Chapter 15: Theory of Evolution

1. Chapter 15: Theory of Evolution • Who was Charles Darwin? • How did he come up with the theory of Natural Selection & evolution?

2. How did Darwin’s visit to the Galapagos Islands (off the coast of South America) affect his thinking? http://www.geol.umd.edu/~jmerck/galsite/research/projects/fitz/currents.gif

3. How are unique organisms, like this Galapagos Island Tortoise, adapted to their environment? http://www.probe.org/galapagos/web-ray_tortoise.jpg

4. Harriet the Tortoise, carried to the Australian Zoo by Charles Darwin? • When Darwin’s ship, the Beagle, visited the Galapagos Islands in 1835, the crew collected dozens of the huge land tortoises. The adults were eaten but some small tortoises were taken on the ship around the world. • Harriet, mistakenly named “Harry” and thought to be male for over a century, was 330 lbs & a star at the Australian zoo. Many people believe she was one of Charles Darwin’s tortoises. • Harriet was at least 175 years old and recently died. http://www.conservationmagazine.org/2011/01/darwin%E2%80%99s-pet-tortoise/

5. Harriet with the “Crocodile Hunter”, who was one of many zoo keepers that cared for her over the years. msnbc.msn.com australiazoo.com.au

6. Why are there so many kinds of finches on the Galapagos Islands? Why are their beaks different? http://images.google.com/imgres?imgurl=http://www.thisviewoflife.org/evolution/finch.jpg&imgrefurl=http://www.thisviewoflife.org/evolution/finch. html&usg=__SDMg5Nbog4zBDG3nIjndQrC8oss=&h=440&w=519&sz=204&hl=en&start=5&um=1&itbs=1&tbnid=JySKhMK-oM_O0M:&tbnh=11 1&tbnw=131&prev=/images%3Fq%3Devolution%2Bfinches%26um%3D1%26hl%3Den%26tbs%3Disch:1

7. Why are there so many kinds of beetles?

8. What is Evolution? • Simply put: It is changes that occur in a population over time. http://softwarecreation.org/images/2008/evolution1.jpg

9. Evolution: a process by which organisms become more sophisticated over time and in response to its environment. (especially to a more advanced or mature stage) http://www.paulhina.com/hinablog-archives/duh.jpg

10. What Evolution is not: • Evolution does not & never did mean that man “descended from an ape”. • It means we are related to them. • Both man & apes had a common ancestor. http://www.cartoonstock.com/lowres/pha0127l.jpg

11. Individuals do not evolve -populations do • over time- in response to the environment.

12. Evolution • Is how scientists explain how all organisms, both living and extinct, are related. • Is considered a “cornerstone” theory of biology. • Consists of natural selection, microevolution & macroevolution.

13. There exists some controversy- we will address that issue in this chapter too. http://www.evoyage.com/What-is-Evolutions-Voyage-2.gif

14. Chapter 15 Definition of Evolution • Evolutionis the process of change in the inherited characteristics within populations over generations such that new types of organisms develop from preexisting types.

15. Ideas of Darwin’s Time • Most people of the time believed species were permanent & unchanging. • Scientific understanding of evolution began to develop in the 17 and 1800s • geologists and naturalists compared geologic processes & living & fossil organisms around the world.

16. Scientists began to study Rock layers & fossils • “strata”-the layers of rock • Inferred that oldest rock were made first & would be found on the bottom • Oldest rock would have oldest fossils

17. Ideas about Geology • Georges Cuvier–catastrophism- sudden catastrophic events caused mass extinction • Charles Lyell –uniformitarianism- same mechanisms that shaped Earth’s surface in the past continue to work today.

18. Catastrophism • sudden catastrophic events caused mass extinctions

19. Uniformitarianism • The same mechanisms that shaped Earth’s surface in the past continue to work today. evolution.berkeley.edu hweelin.tumblr.com

20. Jean Baptista Lamarck -Theory of Evolution -proposed that individuals coulddevelop traits during their lifetime, from experience or behavior-idea was: inheritance of acquired characteristics as a mechanism for evolution. Lamarck believed that the long necks of giraffes evolved as generations of giraffes reached for ever higher leaves. Lamarck also believed more simple life forms evolved into more complex life forms

21. Darwin was not the first naturalist to propose that species changed over time into new species—that life evolves. Even his own grandfather had discussed the concept of evolution.

22. Chapter 15 Darwin’s Voyage on the ship: HMS Beagle • Studied many things on the islands passed by boat. • he was so seasickhe wanted to get off the boat. • The things he saw were the basis for his life work.

23. Descent with Modification • BOOK: On the Origin of Species by Means of Natural Selection. • argued that descent with modification occurs • all species descended from common ancestors • natural selection is the mechanism for evolution.

24. Darwin’s Evolutionary Theory (which he called “natural selection” not “evolution”) -over many generations, natural selection causes characteristics of populations to change. -natural selection is responsible for evolution. -organisms with the best adaptations are more likely to survive & reproduce.

25. Natural Selection • The process by which individuals that are better adapted to their environment survive & reproduce more successfully than less well adapted individuals do. • A theory to explain the mechanism of evolution.

26. Individuals do not evolve -populations do • over time- in response to the environment.

27. Note the differences in evolution theory, Lamark vs Darwin. e-ducation.net

28. What is survival of the fittest? • It is NOT- “King of the Jungle”-with the meanest, biggest, most muscular animal killing all the smaller ones. • Example- 2 dogs- One is the perfect specimen- shiny fur, wins shows, smart, etc. & the other is small, ugly, mangy, living in the alley. The ugly dog visits every female dog in the county and reproduces many times, but the perfect dog never has puppies- • which dog will pass on his traits?

29. Ugly dog with lots of puppies = more successful than a beautiful dog with no offspring http://puppyintraining.com/wp-content/uploads/2008/12/howmany.jpg

30. Chapter 15 Natural Selection

31. Summary: 4 Main Parts of Darwin’s Reasoning • 1. Overproduction- more offspring are produced than can survive • 2. Genetic Variation- within a population, individuals have different traits • 3. Struggle to Survive- individuals must compete with each other to exist. • 4. Differential Reproduction-Organisms with the best adaptations to environment more likely to survive & reproduce.

32. Chapter 15 II. Section 9-2 Evidence of Evolution • Evolutionary theories are supported when several kinds of evidence support similar conclusions. Evidence of evolution can be found by comparing several kinds of data: A. The fossil record B. Biogeography C. Anatomy and Development D. Biological molecules.

33. Chapter 15 A. The Fossil Record 1. The Age of Fossils • Geologic evidence supports theories about the age and development of Earth. • Superposition- if rock layers have not been disturbed, lower strata is oldest. • Relative Age - compare to other fossils • Absolute Age - use radiometric dating 2. The Distribution of Fossils • Fossil record shows the types & distribution of organisms on Earth have changed over time. 3. Transitional Species • Fossils of transitional species show evidence of descent with modification.

34. Evidence of Whale Evolution Skeletons show sequence of transitional species that support the hypothesis that whales evolved from 4 legged land-dwelling mammals. Note: tiny, non-functioning hip bones in modern whales.

35. Chapter 15 B. Biogeography • Biogeography- the study of the locations of organisms around the world, provides evidence of descent with modification. • Example: Australia- The Marsupials there resemble rodents, wolves, cats, anteaters of other continents. May be evidence that these species evolved in isolation.

36. Biogeography Marsupials in Australia • current findings support a simple paleobiogeographic hypothesis, that indicates only a single migration from South America to Australia gave rise to all the Australian marsupials. • (South America, Antarctica, and Australia were connected in the South Gondwanan continent) blogs.discovermagazine.com boardgamegeek.com

37. Marsupials, a class of mammals with undeveloped young (live in mom’s pouch) • Of the 260 known marsupial species, just a couple live in the Americas, and the rest live in Australia and the Australasian islands that surround it. • There are no living marsupial species native to Europe, Asia, or Africa. Placental mammals out-competed with them millions of years ago. The only one in North America is the opossum! http://www.bigsiteofamazingfacts.com/how-many-marsupial-species-live-in-europe-asia-or-africa- besides-native-australia-and-how-did-they-evolve

38. Chapter 15 C. Anatomy and Physiology • Analogous structures -are similar in function but have different evolutionary origins. (Does not show evidence for evolution) • Homologous structures have a common evolutionary origin. (shows evidence of evolution) • Vestigial structure- structures that are reduced in size & function- but may have been complete & functional in an organism’s ancestor. (shows evidence of evolution)

39. Chapter 15 Forelimbs of Vertebrates The organisms show Homologousparts- Anatomical structures that have related structure, even if the function Is different. Shows a relatedness- used to show a common ancestor.

40. Homologousstructures Comparing the structural features found in different organisms reveals a basic similarity. example is the forelimb of mammals - Although function is quite different, they are similar structurally.

41. Analogous structures • We must look at structures that look & function the same but are not derived from the same embryonic tissue. • Analogousfeatures do not show recent, related ancestry.

42. Vestigial structures • Features which serve no useful function any longer in the organism. • Examples: the pelvis bone in the whale, tailbone & appendix in humans, pelvis & leg bones in some snakes, etc

43. Organism may become more similar or more different over time. • Divergent Evolution- 2 species become more and more dissimilar. • Convergent Evolution- Species which have different ancestors, but have become more similar

44. Divergent evolution: • example Sharks that had a common ancestor have become more different than each other over time. • Especially rays & sharks. elasmo-research.org

46. D. Biological Molecules-Chromosomes & Macromolecules • Provide the most precise information about the evolution of life • (This is now the most important evidence! DNA!) • DNA, RNA & Proteins are Macromolecules that are compared between organisms. • Can indicate a common evolutionary history. • Example- the number of differencesin amino acids is a clue to how long ago 2 species “Diverged”

47. Hemoglobin Comparison

48. Proteins indicate degree of relatedness. Differences - Amino Acids in Protein Cytochrome C • (From Atlas of Protein Sequence and Structure, 1967-68 by Margaret O. Dayhoff

49. What is a Phylogenic Tree ? • A family tree that shows evolutionary relationships thought to exist among organisms. • Is a hypothesis about the relationships & is subject to change as more is learned.

50. A phylogenic tree of mammals: Branches show they are related to each other. Closer branches show closer cousins. Farther apart on the branches indicate more distant relationships. The trunk shows a common ancestor!