Hominid Evolution: On The Origin of Humans.

1. Hominid Evolution:On The Origin of Humans.

2. Questions to answer: • What is a human? • What is a hominid? • What were early humans (hominids) like? • How long have humans (hominids) been around? • Where - and when - did modern humans (Homo sapiens) originate? • How have we changed? • How did we come to populate the entire earth?

3. What is a hominid? • Any human-like species, including us. • Bipedal (walks on two legs). • Intelligent (large brain, uses tools).

4. Hominids are not the same as modern apes. • Modern apes like chimpanzees, gorillas, orangutans are not bipedal. • Modern apes do not have a large brain case compared to ours. • Modern apes do not make tools. • However, chimpanzees are our closest relative - our DNA is 98% similar to theirs!

5. There have been at least a dozen different species of hominids over the last five million years or so.

6. Since the first hominid fossils and artifacts were found, we have found literally hundreds of others.

7. Anthropologists compare the skulls, teeth, bones, and tools.Together they begin to show our family tree - how we evolved to who we are today.Notice that most species have gone extinct - there are a lot of “dead ends”.

8. We are still not exactly sure when the first bipedal hominids evolved, but an amazing discovery in 1974 proved that hominids were bipedal a lot earlier than previously believed.Her name was Lucy.

9. “Lucy In The Sky With Diamonds.” • Discovered in Ethiopia in 1974. • Dated at 3.2 million years old! • 40% of her skeleton was found. • Only four feet tall. • Bipedal for certain. She walked upright. • Her scientific name is Australopithecus afarensis, a distant ancestor to us, Homo sapiens.

10. An even more impressive fossil was found in 1978, but there were no bones to it at all.Huh? This discovery proved that there were bipedal hominids even earlier than Lucy.

11. The Laetoli Footprints • 3.6 million years old. • Even older than Lucy. • Clearly bipedal. • Also showed that these early hominids walked together.

12. Bipedalism The A. afarensis foot bone is shown with a human foot indicating where it would be positioned.

13. Upright posture permitted many kinds of changes: • Hands were freed- tools, weapons, food gathering • Walking/running on two legs- travel great distances, follow game • Visibility of surroundings was greater

14. Upright posture permitted many kinds of changes: • Pelvis changed from long form (ape) to short robust form (human) • Curvature of spine developed • Birth canal became more narrow

16. So who were the “first” hominids? We still are not sure, but we have found more fossil fragments as early as five million years ago.

17. And when did our species - Homo sapiens - first evolve?And how did we come to dominate the earth?

18. It is important to remember that there were several species in the genus Homo that came before Homo sapiens. • Homo habilis is the earliest fossil discovered so far. (2.3 million years old) • It means “handy man”. • Homo habilis used very simple tools.

19. Homo erectus was a serious toolmaker and a fine hunter. Evidence also indicates that they were the first to use fire.

20. Fossils of several other species in the genus Homo have also been found. • Homo ergaster. • Homo heidelbergensis. • The most famous is Homo neanderthalensis (Neanderthal Man). • Neanderthal Man lived in Europe. • They too went extinct. • Probably lived side-by-side with Homo sapiens. • Possibly interbred with them.

21. And then there is…

22. Homo sapiens.Anatomically modern humans. • Oldest fossils found so far are perhaps 195,000 years old. • Found in Africa (also in Ethiopia).

23. Does that mean we all come from Africa?

24. Yes!And recently, DNA analysis has proven this.

25. We are all Africans. • DNA testing of thousands of humans today, using a simple saliva test kit, has created a “map” of human migration since modern humans first left Africa 80,000 years ago.

26. We now have an excellent “road map” of how humans evolved from Africa and migrated to populate the rest of the earth. This evidence matches the fossils and fills in the gaps.

27. And if we follow the path of our mitochondrial DNA back to the beginning, somewhere in Africa…

28. We find that all humans alive today, including us, descended from a SINGLE FEMALE.Scientists have called her “Eve”.

29. From Lucy to “Eve”. • Using fossils, artifacts, and now even our DNA, we are slowly getting a good picture of our own hominid evolution.

30. Brain Cavity Size

31. Brain Size Species Timing (mya) Size (cc) Ancestral hominid 4 350 Australopithecus 3-4 450 Homo habilis 2-1.6 650-750 Homo erectus 1.5 850-1100 Homo sapiens 0.1 1400 Rapid evolution relative to other organisms.

32. Homo sapiens Homo erectus Homo habilis Australopithecus africanus chimpanzee

33. Problems with the human design: • wisdom teeth- jaws are small and too many teeth • childbirth- birth canal small, heads large • back problems- curvature of back poses strain, more vulnerable to injury • hernias- upright posture puts more strain • varicose veins- return of blood to heart puts strain on veins

34. Problems with the human design: • hemorrhoids- veins more vulnerable to congestion, impedes blood flow to lower intestine and anal sphincter • milk leg- pregnant woman have arteries to legs pinched • foot problems- too small to bear body wt. • learning to walk- children learn to walk gradually and changes in the body structure must accompany the learning process

35. African Origins Model