in the Homo genus. The Sahara pump theory provides an explanation of the early variation in the genus Homo.

i. Homo Habilis:

H. habilis lived from about 2.4 to 1.4 million years ago (mya). H. habilis, the first species of the genus Homo, evolved in South and East Africa in the late Pliocene or early Pleistocene, 2.5-2 mya, when it diverged from the Australopithecines.

H. habilis had smaller molars and larger brains than the Australopithecines, and made tools from stone and perhaps animal bones. One of the first known hominids, it was nicknamed ‘handy man’ by its discoverer, Louis Leakey. Some scientists have proposed moving this species out of Homo and into Australopithecus.

ii. Homo Rudolfensis and Homo Georgicus:

These are proposed species names for fossils from about 1.9 -1.6 mya, the relation of which with H. habilis is not yet clear. H. rudolfensis refers to a single, incomplete skull from Kenya. Scientists have suggested that this was just another habilis, but this has not been confirmed.

H. georgicus, from Georgia, may be an intermediate form between H. habilis and H. erectus, or a sub-species of H. erectus.

iii. Homo Ergaster and Homo Erectus:

The first fossils of Homo erectus were discovered by Dutch physician Eugene Dubois in 1891 on the Indonesian island of Java. He originally gave the material the name Pithecanthropus erectus based on its morphology that he considered to be intermediate between that of humans and apes.

H. erectus lived from about 1.8 mya to 70,000 years ago. Often the early phase, from 1.8 to 1.25 mya, is considered to be a separate species, H. ergaster, or it is seen as a subspecies of erectus, Homo erectus ergaster.

In the Early Pleistocene, 1.5-1 mya, in Africa, Asia, and Europe, presumably, Homo habilis evolved larger brains and made more elaborate stone tools; these differences and others are sufficient for anthropologists to classify them as a new species, H. erectus. In addition H. erectus was the first human ancestor to walk truly upright.

This was made possible by the evolution of locking knees and a different location of the foramen magnum (the hole in the skull where the spine enters). They may have used fire to cook their meat.

A famous example of Homo erectus is Peking Man; others were found in Asia (notably in Indonesia), Africa, and Europe. Many paleoanthropologists are now using the term Homo ergaster for the non-Asian forms of this group, and reserving H. erectus only for those fossils found in the Asian region and meeting certain skeletal and dental requirements which differ slightly from ergaster.

iv. Homo Cepranensis and Homo Antecessor:

These are proposed as species that may be intermediate between H. erectus and H. heidelbergensis.

H. cepranensis refers to a single skull cap from Italy, estimated to be about 800,000 years old.

H. antecessor is known from fossils from Spain and England that are 800,000-500,000 years old.

v. Homo Heidelbergensis:

H. heidelbergensis (Heidelberg Man) lived from about 800,000 to about 300,000 years ago. Also proposed as Homo sapiens heidelbergensis or Homo sapiens paleohungaricus.

vi. Homo Neanderthalensis:

H. neanderthalensis lived from about 250,000 to as recent as 30,000 years ago. Also proposed as Homo sapiens neanderthalensis- there is ongoing debate over whether the ‘Neanderthal Man’ was a separate species, Homo neanderthalensis, or a subspecies of H. sapiens.

While the debate remains unsettled, evidence from mitochondrial DNA and Y-chromosomal DNA sequencing indicates that little or no gene flow occurred between H. neanderthalensis and H. sapiens, and, therefore, the two were separate species.

vii. Homo Rhodesiensis, and the Gawis Cranium:

H. rhodesiensis, estimated to be 300,000-125,000 years old, most current experts believe Rhodesian Man to be within the group of Homo heidelbergensis though other designations such as Archaic Homo sapiens and Homo sapiens rhodesiensis have also been proposed.

In February 2006 a fossil, the Gawis cranium, was found which might possibly be a species intermediate between H. erectus and H. sapiens or one of many evolutionary dead ends. The skull from Gawis, Ethiopia, is believed to be 500,000-250,000 years old.

Only summary details are known, and no peer reviewed studies have been released by the finding team. Gawis man’s facial features suggest its being either an intermediate species or an example of a “Bodo man” female.

viii. Homo Sapiens:

H. sapiens (“sapiens” means wise or intelligent) has lived from about 250,000 years ago to the present. Between 400,000 years ago and the second interglacial period in the Middle Pleistocene, around 250,000 years ago, the trend in cranial expansion and the elaboration of stone tool technologies developed, providing evidence for a transition from H. erectus to H. sapiens.

The direct evidence suggests that there was a migration of H. erectus out of Africa, then a further speciation of H. sapiens from H. erectus in Africa (there is little evidence that this speciation occurred elsewhere). Then a subsequent migration within and out of Africa eventually replaced the earlier dispersed H. erectus.

This migration and origin theory is usually referred to as the single- origin theory. However, the current evidence does not preclude multiregional speciation, either. This is a hotly debated area in paleoanthropology.

Current research has established that human beings are genetically highly homogenous, that is the DNA of individuals is more alike than usual for most species, which may have resulted from their relatively recent evolution or the Toba catastrophe. Distinctive genetic characteristics have arisen, however, primarily as the result of small groups of people moving into new environmental circumstances.

These adapted traits are a very small component of the Homo sapiens genome and include such outward “racial” characteristics as skin color and nose form in addition to internal characteristics such as the ability to breathe more efficiently in high altitudes.

H. sapiens idaltu, from Ethiopia, lived from about 160,000 years ago (proposed subspecies). It is the oldest known anatomically modern human.

ix. Homo Floresiensis :

H. floresiensis, which lived about 100,000-12,000 years ago has been nicknamed hobbit for its small size, possibly a result of insular dwarfism. H. floresiensis is intriguing both for its size and its age, being a concrete example of a recent species of the genus Homo that exhibits derived traits not shared with modern humans.

In other words, H. floresiensis share a common ancestor with modern humans, but split from the modern human lineage and followed a distinct evolutionary path. The main find was a skeleton believed to be a woman of about 30 years of age. Found in 2003 it has been dated to approximately 18,000 years old. Her brain size was only 380 cm 3 (which can be considered small even for a chimpanzee). She was only 1 meter in height.

However, there is an ongoing debate over whether H. floresiensis is indeed a separate species. Some scientists presently believe that H. floresiensis was a modern H. sapiens suffering from pathological dwarfism.

Use of Tools:

Using tools has been interpreted as a sign of intelligence, and it has been theorized that tool use may have stimulated certain aspects of human evolution—most notably the continued expansion of the human brain. Paleontology has yet to explain the expansion of this organ over millions of years despite being extremely demanding in terms of energy consumption.

The brain of a modern human consumes about 20 Watts (400 kilocalories per day), which is one fifth of the energy consumption of a human body. Increased tool use would allow for hunting and consuming meat, which is more energy-rich than plants. Researchers have suggested that early hominids were thus under evolutionary pressure to increase their capacity to create and use tools.

Precisely when early humans started to use tools is difficult to determine, because the more primitive these tools are (for example, sharp-edged stones) the more difficult it is to decide whether they are natural objects or human artifacts.

Stone Tools:

Stone tools are first attested around 2.6 million years ago, when H. habilis in Eastern Africa used so-called pebble tools, choppers made out of round pebbles that had been split by simple strikes.

This marks the beginning of the Paleolithic, or Old Stone Age; its end is taken to be the end of the last Ice Age, around 10,000 years ago. The Paleolithic is subdivided into the Lower Paleolithic (Early Stone Age, ending around 350,000-300,000 years ago), the Middle Paleolithic (Middle Stone Age, until 50,000-30,000 years ago), and the Upper Paleolithic.

The period from 700,000-300,000 years ago is also known as the Acheulean, when H. ergaster (or erectus) made large stone hand-axes out of flint and quartzite, at first quite rough (Early Acheulian), later “retouched” by additional, more subtle strikes at the sides of the flakes.

After 350,000 BP (Before Present) the more refined so-called Levallois technique was developed. It consisted of a series of consecutive strikes, by which scrapers, slicers (“racloirs”), needles, and flattened needles were made. Finally, after about 50,000 BP, ever more refined and specialised flint tools were made by the Neanderthals and the immigrant Cro-Magnons (knives, blades, skimmers). In this period they also started to make tools out of bone.

Essay # 5. Evolution of Neanderthals :

Archaic H. sapiens lived from 500,000 to 30,000 years ago and combined features of H. sapiens with those of H. erectus. The Neanderthals, considered in this group, lived in Europe and western Asia between 100,000 and 30,000 years ago before their disappearance.

Neanderthals were larger-brained than modern humans, had a sloping forehead, prominent brow ridges and a receding chin. They had a very prominent nose and ranged in height from 5 foot 2 inches (average female) to 5 foot 6 inches (average male).

Despite their image as brutish simpletons, Neanderthals were the first humans to bury their dead with artifacts, indicating abstract thought, perhaps a belief in an after-life. They lived in free-standing settlements, as well as caves. Neanderthal tools were more sophisticated than H. erectus’ tools, employing handles to gain extra leverage.

Did Neanderthals evolve gradually into modern humans, or were they replaced by modern forms originating from a single population? The answer to that depends on the answer to the question of the origin of H. sapiens from H. erectus. The out-of-Africa hypothesis suggests Neanderthals were a separate species (H. neandertalensis) replaced as modern humans (H. sapiens) spread from Africa. The regional continuity hypothesis suggests Neanderthals were a subspecies (H. sapiens neandertalensis) that evolved into modern humans (H. sapiens sapiens).

Agriculture and Migrations :

Since the evolution of H. erectus, migrations have been a fact of human existence, helping to spread genetic diversity as well as technological innovation. The most recent innovations have not been physical, but rather cultural.

The Neolithic transition, about 10,000 years ago, involved the change from hunter-gatherer societies to agricultural ones based on cultivation of plants and domesticated animals. Evidence suggests this began in the Middle East and spread outward via migrations. Genetic studies suggest agriculture spread by the migration of farmers into hunter-gatherer societies. This would produce a genetic blurring as the farmers interbred with the indigenous peoples, a pattern supported by genetics.

Most anthropologists agree that the New World was populated by a series of three migrations over the temporary land connection between Asia and North America. The Immigrants spread southward, eventually reaching Tierra del Fuego in the southernmost part of South America.

Anthropological and linguistic studies find three groups of peoples:

1. The Amerinds, who spread across North and South America.

2. The Na-Denes, who occupied the northwestern region of North America.

3. The Eskaleuts, Eskimo and Aleut peoples who live in the far north.

Mitochondrial DNA studies find four distinct groups descended from peoples of Siberia. Amerind mtDNA suggests two waves of migration (one perhaps as old as 21-42 thousand years ago). The genetic model confirms the accepted ideas about human migration into the Americas and suggests a possible fourth wave.

Essay # 6. Models of Human Evolution:

Today, all humans are classified as belonging to the species Homo sapiens sapiens. However, this is not the first species of hominids- the first species of genus Homo, Homo habilis evolved in East Africa at least 2 million years ago, and members of this species populated different parts of Africa in a relatively short time.

Homo erectus evolved more than 1.8 million years ago, and by 1.5 million years ago had spread throughout the Old World. Virtually all physical anthropologists agree that Homo sapiens evolved out of Homo erectus.

Anthropologists have been divided as to whether Homo sapiens evolved as one interconnected species from H. erectus (called the Multiregional Model, or the Regional Continuity Model), or evolved only in East Africa, and then migrated out of Africa and replaced H. erectus populations throughout the Old World (called the Out of Africa Model or the Complete Replacement Model).

Anthropologists continue to debate both possibilities, and the evidence is technically ambiguous as to which model is correct, although most anthropologists currently favor the Out of Africa model.

Multiregional Model :

Advocates of the Multiregional model, primarily Milford Wolpoff and his followers, have argued that the simultaneous evolution of H. sapiens in different parts of Europe and Asia would have been possible if there was a degree of gene flow between archaic populations.

Similarities of morphological features between archaic European and Chinese populations and modern H. sapiens from the same regions, Wolpoff argues, support a regional continuity only possible within the Multiregional model. Wolpoff and others further argue that this model is consistent with clonal patterns of phenotypic variation.

Out of Africa Model :

According to the Out of Africa Model, developed by Christopher Stringer and Peter Andrews, modern H. sapiens evolved in Africa 200,000 years ago. Homo sapiens began migrating from Africa between 70,000 – 50,000 years ago and would eventually replace existing hominid species in Europe and Asia.

The Out of Africa Model has gained support by recent research using mitochondrial DNA (mtDNA). After analysing genealogy trees constructed using 133 types of mtDNA, they concluded that all were descended from a woman from Africa, dubbed Mitochondrial Eve.

A variation on this model involves the Southern dispersal theory, which has gained support in recent years from genetic, linguistic and archaeological evidence. In this theory, there was a coastal dispersal of modern humans from the Horn of Africa around 70,000 years ago. This group helped to populate Southeast Asia and Oceania, explaining the discovery of early human sites in these areas much earlier than those in the Levant.

A second wave of humans dispersed across the Sinai peninsula into Asia, resulting in the bulk of human population for Eurasia. This second group possessed a more sophisticated tool technology and was less dependent on coastal food sources than the original group. Much of the evidence for the first group’s expansion would have been destroyed by the rising sea levels at the end of the Holocene era.

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How Did Belief Evolve?

About 20 years ago, the residents of Padangtegal village in Bali, Indonesia, had a problem. The famous, monkey-filled forest surrounding the local Hindu temple complex had become stunted, and saplings failed to sprout and thrive. Since I was conducting fieldwork in the area, the head of the village council, Pak Acin, asked me and my team to investigate.

We discovered that locals and tourists visiting the temples had previously brought food wrapped in banana leaves, then tossed the used leaves on the ground. But when plastic-wrapped meals became popular, visitors threw the plastic onto the forest floor, where it choked the young trees.

I told Acin we would clean up the soil and suggested he enact a law prohibiting plastic around the temples. He laughed and told us a ban would be useless. The only thing that would change people’s behavior was belief. What we needed, he said, was a goddess of plastic.

Over the next year, our research team and Balinese collaborators didn’t exactly invent a Hindu deity. But we did harness Balinese beliefs and traditions about harmony between people and environments. We created new narratives about plastic, forests, monkeys, and temples. We developed ritualistic caretaking behaviors that forged new relationships between humans, monkeys, and forests.

As a result, the soils and undergrowth were rejuvenated, the trees grew stronger and taller, and the monkeys thrived. Most importantly, the local community reaped the economic and social benefits of a healthy, vigorous forest and temple complex.

Acin taught me that science and rules cannot ensure lasting change without belief—the most creative and destructive ability humans have ever evolved.

Most people assume “belief” refers to religion. But it is so much more. Belief is the ability to combine histories and experiences with imagination, to think beyond the here and now. It enables humans to see, feel, and know  an idea that is not immediately present to the senses, then wholly invest in making that idea one’s reality.

We must believe in ideas and abilities in order to invent iPhones, construct rockets, and make movies. We must believe in the value of goods, currencies, and knowledge to build economies. We must believe in collective ideals, constitutions, and institutions to form nations. We must believe in love (something no one can clearly see, define, or understand) to engage in relationships.

In my recent book, Why We Believe , I explore how we evolved this universally and uniquely human capacity, drawing on my 26 years of research into human and other primates’ evolution, biology, and daily lives. [1] [1] Portions of this essay come from the author’s book Why We Believe  (Yale University Press, 2019). Our 2-million-year journey to complex religions, political philosophies, and technologies essentially follows a three-step path: from imagination to meaning-making to belief systems. To trace that path, we must go back to where it started: rocks.

A little over 2 million years ago , our genus ( Homo ) emerged and pushed the evolutionary envelope. Its hominin ancestors had been doing pretty well as socially dynamic, cognitively complex, stone tool–wielding primates. But Homo ratcheted up reliance on one another to better evade predators, forage and process new foods, communally raise young, and fashion superior stone tools.

One of the skills that helped Homo succeed was imagination—an ability you can use now to picture how it developed.

Imagine an early Homo preparing the evening meal. She knows stones can be hit and flaked to form sharper utensils that cut and chop. She also knows the stone tools her ancestors made don’t do a particularly great job: They take a long time to hack the raw meat off a carcass, to smash and grind the roots the community has dug up, and to crack open bones and scoop out the delicious marrow.

One day she looks at her brethren laboring to create simple, one-sided, flaked stone tools. She sees, in her mind’s eye, flakes being removed from both sides, further sharpening the edges and balancing the shape. She creates a mental representation of a possibility—and she makes it her reality.

She and her descendants experiment with more extensive reshaping of stones—creating, for example, Acheulean hand axes. They begin to predict flaking patterns. They conceive of more diverse instruments for slicing roots and raw meat , and carving bone and wood. They translate private musings and imaginings into communal realities. When they make a discovery, they teach one another, speeding up the invention process and expanding the possibilities of their efforts.

By 500,000 years ago, Homo had mastered the skill of shaping stone, bone, hides, horns, and wood into dozens of tool types. Some of these tools were so symmetrical and aesthetically pleasing that some scientists speculate toolmaking took on a ritual aspect that connected Homo artisans with their traditions and community. These ritualistic behaviors may have evolved, hundreds of thousands of years later, into the rituals we see in religions.

With their new gadgets, Homo chopped wood, dug deeper for tubers, collected new fruits and leaves, and put a wider variety of animals on the menu. These activities—expanding their diets, constructing new ecologies, and altering the implements in their environment—literally reshaped their bodies and minds.

In response to these diverse experiences, Homo grew increasingly dynamic neural pathways that allowed them to become even more responsive to their environment. During this time period, Homo ’s brains reached their modern size .

But their brains didn’t uniformly enlarge. Parts of the frontal lobes—which play critical roles in emotional, social, motivational, and perceptual processes, as well as decision-making, attention, and working memory—expanded and elaborated at an increased rate .

Another brain organ that ballooned was the cerebellum. Over the course of hominin history, our lineage added approximately 16 billion more cerebellar neurons than would be expected for our brain size. This ancient brain organ is involved with social sensory-motor skills, imitation, and complex sequences of behavior.

These structural changes helped Homo generate more effective and expansive mental representations. What emerged was a distinctively human imagination—the capacity that allows us to create and shape our futures. It also gave rise to the next step in the evolution of belief: meaning-making.

The rise of imagination sparked positive feedback loops between creativity, social collaboration, teaching, learning, and experimenting. The advent of cooking opened up a new landscape of foods and nutrient profiles. By boiling, barbecuing, grinding, or mashing meat and plants, Homo maximized access to proteins, fats, and minerals.

This gave them the nutrition and energy necessary for extended childhood brain development and increased neural connectivity. It allowed them to travel greater distances. It enabled them to evolve neurobiologies and social capacities that made it possible to move from imagining and making new tools to imagining and making new ways of being human.

By about 200,000 years ago, Homo had begun to push the artistic envelope. Groups of Homo sapiens were coloring their stone tools with ochres—red, yellow, and brown pigments made of iron oxide. They were likely also using ochres to paint their bodies and cave walls.

Ochre decoration requires far more complicated cognitive processes than, for example, an Australasian bowerbird arranging sparkling glass and other baubles around its nest to attract a mate. It requires the kind of complex creative sequences made possible by elaborate frontal lobes, a dense cerebellum, and more diverse and intricate social relationships.

Imagine an early Homo sapiens who wants to paint a stone ax. She and her companions must seek out specific types of rocks and use a tool to scrape off the iron oxides. Then, they might manipulate the minerals’ chemistry, mixing them with water to transform them into pigments or heating them to turn them from yellow to red. Finally, they must apply the paint to the ax, changing how light reflects off its surface—making it look different, making it into a new thing.

When early humans colored something (or someone) red or yellow, it changed the way they perceived that tool, that cave, that person. They were using their imagination to reshape their world to match their desired perceptions of it. They were imbuing objects and bodies with a new, shared meaning.

Gradually, they established relations with more and more distant groups, sharing meanings for the items they swapped and the interactions they exchanged. In short, Homo sapiens began engaging full time in meaning-making.

Collective meaning-making changes the way humans perceive and experience the world. It enables us to do the wildly imaginative, creative, and destructive things we do. It is during this period that Homo broke the boundaries of the material and the visible so the realm of pure imagination could be made tangible.

When a typhoon smashes into land, it tosses trees like matchsticks and fills the air with a deafening roar that drowns out voices. For millennia, every animal caught in such a storm feared it, hunkered down, and waited for it to pass. But at some point, members of the genus Homo began to explain it.

We don’t know when it happened, but within the last few hundred thousand years, humans had developed the imagination, the thirst for meaning, and the communication skills necessary for creating explanations of mysterious phenomena.

By 300,000 to 400,000 years ago, human groups across the planet were sparking fires with sticks and stones, and carefully transporting the flames. And by 80,000 years ago, they were carrying water in intricately carved ostrich eggshells . They made glues to craft containers, adorned themselves with beads, painted with multi-ingredient pigments, and etched geometric patterns into shells, stones, and bones.

These kinds of hyper-complex, multi-sequence behaviors cannot simply be imitated. They require explanation. So, when researchers see multiple instances of abstract art and creative crafts, we assume individuals were engaging in deep, intricate communication based on shared meanings.

By at least 40,000 to 50,000 years ago, representational art arose : depictions of hunts, animal-human hybrids, blazing sunsets, and hand prints waving, as if they are signaling meaning across the deep gap of time.

Once groups are attributing shared meaning to objects they can manipulate, it is an easy jump to give shared meaning to larger elements they cannot change: storms, floods, earthquakes, volcanoes, eclipses, and even death. We have evidence that by at least a few hundred thousand years ago, early humans were placing their dead in caves . Within the past 50,000 years, distinct examples of burial practices became more and more common.

Through language, deeply held thoughts and imaginings could be transferred rapidly and effectively from individuals to small groups to wider populations. This created large-scale shared structures of meaning—what we call belief systems.

Between about 4,000 to 15,000 years ago, numerous radical transitions occurred in many populations. Humans started to domesticate plants and animals. They developed, along with agriculture, substantial food storage capacities and technologies. Concepts of property and inequality emerged. Towns and, eventually, cities grew. All of this led to the formation of multi-community settlements with stratified political and economic structures.

This restructuring profoundly shaped, and was shaped by, belief systems. Toward the end of this period—by 4,000 to 8,000 years ago—we see clear evidence of formal religious institutions: monuments, gathering places, sanctuaries, and altars.

There are numerous explanations for the evolution of religions, and none of them by itself is satisfactory. Some proposals are psychological: Our ancestors understood that other individuals have different mental states, motivation, and agency, so they attributed those same qualities to supernatural agents to explain everything from lightning to illness.

Other researchers note that the rise of huge, hierarchical communities that engaged in large-scale cooperation and warfare correlated with the rise of far-reaching, hierarchical religions with powerful, moralizing deities. Some scientists posit that “big groups” prompted the creation of “big gods” who could enforce order and cooperation in unruly societies. Other researchers hypothesize the reverse: that humans first created “big god” religions in order to coordinate larger and larger social groups.

Still other experts say the human capacity for imagination became so expansive it reached beyond the real and the possible into the unreal and the impossible. This generated the capacity for transcendence—a central feature in the religious experience.

But though belief can be transcendent, creative, and unifying, not all of humanity’s beliefs are beneficial.

For example, many humans today believe the world should be exploited for our benefit. Many believe that racial, gendered, and xenophobic inequalities are a “natural” result of inherent differences. Many believe in religious, scientific, or political fundamentalism, which is often used as a weapon against other belief systems.

Over the past 2 million years, we have evolved a capacity that has benefited humans but can also introduce horrible possibilities. It is up to us to manage how we use this power.

Now that we have asked, Why do we believe? , we should ask, What do we want to believe, for the sake of humanity?

This article was republished on discovermagazine.com .

Agustín Fuentes is a professor of anthropology at Princeton University. He focuses on the biosocial, delving into the entanglement of biological systems with the social and cultural lives of humans, our ancestors, and a few other animals with whom humanity shares close relations. Earning his B.A./B.S. in anthropology and zoology and his M.A. and Ph.D. in anthropology from the University of California, Berkeley, he has conducted research across four continents, multiple species, and 2 million years of human history. His current projects include exploring cooperation, creativity, and belief in human evolution, multispecies anthropologies, evolutionary theory and processes, sex/gender, and engaging race and racism. Fuentes’ books include Race, Monogamy, and Other Lies They Told You: Busting Myths About Human Nature , The Creative Spark: How Imagination Made Humans Exceptional , and Why We Believe: Evolution and the Human Way of Being . 

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Essay on the Origin of Human Knowledge, translated and edited by Hans Aarsleff

Etienne Bonnot de Condillac, Essay on the Origin of Human Knowledge, translated and edited by Hans Aarsleff , Cambridge Texts in the History of Philosophy, Cambridge University Press, 2001, 274 pp, $22.00 (pbk), ISBN 0-521-58576-7.

Reviewed by Jonathan Israel, unkown

The publication of this expertly edited and translated version of the Essai sur l’origine des connaissances humaines (1746) of the Abbé Etienne Bonnot de Condillac (1715-80) is welcome from several points of view and perhaps especially because French and other continental philosophy of the Enlightenment is still insufficiently known and discussed in the English-speaking world. During the late 1740s and early 1750s, Condillac undeniably made a substantial philosophical contribution and has even been described as “certainly the most important French eighteenth century thinker in the field of epistemology (or ‘metaphysics’ as his contemporaries tended to call it)”. 1 At the same time, there is a long tradition of stressing Condillac’s debt to Locke, or referring to “Condillac’s brand of Lockean thought”. 2 According to Hans Aarsleff, Condillac “admired Locke as the best of philosophers because he had studied the operations of the mind without reliance on postulates about its essential nature (p. xv). According to Condillac’s original translator into English, Thomas Nugent, Condillac “followed the footsteps of the celebrated Mr. Locke, not amusing his reader with airy speculations about the nature of the human mind, but attempting to make an exact analysis of its power and capacity, to know its operations, to ascend to the origin and formation of our ideas, in order to settle the boundaries of human knowledge”. 3

Indeed, Condillac has often seemed a useful exemplum for those who consider Locke and Newton the prime patron saints of the Enlightenment and who hold that philosophically, unlike in their social and political thought, the philosophes essentially just followed the British lead. Yet it is not at all clear that scholars have been justified in drawing this inference. Indeed, when examined closely, it would seem that Condillac’s argument is not really Lockean at all, indeed that his gentle critique of Locke, in the Essay , is in reality scarcely less devastating than his onslaught on Descartes, Malebranche and the Leibnizio-Wolffian school.

Undoubtedly, Condillac, like so many of the philosophes of the High Enlightenment was deeply preoccupied with working out the implications of the great philosophical systems of the late seventeenth century. It is also true that Condillac is markedly more positive and polite when discussing Locke than when touching on Descartes, Malebranche or Wolff. But it has it be remembered that throughout continental Europe from the 1720s onwards, it was a widely familiar philosophical tactic to present one’s arguments under the auspices of Locke since Locke was the one major recent philosopher who was broadly acceptable to both the Catholic authorities –even in Spain – and Protestant theologians, being regarded as a safe pair of hands, the thinker who reconciles philosophy and theology and most satisfactorily protected miracles and the sphere of the supernatural. Claiming allegiance to Locke then was a way of claiming respectability and distancing oneself from more controversial and suspect systems.

In contrast to more obviously radical thinkers, such as La Mettrie or Diderot, Condillac—who entered the Catholic priesthood in 1741 but is said to have only celebrated mass once in his life—not infrequently invokes divine providence and the supernatural and was clearly anxious to placate conservative opinion; and, for this reason, it made eminently good sense for him to convey an air of proximity to English empiricism and remain silent about Spinoza’s epistemology. Yet when examined carefully, many of his comments on Locke are actually quite far-reaching criticisms, and as one reads on, it emerges that Condillac for all intents and purposes is demolishing Locke’s system and replacing it with something that is no longer in any meaningful sense Lockean. Thus, for Locke, sense is one thing, mind another; and while he avoids the dogmatic dualism characteristic of Cartesianism, there can be no doubt that it remains a high priority in Locke’s system that ample room be reserved for the separate existence (and presumed immortality) of the mind/soul. In effect he comes close to advocating a mind-body substance dualism without formally attempting to substantiate it. That is why Locke postulates a mind that is like a tabula rasa , something on which sense perceptions leave imprints and insists that thinking and willing are mental and not bodily functions. According to Locke, man is a body but also, at least as a working hypothesis ‘an immaterial thinking being’.

In Condillac’s eyes, Locke improved significantly on the Cartesians by seeing the origin of knowledge in the senses. But he signally failed “to examine the early progress of the operations of the mind” (p. 214). Condillac makes at least two and possibly three crucial moves which he claims Locke neglected to make, or should have made had he been rigorously consistent with his own principles. Firstly, by focusing on ‘first operations of mind’ and reducing these to the desire to experience more strongly, or ‘attend to’, certain specially striking, pleasurable, or painful, sensations, he argues that the human mind operates by connecting and recalling sensations. From this he proceeds to reduce all human thought to the ordering and elaboration of sensations: “the perception or the impression occasioned in the mind by the action of the senses is the first operation of the understanding” (p. 19). Everything else follows from that.

Secondly, Condillac lays great stress on our ability to mark, memorize, and discuss ideas by employing ‘signs’ – that is numbers, symbols or words – to represent them. Whereas for Locke, as Descartes, reasoned thought in the mind remains autonomous from expression in language, in Condillac language becomes the instrument of the higher forms of perception, enabling them to be transformed into ideas. Furthermore, what man expresses in the initial stages of language, before he matures to the level of being able to employ language as a vehicle for abstract ideas, is overwhelmingly declamation of raw emotion and appetite, after which he graduates to an intermediate stage where the aesthetic dimension, his responses to sentiment, rhythm and beauty, dominate his increasingly elaborate use of language. Hence the arts precede and are more basic than reason while language and linguistic usage, according to Condillac, pass through an evolution which mirrors the evolution of human reason itself.

Condillac, then, replaces Locke’s conception of mind as something non-physical and yet inherent in man which receives impressions from the senses and then reflects on them—that is what Cassirer called the ‘prejudice regarding innate operations of the mind’—with the notion that thought is just a higher form of sense perception, a rung on the same ladder of mental operations, which, of course, brings him much closer to Spinoza’s empiricism than Locke’s. As a consequence, as various commentators have remarked – though this is given less emphasis in Aarsleff’s introduction than it might seem to deserve – Condillac steers much further than Locke ever did towards a purely materialist conception of man and a sensationalist conception of the human mind, that is towards the oneness of body and mind and therefore to something which contemporaries would deem dangerously reminiscent of Spinozism. This uncompromising reductionism of thought to perception, as various commentators have pointed out, notably contributed to the purely materialist view of man evolving in the minds of Condillac’s more radical contemporaries such as Diderot and Helvétius.

But Condillac was no La Mettrie or Diderot, and his rhetoric about Locke is there for a good reason. In order to counterbalance the potentially radical implications of his monist epistemology, Condillac is careful to add when stipulating “that we do not have any ideas that do not come from the senses” that this applies only to the state we are in “now after the Fall” (p. 14). In this way he deftly deploys theology to guard his philosophical flanks. Such a position as he develops in this treatise would be altogether false, he insists, if one tried to apply it “to the soul in the state of innocence or after its separation from the body” (p. 14).

1. See Peter Jimack, “The French Enlightenment II: deism, morality and politics” in Stuart Brown (ed.) Routledge History of Philosophy V: British Philosophy in the Age of Enlightenment (London and New York, 1996), p. 238

2. Robert G.Weyant, “Introduction” to Condillac, An Essay on the origin of Human Knowledge facsimile reproduction of the translation of Thomas Nugent (1756) (Gainesville, Florida, 1971), p. xiv

3. Ibid., “The translator’s preface”, p. vii

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Guest Essay

The Ancient Roots of Trump’s Attacks on Harris

By Honor Cargill-Martin

Ms. Cargill-Martin is a writer and a classical scholar.

The meddler, the schemer, the veiled power behind the throne, the poisoner, the witch. The image of sinister female power hiding in the dark permeates our cultural consciousness. It is a trope that stretches back to the ancient world, when women were excluded from politics and men sought ways to prove that their participation would be unnatural and dangerous. As ancient texts became part of the Western canon, such suspicion became ingrained into our patterns of thought, surviving long after the conditions that created them.

About an hour after Joe Biden’s withdrawal from the presidential race in July, a Trump-aligned super PAC released an attack ad . “Kamala was in on it,” a narrator says. She “knew Joe couldn’t do the job, so she did it.” Mr. Trump picked up the theme soon after. Ms. Harris had, he argued, long concealed Mr. Biden’s incapacity, to ensure her own nomination. As focus on the handover itself fades, this idea has come to underpin one of the Trump campaign’s key lines of attack: Ms. Harris has been the power behind the throne all along, and Mr. Biden simply a front. In an early August interview , JD Vance argued that Ms. Harris must have “been the one calling the shots” all along. Mr. Trump has insisted that “Day 1 for Kamala was three and a half years ago.”

The accusation that Ms. Harris covered up the state of Mr. Biden’s health is not dependent on her gender. It’s doubtless that Mr. Trump would have deployed the same argument, in one form or another, against a male opponent. But leveled against Ms. Harris, it hits upon the ancient seam of rhetoric that associates women with the clandestine exercise of power, giving it a degree of consequence it would never have carried against a man.

The Romans loved a conspiracy theory, and rumors of women-led cover-ups pepper their history. This motif took hold most robustly in the peculiar conditions of the early Roman Empire, as the male aristocrats who’d once ruled the Roman Republic became concerned that women were co-opting power that was rightfully male. It was said that after Augustus, Rome’s first emperor, died, his wife, Livia, continued to issue positive news about his health until she had secured the succession of her son Tiberius. A century later, people whispered that Pompeia Plotina, wife of the emperor Trajan, had concealed her husband’s death for some days, signing his letters to the Senate and forcing through the adoption of her favorite, Hadrian, as his successor.

When they talk about women in politics, Roman historians paint us a world of plots designed to circumvent the will of the emperor and the Roman people — and the Trump campaign suggests something similar in its vision of Ms. Harris’s “undemocratic” nomination. It is hard to find a woman of the imperial family who is not accused of using poison — the most covert means of assassination — in pursuit of her goals, and women’s intrigues were often set under cover of night. Messalina, for example, supposedly used a series of fake nightmares to dupe her husband , Claudius, into executing one of her enemies.

The rhetoric had elements of truth: The public sphere was all but exclusively accessible to men, and the strongest weapon available to women was influence exerted privately on male rulers. But it was exaggerated beyond all historical reality. The women of the imperial family were well-educated veterans of the political game, with huge public profiles. Petitioners frequently addressed missives to empresses, and some women were granted semiofficial titles that, like the vice presidency, carried the potential for (but no guarantee of) great power. Secrecy was stressed not because it reflected the truth, but because it made a point: Female power was destabilizing and the women who held it were not to be trusted.

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