2. AP Biology 2006-2007 Evolution by Natural Selection

3. AP Biology LaMarck  Organisms adapted to their environments  through acquired traits  change in their life time  Use & Disuse organisms lost parts because they did not use them — like the missing eyes & digestive system of the tapeworm  Perfection with Use & Need the constant use of an organ leads that organ to increase in size — like the muscles of a blacksmith or the large ears of a night-flying bat  transmit acquired characteristics to next generation

4. AP Biology Charles Darwin  1809-1882  British naturalist  Proposed the idea of evolution by natural selection  Collected clear evidence to support his ideas  http://www.pbs.org/wgbh/evolution/ library/11/2/real/e_s_2.html http://www.pbs.org/wgbh/evolution/ library/11/2/real/e_s_2.html

5. AP 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 Darwin’s finches  Differences in beaks  associated with eating different foods  adaptations to foods available on islands

6. AP Biology A Reluctant Revolutionary  Returned to England in 1836  wrote papers describing his collections & observations  long treatise on barnacles  draft of his theory of species formation in 1844  instructed his wife to publish this essay upon his death  reluctant to publish but didn’t want ideas to die with him

7. AP Biology And then came the letter…. Alfred Russel Wallace a young naturalist working in the East Indies, had written a short paper with a new theory. He asked Darwin to evaluate his theory and pass it along for publication. Then, in 1858, Darwin received a letter that changed everything…

8. AP Biology The time was ripe for the idea! Your words have come true with a vengeance… I never saw a more striking coincidence…so all my originality, whatever it may amount to, will be smashed. To Lyell—

9. AP Biology Voyage: 1831-1836 November 24, 1859, Darwin published “On the Origin of Species by Means of Natural Selection”

10. AP Biology (5) Over long periods of time, and given a steady input of new variation into a population, these processes lead to the emergence of new species Essence of Darwin’s ideas (1)Variation exists in natural populations (2) Many more offspring are born each season than can possibly survive to maturity (3) As a result, there is a struggle for existence - competition - competition (4) Characteristics beneficial in the struggle for existence will tend to become more common in the population, changing the average characteristics of the population - adaptations - adaptations

11. AP Biology Natural Selection  Darwin referred to all of these factors together as natural selection  variation  production of more offspring than can survive  competition  for food, for mates & nesting spots, to escape predators  differential survival based on traits  successful traits = adaptations

12. AP Biology LaMarckian vs. Darwinian view  LaMarck  in reaching higher vegetation giraffes stretch their necks & transmits the acquired longer neck to offspring  Darwin  longer-necked giraffes survive better & leave more offspring who inherit their long necks  genes

13. AP Biology You work out, baby comes out like this!! -biologynlk Not quite Lamarck!!! http://www.youtube.com/playlist?list=PL5270149AB73 2F0FB

14. AP Biology 2007-2008 Evidence of Evolution by Natural Selection Dodo bird

15. AP Biology 2007-2008 Evolution is "so overwhelmingly established that it has become irrational to call it a theory." -- Ernst Mayr What Evolution Is 2001 Professor Emeritus, Evolutionary Biology Harvard University (1904-2005)

16. AP Biology Evidence supporting evolution  Fossil record  transition species  Anatomical record  homologous & vestigial structures  embryology & development  Molecular record  protein & DNA sequence  Artificial selection  human-caused evolution  http://www.pbs.org/wgbh/evolution/library/11/2/real/e_s_3. html http://www.pbs.org/wgbh/evolution/library/11/2/real/e_s_3. html

17. AP Biology Fossil record  Layers of sedimentary rock contain fossils  new layers cover older ones, creating a record over time  fossils within layers show that a succession of organisms have populated Earth throughout a long period of time

18. AP Biology Anatomical record  Homologous structures  similarities in characteristics resulting from common ancestry

19. AP Biology Homologous structures  Forelimbs of human, cats, whales, & bats share same skeletal structures  similar structure  similar embryological development  different functions  evidence of common ancestor  branched off from common 4-limbed ancestor

20. AP Biology Homologous structures  Similar structure  Similar development  Different functions  Evidence of close evolutionary relationship  recent common ancestor

21. AP Biology Analogous structures  Separate evolution of structures  similar functions  similar external form  different internal structure & development  different origin  no evolutionary relationship Solving a similar problem with a similar solution Don’t be fooled by their looks!

22. AP Biology Convergent evolution  Flight evolved in 3 separate animal groups  evolved similar “solution” to similar “problems”  analogous structures

23. AP Biology Convergent evolution  Fish: aquatic vertebrates  Dolphins: aquatic mammals  similar adaptations to life in the sea  not closely related Those fins & tails & sleek bodies are analogous structures!

24. AP Biology Parallel Evolution  Parallel, but separate, evolutionary paths  filling similar ecological roles in similar environments, so similar adaptations were selected  but are not closely related marsupial mammals marsupial mammals placental mammals placental mammals

25. AP Biology Vestigial organs  Modern animals may have structures that serve little or no function  remnants of structures that were functional in ancestral species  evidence of change over time  some snakes & whales show remains of the pelvis & leg bones of walking ancestors  eyes on blind cave fish  human tail bone

26. AP Biology Vestigial organs  Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures?

27. AP Biology Comparative embryology  Similar embryological development in closely related species  all vertebrate embryos have similar structures at different stages of development  gill pouch in fish, frog, snake, birds, human, etc. http://www.pbs.org/wgbh/nova/evolution/guess- embryo.html

28. AP Biology Molecular record 0255075100125 0 25 50 75 100 Millions of years ago Horse/ donkey Sheep/ goat Goat/cow Llama/ cow Pig/ cow Rabbit/ rodent Horse/cow Human/rodent Dog/ cow Human/ cow Human/kangaroo Nucleotide substitutions  Comparing DNA & protein structure  universal genetic code!  DNA & RNA  compare common genes  cytochrome C (respiration)  hemoglobin (gas exchange) Closely related species have sequences that are more similar than distantly related species  DNA & proteins are a molecular record of evolutionary relationships Closely related species have sequences that are more similar than distantly related species  DNA & proteins are a molecular record of evolutionary relationships

29. AP Biology Comparative hemoglobin structure Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans 1002030405060708090100110120 LampreyFrogBird Dog MacaqueHuman 32845 67 125

30. AP Biology Artificial selection  A rtificial breeding can use variations in populations to create vastly different “breeds” & “varieties” “descendants” of the wolf “descendants” of wild mustard

31. AP Biology Natural selection in action  Insecticide & drug resistance  insecticide didn’t kill all individuals  resistant survivors reproduce  resistance is inherited  insecticide becomes less & less effective