End Show Slide 1 of 53 Copyright Pearson Prentice Hall Biology

End Show Slide 2 of 53 Copyright Pearson Prentice Hall 32-3 Primates and Human Origins

End Show 32-3 Primates and Human Origins Slide 3 of 53 Copyright Pearson Prentice Hall What Is a Primate? What characteristics do all primates share?

End Show 32-3 Primates and Human Origins Slide 4 of 53 Copyright Pearson Prentice Hall What Is a Primate? In general, primates have binocular vision, a well-developed cerebrum, relatively long fingers and toes, and arms that can rotate around their shoulder joints.

End Show 32-3 Primates and Human Origins Slide 5 of 53 Copyright Pearson Prentice Hall What Is a Primate? Fingers, Toes, and Shoulders Flexible digits enable primates to run along tree limbs and swing from branch to branch with ease.

End Show 32-3 Primates and Human Origins Slide 6 of 53 Copyright Pearson Prentice Hall What Is a Primate? Primates’ arms are well adapted to climbing because they can rotate in broad circles around a strong shoulder joint. In most primates, the thumb and big toe can move against the other digits. This characteristic allows primates to hold objects in their hands or feet.

End Show 32-3 Primates and Human Origins Slide 7 of 53 Copyright Pearson Prentice Hall What Is a Primate? Well-Developed Cerebrum The large cerebrum of primates enables them to display more complex behaviors than many other mammals. Many species have social behaviors that include adoption of orphans and even warfare between rival primate troops.

End Show 32-3 Primates and Human Origins Slide 8 of 53 Copyright Pearson Prentice Hall What Is a Primate? Binocular Vision Many primates have a flat face, so both eyes face forward with overlapping fields of view. This facial structure allows for binocular vision. Binocular vision is the ability to merge visual images from both eyes, providing depth perception and a three-dimensional view of the world.

End Show 32-3 Primates and Human Origins Slide 9 of 53 Copyright Pearson Prentice Hall Evolution of Primates What are the major evolutionary groups of primates?

End Show 32-3 Primates and Human Origins Slide 10 of 53 Copyright Pearson Prentice Hall Evolution of Primates The two main groups of primates are prosimians and anthropoids.

End Show 32-3 Primates and Human Origins Slide 11 of 53 Copyright Pearson Prentice Hall Evolution of Primates Tarsiers Old World monkeys Primate ancestor Hominoids Lorises and bush babies Lemurs New World monkeys Gibbons Orangutans Gorillas Chimpanzees Humans Anthropoids Prosimians

End Show 32-3 Primates and Human Origins Slide 12 of 53 Copyright Pearson Prentice Hall Evolution of Primates Prosimians Most prosimians alive today are small, nocturnal primates with large eyes that are adapted to seeing in the dark. Living prosimians include bush babies, lemurs, lorises, and tarsiers.

End Show 32-3 Primates and Human Origins Slide 13 of 53 Copyright Pearson Prentice Hall Evolution of Primates Lorises and bush babies LemursTarsiers Primate ancestor Prosimians

End Show 32-3 Primates and Human Origins Slide 14 of 53 Copyright Pearson Prentice Hall Evolution of Primates Anthropoids Humans, apes, and most monkeys belong to a group called anthropoids, which means humanlike primates. This group split early in its evolutionary history into two major branches. These branches separated as drifting continents moved apart.

End Show 32-3 Primates and Human Origins Slide 15 of 53 Copyright Pearson Prentice Hall Evolution of Primates OrangutansChimpanzees Old World monkeys New World monkeys GibbonsGorillasHumans Anthropoids

End Show 32-3 Primates and Human Origins Slide 16 of 53 Copyright Pearson Prentice Hall Evolution of Primates One branch of anthropoids is the New World monkeys. New World monkeys: live almost entirely in trees. have long, flexible arms to swing from branches. have a prehensile tail, which is a tail that can coil around a branch to serve as a “fifth hand.”

End Show 32-3 Primates and Human Origins Slide 17 of 53 Copyright Pearson Prentice Hall Evolution of Primates The other group of anthropoids includes Old World monkeys and great apes. Old World monkeys live in trees but lack prehensile tails. Great apes, also called hominoids, include gibbons, orangutans, gorillas, chimpanzees, and humans.

End Show 32-3 Primates and Human Origins Slide 18 of 53 Copyright Pearson Prentice Hall Hominid Evolution Between 6 and 7 million years ago, the hominoid line gave rise to hominids. The hominid family includes modern humans. As hominids evolved, they began to walk upright and developed thumbs adapted for grasping. They also developed large brains.

End Show 32-3 Primates and Human Origins Slide 19 of 53 Copyright Pearson Prentice Hall Hominid Evolution Modern human

End Show 32-3 Primates and Human Origins Slide 20 of 53 Copyright Pearson Prentice Hall Hominid Evolution

End Show 32-3 Primates and Human Origins Slide 21 of 53 Copyright Pearson Prentice Hall Hominid Evolution The skull, neck, spinal column, hipbones, and leg bones of early hominid species changed shape in ways that enabled later hominid species to walk upright. Evolution of this bipedal, or two-foot, locomotion freed both hands to use tools. Hominids evolved an opposable thumb that enabled grasping objects and using tools.

End Show 32-3 Primates and Human Origins Slide 22 of 53 Copyright Pearson Prentice Hall Hominid Evolution Hominids displayed a remarkable increase in brain size, especially in an expanded cerebrum—the “thinking” area of the brain.

End Show 32-3 Primates and Human Origins Slide 23 of 53 Copyright Pearson Prentice Hall Hominid Evolution Early Hominids At present, the hominid fossil record includes these genera: Ardipithecus Australopithecus Paranthropus Kenyanthropus Homo

End Show 32-3 Primates and Human Origins Slide 24 of 53 Copyright Pearson Prentice Hall Hominid Evolution There are as many as 20 separate hominid species. This diverse group of hominid fossils covers roughly 6 million years. All are relatives of modern humans, but not all are human ancestors. Questions remain about how fossil hominids are related to one another and to humans.

End Show 32-3 Primates and Human Origins Slide 25 of 53 Copyright Pearson Prentice Hall Hominid Evolution Australopithecus An early hominid species, Australopithecus, lived from about 4 million to 1 million years ago. The structure of Australopithecus teeth suggests a diet rich in fruit.

End Show 32-3 Primates and Human Origins Slide 26 of 53 Copyright Pearson Prentice Hall Hominid Evolution The best known species is Australopithecus afarensis—based on a female skeleton named Lucy, who was 1 meter tall. Members of the Australopithecus species were bipedal and spent some time in trees.

End Show 32-3 Primates and Human Origins Slide 27 of 53 Copyright Pearson Prentice Hall Hominid Evolution Paranthropus The Paranthropus species had huge, grinding back teeth. Their diets probably included coarse and fibrous plant foods.

End Show 32-3 Primates and Human Origins Slide 28 of 53 Copyright Pearson Prentice Hall Hominid Evolution Recent Hominid Discoveries In 2001, a team had discovered a skull in Kenya. Its ear resembled a chimpanzee’s. Its brain was small. Its facial features resembled those of Homo fossils. It was put in a new genus, Kenyanthropus, which lived at the same time as A. afarensis.

End Show 32-3 Primates and Human Origins Slide 29 of 53 Copyright Pearson Prentice Hall Hominid Evolution Kenyanthropus platyopsHomo erectus

End Show 32-3 Primates and Human Origins Slide 30 of 53 Copyright Pearson Prentice Hall Hominid Evolution In 2002, paleontologists working in the desert in north-central Africa discovered another skull. Called Sahelanthropus, it is nearly 7 million years old. If it is a hominid, it would be a million years older than any hominid previously known. It had a brain like a modern chimp and a flat face like a human.

End Show 32-3 Primates and Human Origins Slide 31 of 53 Copyright Pearson Prentice Hall Hominid Evolution Sahelanthropus tchadensis

End Show 32-3 Primates and Human Origins Slide 32 of 53 Copyright Pearson Prentice Hall Hominid Evolution What is the current scientific thinking about hominid evolution?

End Show 32-3 Primates and Human Origins Slide 33 of 53 Copyright Pearson Prentice Hall Hominid Evolution Rethinking Early Hominid Evolution Researchers once thought that human evolution took place in steps, in which hominid species became gradually more humanlike.

End Show 32-3 Primates and Human Origins Slide 34 of 53 Copyright Pearson Prentice Hall Hominid Evolution Hominid evolution did not proceed by the simple, straight-line transformation of one species into another. Rather, a series of complex adaptive radiations produced a large number of species whose relationships are difficult to determine.

End Show 32-3 Primates and Human Origins Slide 35 of 53 Copyright Pearson Prentice Hall Hominid Evolution Millions of years ago

End Show 32-3 Primates and Human Origins Slide 36 of 53 Copyright Pearson Prentice Hall Hominid Evolution The hominid fossil record dates back 7 million years, close to the time that DNA studies suggest for the split between hominids and the ancestors of modern chimpanzees.

End Show 32-3 Primates and Human Origins Slide 37 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans Paleontologists still do not completely understand the history and relationships of species within our own genus. Other species in the genus Homo existed before Homo sapiens.

End Show 32-3 Primates and Human Origins Slide 38 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans The Genus Homo The first fossils in the genus Homo are about 2.5 million years old. These fossils were found with tools, so researchers called the species Homo habilis, which means “handy man.”

End Show 32-3 Primates and Human Origins Slide 39 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans 2 million years ago, a species called Homo ergaster appeared. It had a bigger brain and downward-facing nostrils that resembled those of modern humans. At some point, either H. ergaster or a related species named Homo erectus began migrating out of Africa through the Middle East.

End Show 32-3 Primates and Human Origins Slide 40 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans Out of Africa—But Who and When? Evidence suggests that hominids left Africa in several waves, as shown in the following diagram.

End Show 32-3 Primates and Human Origins Slide 41 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans

End Show 32-3 Primates and Human Origins Slide 42 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans It is not certain where and when Homo sapiens arose. One hypothesis, the multi-regional model, suggests that modern humans evolved independently in several parts of the world from widely separated populations of H. erectus.

End Show 32-3 Primates and Human Origins Slide 43 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans Another hypothesis, the out-of-Africa model, proposes that modern humans evolved in Africa between 200,000–150,000 years ago, migrated out to colonize the world, and replaced the descendants of earlier hominid species.

End Show 32-3 Primates and Human Origins Slide 44 of 53 Copyright Pearson Prentice Hall Modern Homo sapiens The story of modern humans over the past 500,000 years involves two main groups.

End Show 32-3 Primates and Human Origins Slide 45 of 53 Copyright Pearson Prentice Hall Modern Homo sapiens The earliest of these species is called Homo neanderthalensis. Neanderthals lived in Europe and Asia 200,000– 30,000 years ago. They made stone tools and lived in organized social groups. The other group is Homo sapiens—people whose skeletons look like those of modern humans.

End Show 32-3 Primates and Human Origins Slide 46 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans 50,000–40,000 years ago some populations of H. sapiens seem to have changed their way of life: They made more sophisticated stone blades and elaborately worked tools from bones and antlers. They produced cave paintings. They buried their dead with elaborate rituals.

End Show 32-3 Primates and Human Origins Slide 47 of 53 Copyright Pearson Prentice Hall The Road to Modern Humans About 40,000 years ago, a group known as Cro- Magnons appeared in Europe. By 30,000 years ago, Neanderthals had disappeared from Europe and the Middle East. Since that time, our species has been Earth’s only hominid.

End Show - or - Continue to: Click to Launch: Slide 48 of 53 Copyright Pearson Prentice Hall 32-3

End Show Slide 49 of 53 Copyright Pearson Prentice Hall 32-3 The ability to merge visual images from both eyes is called a.monocular vision. b.binocular vision. c.overlapping vision. d.color vision.

End Show Slide 50 of 53 Copyright Pearson Prentice Hall 32-3 Which of the following is true about hominid evolution? a.The development of a large brain happened before bipedal locomotion. b.There is a straight line of descent from the earliest hominid species to Homo sapiens. c.The genus Homo appeared before the genus Australopithecus. d.Hominid evolution took place as a series of adaptive radiations that produced a large number of species.

End Show Slide 51 of 53 Copyright Pearson Prentice Hall 32-3 The evolution of bipedal locomotion was important because it a.increased brain size. b.made it easier to see. c.freed both hands to use tools. d.allowed easier escape from predators.

End Show Slide 52 of 53 Copyright Pearson Prentice Hall 32-3 The multi-regional model hypothesizes that a.Homo sapiens evolved independently in several parts of the world. b.Modern humans evolved in Africa, then migrated to various parts of the world. c.Neanderthals produced cave drawings. d.Homo habilis descended from Homo erectus.

End Show Slide 53 of 53 Copyright Pearson Prentice Hall 32-3 The oldest known Homo sapiens skeletons are about a.6,000 years old. b.100,000 years old. c.3 million years old. d.30 million years old.

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