Supporting Evidence for Evolution

1. Supporting Evidence for Evolution

2. Evolution evidence does not make sense unless there is an awareness of differences between living organisms process of organizing and classifying organisms into certain groups by their differences is called taxonomy Taxonomy comes from a root Greek word meaning “order” or “arrangement”

3. Taxonomic Classification: biological classification • classification; placing of similar objects into similar groups • Biological classification organizes all living organisms • Structure, DNA, cell type, complexity, etc.

4. History of Classification • developed by Swedish scientist Carolus Linnaeus in the 18th century • Designed to have a universal naming system • binomial nomenclature- organism's scientific name is comprised of a combination of two terms: genus and species • scientific name for humans- Homo sapiens

5. Reason for universal naming system Common name: PUMA, MOUNTAIN LION, COUGAR Scientific Name: Felis concolor Name this animal

6. Classification DOMAIN • Domain is the most broad while species is the most specific • Mnemonic: • dear king phillip came over for good soup

8. Classification

9. Structures, functions and genetics help support the theory of evolution *Other supporting evidence: fossil records, relative/absolute dating Convergent evolution vs Divergent evolution Homologous Structures Analogous Structures Vestigial Structures Embryology Genetic similarities Atavisms

10. Convergent evolution • These traits can be called analogous traits Convergent evolution: unrelated pathways to different species develop similar traits. Similar traits develop due to similar environmental pressures.

11. Analogous Traits Different structures with the same function

12. Divergent evolution • opposite of convergent evolution • related pathways can develop different traits over time: • Natural selection, sexual selection, genetic barriers and mutation drive these changes. • enough small changes accumulate in closely related but isolated populations, speciation might occur

13. Homologous Traits Same structure but different function characteristics that derive from shared common ancestry

14. Vestigial Structures (vestigial organ) • Many organisms possess vestigial structures • no apparent function, however; they resemble structures their presumed ancestors had • Structures were once important • Through evolutionary change the structures became useless

15. Vestigial structure examples Humans-possess a complete set of muscles for wiggling their ears human appendix is believed to be vestigial; it represents the terminal part of the cecum

16. Vestigial Structures Boa constrictors have hip bones and rudimentary hind legs

17. Vestigial Structures Manatees, a type of aquatic mammal, have fingernails on their fins (which evolved from legs)

18. Vestigial Structures Baleen whale, which contains pelvic bones, as other mammal skeletons do, even though such bones serve no known function in the whale.

19. Do Now Questions 1. Which organism has the closest relationship to Panthera leo? How do you know? Felis concolor Panthera tigris Equus caballus Canis lupus 2. Which format for scientific name is correct? danaus plexippus c. Danaus Plexippus Danaus plexippus d. Danaus plexippus

20. Embryology • study of embryos • formation, development, structure and function • An embryo is an organism in its early stages of development

21. Comparative Embryology • Comparing stages of early development from very different animals provides evidence for commonality

22. Genetic Similarities (molecular homology) • Technology has allowed us to examine the DNA and protein structures/patterns from any organism in existence • Comparing different species DNA can undercover similarities and differences • How closely related are these organisms?

23. Genetic Similarities • protein: hemoglobin- • Who are humans closest relative using hemoglobin testing?

24. How similar are we when comparing DNA? Another human? ~99.9% A chimpanzee? ~97-98% A mouse? ~90% A fruit fly? ~45% Yeast? ~25%

25. Genetic Similarities

26. Genetic Similarities • Humans chromosomes vs. chimpanzees chromosomes • Chromosome #2 fused

27. Atavism • reappearance of a trait or characteristics in an organism that is typical of an ancestral form (appearing trait has been absent from modern organism for many generations) • usually due to mistake in reading DNA • Expressing “junk DNA” • Atavism can be seen in many different organisms

28. Atavisms

29. Human Atavisms

30. Cladogram A tree-like diagram which shows the evolutionary relationship between organisms

31. Reading and constructing a cladogram X X X X X X X X X X cat gorilla salamander Opposable thumbs lamprey hair jellyfish legs vertebrae

32. What can a cladogram tell you? time • Common ancestor • Closest relative • Distant relative Speciation event

33. Punctuated equilibrium and gradualism

35. Do Now Fill in the chart and create a cladogram.

36. Who is classified as a primate? an animal order (classification) including lemurs, tarsiers, monkeys, apes and human beings

37. Primate Cladogram

38. New fossil evidence! • Oldest primate ancestor was thought to be 60 mya • New primate ancestor found- absolute dating puts its age at around 85 mya BBC news: http://news.bbc.co.uk/2/hi/science/nature/1935558.stm

39. Earliest primate found thus far (85 myo)

40. Closer look at an ape cladogram See video**

41. Comparing humans to great apes…

42. Comparing humans to great apes Primate Hand

43. Comparing humans to great apes Genetic comparison: Humans and chimpanzees are ~97% similar in their genetic composition Large difference- # of chromosomes See video**

44. What happened after the speciation event where chimps and humans diverged? • Environmental conditions that lead to chimpanzees: tree-dwellers • Environmental conditions that lead to humans: ground-dwellers

45. The modern human was not always this way… See video**

46. Modern human skull

47. Evolution of humans

48. Evolution of humans

49. Lucy (3.2mya) and Ardi(4.4mya) *Oldest fossils all found in Africa*

50. Species are arranged according to the earliest date of fossils found so far ( a couple of recent discoveries are not shown). The red lines end because fossils have not been found any older for that species. **Note the overlap of time for species** The oldest fossils in the evolution of humans have only been found on the continent of Africa, no where else.