2. Regents Biology 2006-2007 Insect eaters Bud eater Seed eaters Cactus eater Warbler finch Tree finches Ground finches Chapter 15 Evolution: Evidence and Theory

3. Regents Biology Charles Darwin  Proposed a way how evolution works  How did creatures change over time?  by natural selection  Collected a lot of evidence to support his ideas  1809-1882  British naturalist

4. Regents Biology Robert Fitzroy Voyage of the HMS Beagle  Invited to travel around the world  1831-1836 (22 years old!)  makes many observations of nature  main mission of the Beagle was to chart South American coastline

5. Regents Biology Voyage of the HMS Beagle  Stopped in Galapagos Islands  500 miles off coast of Ecuador

6. Regents Biology Galapagos Recently formed volcanic islands. Most of animals on the Galápagos live nowhere else in world, but they look like species living on South American mainland. 800 km west of Ecuador

7. Regents Biology Many of Darwin’s observations made him wonder… Why? Why were these creatures found only on the Galapagos Islands? Darwin found…many unique species

8. Regents Biology present day Armadillos Darwin found: that creatures have changed over time Evidence that creatures have changed over time ancient Armadillo Darwin asked: Why should extinct armadillos & modern armadillos be found on same continent? Darwin found…clues in the fossils

9. Regents Biology present day Sloth Darwin found… more fossils Darwin asked: Why should extinct sloths & modern sloths be found on the same continent? (extinct) Giant ground sloth Darwin found: that creatures have changed over time Evidence that creatures have changed over time

10. Regents Biology Darwin found: Different shells on tortoises on different islands Darwin asked: Is there a relationship between the environment & what an animal looks like?

11. Regents Biology Darwin found… birds Darwin found: Many different birds on the Galapagos Islands. He thought he found very different kinds…

12. Regents Biology But Darwin found… a lot of finches Darwin was amazed to find out: All 14 species of birds were finches… Finch?Sparrow? Woodpecker? Warbler? But there is only one species of finch on the mainland! Darwin asked: If the Galapagos finches came from the mainland, why are they so different now?

13. Regents Biology The finches cinched it! Darwin found: The differences between species of finches were associated with the different food they ate. different beaks are inherited variations serve as adaptations that help birds compete for food these birds survive & reproduce pass on the genes for those more fit beaks over time nature selected for different species with different beaks

14. Regents Biology Relationship between species (beaks) & food

15. Regents Biology Darwin’s finches  Darwin’s conclusions  variations in beaks  differences in beaks in the original flock  adaptations to foods available on islands  natural selection for most fit  over many generations, the finches were selected for specific beaks & behaviors  offspring inherit successful traits  accumulation of winning traits: both beaks & behaviors  separate into different species

16. Regents Biology Warbler finch Woodpecker finch Small insectivorous tree finch Large insectivorous tree finch Vegetarian tree finch Cactus finch Sharp-beaked finch Small ground finch Medium ground finch Large ground finch Insect eaters Bud eater Seed eaters Cactus eater Warbler finch Tree finches Ground finches variation natural selection for best survival & reproduction From 1 species to 14 species…

17. Regents Biology  LaMarck  evolution by acquired traits  creatures developed traits during their lifetime  give those traits to their offspring  example  in reaching higher leaves giraffes stretch their necks & give the acquired longer neck to offspring  not accepted as valid Earlier ideas on Evolution

18. Regents Biology Darwin’s view of Evolution  Darwin  giraffes that already have long necks survive better  leave more offspring who inherit their long necks  variation  selection & survival  reproduction & inheritance of more fit traits

19. Regents Biology Evidence supporting evolution  Fossil record  shows change over time  Anatomical record  comparing body structures  homology & vestigial structures  embryology & development  Molecular record  comparing protein & DNA sequences  Artificial selection  human caused evolution

20. Regents Biology 1. Fossil record  Layers of rock contain fossils  new layers cover older ones  creates a record over time  fossils show a series of organisms have lived on Earth  over a long period of time

21. Regents Biology Fossils tell a story… the Earth is old Life is old Life on Earth has changed

22. Regents Biology Fossil of Archaeopteryx  lived about 150 mya  links reptiles & birds Today’s organisms descended from ancestral species Evolution of birds

23. Regents Biology Land Mammal ? ? ? ? Where are the intermediate fossils? Ocean Mammal Someone’s idea of a joke! But the joke’s on them!! Complete series of transitional fossils We found the fossil — no joke!

24. Regents Biology Evolution from sea to land  2006 fossil discovery of early tetrapod  4 limbs  Missing link from sea to land animals?

25. Regents Biology 2. Anatomical record Animals with different structures on the surface But when you look under the skin… It tells an evolutionary story of common ancestors

26. Regents Biology Compare the bones  The same bones under the skin  limbs that perform different functions are built from the same bones How could these very different animals have the same bones?

27. Regents Biology Homologous structures  Structures that come from the same origin  homo- = same  -logous = information  Forelimbs of human, cats, whales, & bats  same structure  on the inside  same development in embryo  different functions  on the outside  evidence of common ancestor

28. Regents Biology But don’t be fooled by these…  Analogous structures  look similar  on the outside  same function  different structure & development  on the inside  different origin  no evolutionary relationship Solving a similar problem with a similar solution How is a bird like a bug?

29. Regents Biology Analogous structures  Dolphins: aquatic mammal  Fish: aquatic vertebrate  both adapted to life in the sea  not closely related

30. Regents Biology Convergent evolution  3 groups with wings  Does this mean they have a recent common ancestor? Flight evolved 3 separate times — evolving similar solutions to similar “problems” Flight evolved 3 separate times — evolving similar solutions to similar “problems” NO! They just came up with the same answer!

31. Regents Biology Convergent evolution led to mimicry  Why do these pairs look so similar? Monarch male poisonous Viceroy male edible flybeemothbee Which is the fly vs. the bee? Which is the moth vs. the bee?

32. Regents Biology Vestigial organs  Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures? Because they used to walk on land!

33. Regents Biology Vestigial organs  Structures on modern animals that have no function  remains of structures that were functional in ancestors  evidence of change over time  some snakes & whales have pelvis bones & leg bones of walking ancestors  eyes on blind cave fish  human tail bone

34. Regents Biology Comparative embryology  Development of embryo tells an evolutionary story  similar structures during development all vertebrate embryos have a “gill pouch” at one stage of development

35. Regents Biology 3. Molecular record 1002030405060708090100110120 LampreyFrogBird Dog MacaqueHuman 32845 67 125  Comparing DNA & protein structure  everyone uses the same genetic code!  DNA  compare common genes  compare common proteins  compare common genes  compare common proteins number of amino acids different from human hemoglobin

36. Regents Biology Building “family” trees-Phylogeny Closely related species are branches on the tree — coming from a common ancestor

37. Regents Biology  How do we know natural selection can change a population?  we can recreate a similar process  “evolution by human selection” 4. Artificial selection “descendants” of wild mustard

38. Regents Biology Selective Breeding Humans create the change over time “descendants” of the wolf

39. Regents Biology Artificial Selection …and the examples keep coming!

40. Regents Biology Artificial Selection gone bad!  Unexpected consequences of artificial selection Pesticide resistance Antibiotic resistance

41. Regents Biology Insecticide resistance  Spray the field, but…  insecticide didn’t kill all individuals  variation  resistant survivors reproduce  resistance is inherited  insecticide becomes less & less effective

42. Regents Biology

43. 2006-2007 Any Questions??