WHAT IS EVOLUTION ?

1. WHAT IS EVOLUTION?

2. Evolution is a change in gene pool over time.It also is the idea that new species develop from earlier species, sometimes referred to as “descent with modification”

3. FAQ: Isn’t evolution only a theory?

4. It is a fact in the respect that yes, it has indeed occurred and is occurring on a daily basis.It is a theory in the respect that scientists disagree on the details of how it occurred.

5. Remember what a theory in science is - a well-substantiated explanation of some aspect of the natural world that can incorporate facts, inferences, and tested hypotheses* (not a hunch or guess) *(National Science Foundation)

6. Scopes Trial in Dayton, TN (1925)

8. Next Battleground: Dover, PA

9. Dover trial began on Monday: Sept. 26, 2005

10. The Scope and Limitations of Science Are More Than An Academic Issue The Scope and Limitations of Science Are More Than An Academic Issue

11. What is the evidence of evolution? 1) The Fossil Record 2) A Universal Genetic Code 3) Shared Amino Acid Sequences 4) Transitional Fossils 5) Vestigial Structures 6) Daily observations of evolution of microbes 7) Homologous Structures 8) Shared Sequences of DNA ; over 98% similarity in chimps, Chr 2

12. The Fossil Record and Transitional Fossils

13. Evidence - A transitional fossil linking past and present

14. The Branched Evolution of Horses

15. Evidence - Molecular Data and the Evolutionary Relationships of Vertebrates

16. Evidence - Homologous Structures: anatomical signs of descent with modification

17. Homologous Embryos

18. Evidence - Evolution of insecticide resistance in insect populations

19. Evidence - The evolution of fruit fly (Drosophila) species on the Hawaiian archipelago

20. Vestigial Organs/Structures – are reduced in size and no longer used by the organism. • appendix • thirteenth rib (vs 12) • wisdom teeth • rudimentary ear muscles • coccygeal (tail) vertebrae • body hair

21. Vestigial Structures(continued) • Palmaris Muscle – for climbing and is missing in 11% of humans • Pyramidalis Muscle – more than 20% of humans lack this relic from marsupials • Subclavius Muscle – in the shoulder region; useful for tetrapods

22. Vestigial Structures(continued) • Third Eyelid – a common ancestor of birds and mammals may have had a membrane for protecting the eye • Plantaris Muscle – for grasping has disappeared in 9% of humans; in legs of primates • Neck Ribs – appear in 1% of the population

23. FAQ: Are you going to teach us that we are descendants of apes? • No, That’s an inaccurate concept- ion of evolutionary theory. We have the closest common ancestry with the great apes

24. A Molecular Test of Common Ancestry Chromosome Numbers in the Great Apes: Human (Homo) 46 Chimpanzee (Pan) 48Gorilla (Gorilla) 48Orangutan (Pogo) 48 Testable prediction: If these organisms share a common ancestor, that ancestor had 48 chromosomes (24 pairs)

25. Chromosome Numbers in the great apes (Hominidae): Human (Homo) 46Chimpanzee (Pan) 48Gorilla (Gorilla) 48Orangutan (Pogo) 48 Fusion Homo sapiens Inactivated centromere Telomere sequences Ancestral Chromosomes Centromere Telomere Testable prediction:If these organisms share a common ancestor, that ancestor had 48 chromosomes (24 pairs)

26. Chromosome Numbers in the great apes (Hominidae): Human (Homo) 46Chimpanzee (Pan) 48Gorilla (Gorilla) 48Orangutan (Pogo) 48 Hillier et al (2004) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.

27. “Chromosome 2 is unique to the human lineage of evolution, having emerged as a result of head-to-head fusion of two acrocentric chromosomes that remained separate in other primates. The precise fusion site has been located in 2q13–2q14.1 (ref. 2; hg 16:114455823 – 114455838), where our analysis confirmed the presence of multiple subtelomeric duplications to chromosomes 1, 5, 8, 9, 10, 12, 19, 21 and 22 (Fig. 3; Supplementary Fig. 3a, region A). During the formation of human chromosome 2, one of the two centromeres became inactivated (2q21, which corresponds to the centromere from chimp chromosome 13) and the centromeric structure quickly deterioriated (42).” Homo sapiens Inactivated centromere Telomere sequences Hillier et al (2004) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.

28. FAQ: If we have a common ancestor with apes, why are there still apes?

29. FAQ: Doesn’t “believing” or “accepting” evolutionary theory mean you don’t believe in God? No, most mainstream religions accept modern evolutionary theory it premises

30. FAQ: Why can’t we learn creationism and evolution? Should “equal time” be devoted to both?

31. FAQ: Isn’t evolution always improving organisms? Not always, but there is a drive towards a particular phenotype. Evolution is a result of the interactions between species and their current environments. If these conditions change, an apparent evolutionary trend may cease or reverse itself.

32. FAQ: Why is it that important anyway?

33. Evolution is a central unifying theme incorporating: - molecular (DNA)biology-cellular biology-genetics-taxonomy - physiology

34. Evolution Is Biology’s Unifying Principle Evolution Is Biology’sUnifying Principle

35. “Nothing in biology makes sense except in the light of evolution.”Theodosius Dobzhansky, 1973

36. How is evolution both a fact and a theory? What is meant by the word, “theory”?

37. What was the last major court case dealing with teaching evolution in schools? What was the ruling? List two major pieces of evidence that demonstrate evolution has occurred.

38. Place the following events in chronological order from first to most recent using “Pacing Geologic Time” • evolution of reptiles • evolution of mammals • evolution of birds • evolution of amphibians • first flowering plants

39. Know These in Chronological Order: • evolution of eukaryotes • first multicellular life • earliest fish • first amphibians • first reptiles • first dinosaurs • first mammals • earliest birds • first flowering plants • early primates • earliest humans

40. Calculate the percentage of time that humans have been on the earth. • 2) The fossil record supports the • theory that all multicellular • evolved within the past ______ million years.

41. Classify a snake from its proper domain down to its class. Organisms that start their lives in water and move onto land are called ….

42. Pacing Geologic Time Answers • 3500 million years ago (3.5 billion) • 3) 2800 million (3500 mill – 700 mill) • 5) The geologic events are further • apart • 6) 3.5 million X 100 = .07% • 4600 million • 7) amphibians, reptiles, mammals, • birds.

43. After Dr. Miller’s presentation you should • be able to discuss the following: • 1) what occurs in artificial selection • 2) The change in the anatomy of the whale over millions of years • 3) the change in cranial capacity of humans • 4) molecular data to support our common • ancestry with the great apes

44. 2) From the textbook reading, give examples of the following: a. vestigial organs b. homologous structures