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Human Evolution.

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Presentation on theme: "Human Evolution."— Presentation transcript:

1 Human Evolution

2 Classification Hierarchy
Kingdom Animal Phylum Chordate Class Mammal Order Primates Family Hominids Genus Homo Species Sapiens

3 Important Vocabulary Paleoanthropologist
Scientist who studies fossil evidence of human evolution. Homininds Group that includes humans and their immediate ancestors.

4 Background It is very rare to find a complete skeleton of a fossilized hominid. Scientists need to look at many different things to try and piece together the puzzle of human evolution.

5 Background Cont’d When hominid fossils are found, several important characteristics can help determine origin and lifestyle of the species. Did organism walk upright? Curvature of spine, position where spine attaches to skull and shape of pelvis Brain size? Examine skull fragments Diet? Wear and tear on fossilized teeth How and where did it live? Fossils found in same area & environment found

6 Primates 2 Divisions of Primates Characteristics:
1. Anthropoid primates 2. Prosimean primates Characteristics: Flat Nails (no claws) Prehensile hands and feet (grasping) Color vision and depth perception

7 Anthropoid Primates Include: Brain size Opposable thumbs
marmosets Monkeys Apes Humans Brain size Large relative to their body size Opposable thumbs Similar dental formula number and arrangement of teeth

8 HUMANS Bipedalism – Ability to walk on 2 feet
Aligned toes = Bipedalism Enlarged brain =Vertical face Areas for speech in the brain S- shaped spine Bowl-shaped pelvis

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10 Prosimean primates Include: Lemurs Lorises Tarsiers

11 Tarsier Skeleton

12 Hominids Hominids include humans and extinct humanlike primates
The oldest known hominid fossils are between 6 and 7 million years old First fossils found in Africa

13 Australopithecus NOT ancestral to modern humans!
Oldest known genus of hominids Lived more than 4 million years ago Knee joints- Allow bipedalism! Australopithecus anamensis Australopithecus afarensis – believed to have given rise to: A. africanus A. robustus A. boisei more than 1 million years ago NOT ancestral to modern humans!

14 Australopithecus vs. Modern
Australopithecus, 4-3 myrs ago Modern human Chimpanzee

15 A. africanus !

16 A. boiser !

17 Discovery of Lucy! Fossils of nearly half complete early hominid Australopithecus afarensis suggests hominids became bipedal before their brains began to dramatically enlarge

18 Ardipithecus ramidus Recent discovery Not clear whether it was bipedal
4.4 million years old

19 Existence of hominid species not ancestral to modern humans implies…
Hominid phylogenetic tree is very branchy in appearance Representing species died out, leaving no descendants.

20 Early Members of the genus Homo H. habilis & H. erectus
Ancestors to modern humans Larger brains than australopithecines May have had speech Started to develop tools Homo erectus Homo habilis

21 FIGURE 17-15 Representative hominid tools
(a) Homo habilis produced only fairly crude chopping tools called hand axes, usually unchipped on one end to hold in the hand. (b) Homo ergaster manufactured much finer tools. The tools were typically sharp all the way around the stone; at least some of these blades were probably tied to spears rather than held in the hand. (c) Neanderthal tools were works of art, with extremely sharp edges made by flaking off tiny bits of stone. In comparing these weapons, note the progressive increase in the number of flakes taken off the blades and the corresponding decrease in flake size. Smaller, more numerous flakes produce a sharper blade and suggest more insight into toolmaking, more patience, finer control of hand movements, or perhaps all three.

22 Cranial Comparisons Homo Erectus Neanderthal Homo Sapiens

23 Neanderthals For years, the thinking among anthropologists was that homo sapiens, being superior to Neanderthal man, ran him off the planet. More recently, that view has been discarded and the picture become more complicated. For one thing, Neanderthals may have mixed with the ancestor of modern man, which means that we could be carrying Neanderthal genes.

24 Reconstructed Neanderthal skull
characterized by prominent heavy brow ridges and week chin

25 Cro-Magnons Cro-Magnons coexisted with Neanderthals in Europe and the Middle East for as many as 50,000 years Cro-Magnons had domed heads, smooth brows, and prominent chins 30,000-year-old Cro-Magnon artifacts include: Bone flutes Ivory sculptures Evidence of elaborate burial ceremonies

26 Cro-Magnon Cave Painting

27 Homo sapiens Evolved about 800,000 years ago A) Neanderthals
Were early Homo sapiens They may be ancestral to modern humans OR They may have died out and been replaced by modern humans

28 Some hypotheses: 1. some anthropologist think H. sapiens evolved in PARALLEL from populations of H. erectus all over the world. (interbreeding) 2. some anthropologists propose that H. sapiens DESCENDED from H. erectus in Africa and then dispersed across Earth.

29 Evolution of Modern Humans

30 Human Evolution

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33 Piltdown Man (1912) Charles Dawson fake 1953 preceding Neanderthals
*

34 Waves of Hominid Emigration
Two hypotheses have been proposed for the evolution of Homo sapiens “African replacement” hypothesis Also called Out of Africa, Recent-African-Origin “Multiregional origin” hypothesis

35 “African Replacement” Hypothesis
Members of the genus Homo made repeated long-distance migrations out of Africa beginning 1.8 million years ago H. sapiens emerged from Africa about 150,000 years ago and spread across the Near East, Europe, and Asia The dispersing H. sapiens populations replaced all other hominids

36 Evolution of Modern Humans

37 FIGURE 17-18a Competing hypotheses for the evolution of Homo sapiens
(a) The "African replacement" hypothesis suggests that H. sapiens evolved in Africa, then migrated throughout the Near East, Europe, and Asia, displacing the other hominid species that were present in those regions.

38 “Multiregional Origin” Hypothesis
H. erectus emerged from Africa 1.8 million years ago and spread across the Near East, Europe, and Asia Continued migrations and interbreeding occurred among widespread H. erectus populations Regional populations of H. erectus evolved into H. sapiens

39 Evolution of Modern Humans

40 FIGURE 17-18b Competing hypotheses for the evolution of Homo sapiens
(b) The "multiregional" hypothesis suggests that populations of H. sapiens evolved in many regions simultaneously from the already widespread populations of H. erectus.


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