Biology, 9th ed, Sylvia Mader Chapter 32 Chapter 32 Human Evolution Human Evolution
Evolution of Early Hominids Evolution of Later Hominids Outline Evolution of Primates Mobile Limbs Binocular Vision Evolution of Early Hominids Evolution of Later Hominids Evolution of Early Homo Modern Humans Human Variation
The evolution of primates is characterized by trends towards: Mobile limbs Grasping hands A flattened face Binocular vision A large, complex brain, and A reduced reproductive rate
Primate Diversity
Mobile Limbs Hands and feet Most primates have flat nails Sensitive pads on the undersides of fingers and toes Many also have both an opposable big toe and thumb Mobile limbs and clawless opposable digits allow primates to freely grasp and release tree limbs
Evolution of Primate Hand
Binocular Vision Stereoscopic vision Depth perception Allows primates to make accurate judgments about distance and position of adjoining tree limbs
Binocular Vision
Primate Characteristics Opposable thumb Nails instead of claws Single births Binocular vision Expanded, complex brain Emphasis on learned behavior
Surviving anthropoids are classified into three superfamilies Evolution of Primates Prosimians were the first type of primate to diverge from the human line Surviving anthropoids are classified into three superfamilies New World monkeys Old World monkeys Hominoids
Evolution of primates
Proconsul is believed ancestral to hominids Evolution of Hominids Proconsul is believed ancestral to hominids Phylogenetic tree indicates humans are most closely related to African apes Genetic changes used as a molecular clock to measure relatedness of different groups Last common ancestor appears to have lived about 7 mya
Monkey Skeleton Compared to Proconsul Skeleton
Skeletal differences between humans and apes largely because: Hominids Hominid fossils: Must have an anatomy suitable for standing erect and walking on two feet Bipedalism Skeletal differences between humans and apes largely because: Humans are bipedal, while Apes are quadrupedal
Adaptations for Standing
Australopithecines Australopithecines: Evolved and diversified in Africa 4 mya Possibly a direct ancestor of humans Southern Africa Australopithecus africanus Eastern Africa Australopithecus afarensis
Human Evolution
Australopithecus afarensis
Evolution of Early Homo Homo habilis Dated between 20 an 19 mya May be ancestral to modern humans Skulls suggest portions of the brain associated with speech were enlarged Ability to speak may have led to hunting cooperatively and the advent of culture
Homo erectus and similar fossils Found in Africa, Asia, and Europe Dated between 19 and 03 mya Larger brain and flatter face than Homo habilis Much taller than previous hominids Thought to have first appeared in Africa and then migrated into Asia and Europe First hominid to use fire
Homo ergaster
Evolution of Modern Humans Most researchers believe Homo sapiens evolved from Homo erectus Multiregional Continuity Hypothesis Similar evolution occurred in many different places Out-of-Africa Hypothesis H. sapiens evolved from H. erectus only in Africa, and thereafter migrated to Europe
Evolution of Modern Humans
Neanderthals Neanderthal (H. neanderthalensis) skeletons were first discovered in Germany’s Neander Valley Skeletons date back 200,000 years Massive brow ridges with protruding nose, jaws, and teeth Heavily muscled Culturally advanced Manufactured variety of tools
Neandertals
Oldest fossils to be designated H. sapiens Cro-Magnons Oldest fossils to be designated H. sapiens Modern humans who entered Asia and Europe from Africa 100,000 years ago Made advanced stone tools Accomplished hunters Hunted cooperatively First to have language
Cro-Magnons
Comparative study of mitochondrial DNA Human Variation Hypothesized that human variations evolved as adaptations to local environmental conditions Bergmann’s Rule - Animals in colder regions of their range have a bulkier body build Allen’s Rule - Animals in colder regions of their range have shorter limbs, digits, and ears Comparative study of mitochondrial DNA Suggests human populations have a common ancestor no more than a million years ago
Ethnic Groups
Evolution of Early Hominids Evolution of Later Hominids Review Evolution of Primates Mobile Limbs Binocular Vision Evolution of Early Hominids Evolution of Later Hominids Evolution of Early Homo Modern Humans Human Variation
Biology, 9th ed, Sylvia Mader Chapter 32 Ending Slide Chapter 32 Human Evolution Human Evolution