Human Evolution

1. Human Evolution BIO 2343 Oklahoma City Community College Dennis Anderson

2. Animal Connection • Humans share many traits with animals • We are most similar to apes • Same 206 bones • All but 3 of 650 muscles the same • DNA is 98% the same • Same blood types Albino Gorilla

3. Why are we so similar to apes? • Modern apes and modern man share a common ancestor who lived about 5 to 6 million years ago

4. Does the idea of human evolution from animals contradict a belief in God? • Many scientists of all religious faiths believe in both. • Some people feel evolution contradicts the literal interpretation of the Bible.

5. Earths Position in the Universe • 400 years ago the general public thought that the earth was the center of the universe • Sun revolves around the earth • The earth does not move

6. Galileo and Corpernicus • Demonstrated scientific evidence that the sun is at the center of our solar system and the earth moves around the sun

7. Galileo and the Church • Religious leaders felt the heliocentral theory (sun at the center) was a direct contradiction to the literal interpretation of the Bible • Galileo found guilty of heresy

8. Copernican System (Heliocentral Theory) • Did not destroy peoples belief in God • Public now accepts the overwhelming evidence for the heliocentral theory

9. Theory of Evolution • Science has overwhelming evidence that all life is constantly evolving

10. Natural Selection • One mechanism of evolution • Main concepts of natural selection • Overproduction of offspring • Inherited variation in offspring • Competition • Best adapted in a given environment survive and reproduce to increase their kind • They are naturally selected

11. Overproduction of Offspring • Elephants (very slow reproductive rate) • If all the offspring of one elephant pair survive and all their offspring survive then: • 750 years = 19,000,000 elephants • 1200 years = Enough elephants to cover the earth! • Beetles • A handful that weighs 10 mg each • 82 weeks • 61,000,000,000,000,000,000,000 ton • The weight of the earth!

12. Variation of Offspring • Offspring of the same parents are different from each other

13. Competition • Since more individuals are born than can survive for an extended period of time, they compete for resources • Food • Living space • Mates

14. Best adapted to a given environment are selected to survive • Brown bears • Adapted to survive in Oklahoma • Polar bears • Adapted to survive in Alaska

15. Sequence of Human Evolution • Hundreds of fossils have been found • Some of the major fossils will be discussed in this presentation

16. Australopithicus afarensis • 3.5 million years ago • Nicknamed Lucy • Walked upright • Small brain • Skeleton human like • Feet • Pelvis • Upright stance

17. Comparative Anatomy Lucy Gorilla Human • Gorilla pelvis adapted for knuckle walking • Human pelvis adapted for upright walking • Lucy’s pelvis very similar to human pelvis

18. Knuckle Walking • Requires an elongated pelvis and long arms

19. Lucy’s pelvis allowed her to walk like a human instead of an ape.

20. Fossilized Footprints • Footprints left when a a pair of Australopithecines walked in the ash of a recently erupted volcano

21. Lucy Chimp Skull Anatomy • Thick brow ridges like a chimpanzee • Cranial capacity 400 cc. Chimp 350 cc. • Teeth similar to human teeth

22. Lucy: A Transitional Fossil • Transitional fossil shows characteristics of two kinds of animals • Represent the transition from one organism to another • Ape characteristics • Skull • Cranial capacity • Human characteristics • Walked upright • Feet • Pelvis

23. Australophithicus africanus • 2.8 million years ago • Cranial capacity 460 cc

24. Homo habilis • Cranial capacity 630 cc • Flatter face than Australopithecines • Used tools • Nicknamed handy man

25. Homo erectus • 1.8 million to 35,000 years ago • 1,000 cc cranial capacity • Large brow ridges • Sloping forehead • More advanced tools than H. habilis

26. Homo erectus • Skeleton very similar to modern man • Used fire • Traveled • Fossils found in Africa, Europe, China, Indonesia

27. Homo neanderthalensis • 135,000 to 25,000 years ago • Cranial capacity up to 1750 cc • Larger than modern man • No chin • Sloping forehead • Buried dead with tools and flowers

28. Homo sapiens • 200,000 years ago to present • Photo is a skull 100,000 years old • 1400 cc cranial capacity • Vertical forehead • Pronounced chin

29. Modern Homo sapiens • Small front teeth • Small brow ridges • Rounded cranium

30. Homo neanderthalensis Australopithicus afarensis Australopithicus africanus Homo erectus Homo habilis Common ancestor Modern apes Sequence of Human EvolutionOne of several possibilities Homo sapiens

31. Evolution of Skull • Cranial capacity increases for a larger brain • Face become flatter • Brow ridges become smaller • Forehead becomes higher • Chin develops

32. Tools used to learn about our evolutionary past • Study of fossils • Comparing DNA • Comparing chromosomes • Comparing protein sequences

33. Paleontology • Study of fossils • Allows us to see anatomical similarities between us and organisms that lived in the past • Allows us to see how our ancestors have changed over time

34. Comparing DNA • Human DNA compared to: • Chimpanzee 99% same • Gorilla 97.7% same • Orangutan 96.3% same • Another human 99.9% same

35. Comparing Chromosomes • All apes have 48 chromosomes • Chromosome bands between human (H) and chimpanzee (C) 99% the same • Translocation of two ape chromosomes formed human chromosome 2

36. Inversions • Human and chimp chromosomes • Inversion between p14.1 and q14.1 • 9 total inversions in human vs. chimp

37. Comparing Protein Sequences • Many proteins in all of man are identical • Organ transplants require similar proteins in the donor and the recipient • A sibling or parent is often the best source for an organ transplant

38. Which would be the closest protein match for an organ transplant?Assuming all are alive and healthy. • A persons father • A persons great grandfather • A persons 10th great grandfather

39. Molecular Clock • The further you go back in time, the more proteins (and DNA) are different. • Differences in protein sequences and DNA can be used to estimate time when two species shared a common ancestor

40. Related Organisms • Close similarity of protein sequences indicates close relationship

41. Cytochrome C • Protein used to release energy from food • 104 amino acids • 20 of the amino acids occupy the same position in all eukaryotes

42. Comparison of Human Cytochrome C • 100 amino acids different in tuna fish • 12 amino acids different in a horse • 8 amino acids different in a kangaroo • 1 amino acid different in a monkey • Identical to chimpanzee

43. Mitochondrial DNA • Only inherited from mother • Mutates faster than nuclear DNA • Lacks repair enzymes

44. Mitochondrial DNA • Studied in several different human populations • Greatest diversity found in African population • Therefore the oldest population • Molecular clock

45. Mitochondrial Eve • Mother of all humans • She may have lived about 200,000 years ago in Africa

46. Native American Origin • Four Rare mtDNA haplotypes are found in Native Americans • The same haplotypes are found in Mongolia and China

47. Mitochondrial DNA • Four Rare mtDNA haplotypes are found in Native Americans • The same haplotypes are found in Mongolia and China

48. Neanderthal Man • Mitochondrial DNA studies indicate he was not a direct human ancestor • Contemporary species with early Homo sapiens • H. sapiens out competed H. neaderthalensis

49. Eugenics • “Improvement” of the human race • Attempt to direct human evolution • Not allow unfit to reproduce • By 1956 58,000 people in USA sterilized for being feeblemindedness, criminality and insanity

50. American Eugenics Society • Founded in 1923 • Lobbied for IQ tests of immigrants • Lobbied to not allow immigrants from countries not from northern Europe