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1/21/2011 Evidence for Evolution • Darwin’s book (1859) Evidence for Evolution January 20th, 2011 Direct Observation – Over 500 pages – Contained Darwin’s reasoning, as well as many examples as well as many examples – Much new evidence in last 150 years Direct Observation • Example 2: – Drug‐resistant HIV • Example 1: – Guppies (Poecilia reticulata) in Trinidad 15 Generations • Highly variable male coloration • Females prefer bright males • Predators find brighter males more easily • Transplant drably colored males to a pool with low predator pressure • HIV uses reverse transcriptase • The drug 3TC substitutes for cytosine • Transcription is terminated Transcription is terminated Only adaptive when 3TC present Without 3TC, detrimental Natural selection doesn’t create, only selects Direct Observation Example 3:Birds introduced to islands MORPHOLOGICAL EVOLUTION OF BIRDS RECENTLY INTRODUCED TO ISLANDS RECENTLY INTRODUCED TO ISLANDS: PATTERNS OF DIVERSIFICATION Ph.D. Presentation 1 1/21/2011 Great Kiskadee on Bermuda • 200 introduced in 1957 • Supposed to eat lizards that eat beetles that eat scale insects that attack endemic tree scale insects that attack endemic tree • Quickly spread to all parts of the island Island Rule • Large‐bodied species get smaller on islands, small‐bodied species get larger • Mammals (Foster, 1964, 1965) • Other groups Oh (Lomolino, 2005), including birds (Clegg & Owens, 2002) • “Point of no change” estimated to be 70 to 120 grams for birds (Lomolino, 2005) © Claus Holzapfel © Howard B. Eskin The image cannot be display ed. Your computer may not hav e enough memory to open the image, or the image may hav e been corrupted. Restart y our computer, and then open the file again. If the red x still appears, y ou may hav e to delete the image and then insert it again. Island Rule Hypothesis • Kiskadee < 70 grams • Therefore, body size should increase on Bermuda Field Methods Bird Morphology 2 1/21/2011 Kiskadee Results Character Bermuda Trinidad % Larger Mass (grams) 62.7 ± 0.52 59.8 ± 0.69 4.9 Wing Chord 109.8 ± 0.42 108.1 ± 0.53 1.5 Head Length 55 49 ± 0.17 55.49 0 17 54 96 ± 0.21 54.96 0 21 10 1.0 Bill Depth 8.68 ± 0.04 8.53 ± 0.04 1.7 Bill Width 9.84 ± 0.06 9.50 ± 0.06 3.7 Tarsus Length 24.69 ± 0.12 24.26 ± 0.17 1.8 Kiskadees are larger on Bermuda Characters are heritable (0.2 < h2 < 0.6) Summary of Part 1 • Kiskadees on Bermuda follow the Island Rule • Part 2: Do other exotic birds? Museum Visits 3 1/21/2011 Island Rule Hypothesis • All birds I examined < 70 grams • Therefore, body size should increase on islands A fi ri ii ci a Asia South America i North America Europe Data Set • 38 exotic populations – Average of ~39 individuals/population Bermuda 4 Big Puerto Kauai Maui Oahu Mauritius Jamaica Island Rico 8 4 2 11 7 1 1 • Compared to individuals from native range – Average of ~28 individuals/population 7 increases : 3 decreases P = 0.34 Not the Island Rule, but... Summary of Part 2 Character # of Changes P value • May be losing Increase 19 Tail adaptations for <0.001 Length Decrease 2 dispersal ability, Increase 2 Wing <0.001 in favor of agility Chord in favor of agility Ch d Decrease 19 • Exotic birds on these islands do not follow the Island Rule • However, some characters (wing and tail) have evolved Culmen Length Increase 6 Decrease 10 Bill Depth Increase 4 Decrease 12 Increase 11 Decrease 4 Bill Width • Part 3: Diverged from source, maybe from each other? g , y 0.455 0.077 0.118 4 1/21/2011 b • 132 between‐island comparisons – 38 showed divergence Species % Diverging Character % Diverging 83 Mass 70 Wing Chord 43 50 3 islands x 6 characters = 18 between‐island comparisons 15 / 18 different = 83% Island Mass Tail Wing Length Chord Head Culmen Bill Length Length Depth Bill Width Tarsus Length Culmen Length 29 24 Bill Width 24 17 Tail Length 19 Bill Depth 17 Tarsus Length 11 Head Length 0 9 Maui 0 Oahu Big Island Summary of Part 3 • Exotic birds on Hawaii have diverged among islands • Variability in divergence among species and characters Acknowledgments • Julie Lockwood • My Committee (past and present): Rebecca Jordan, ) R b J d Peter Smouse, Dov Sax, & Peter Morin • Marsha Morin • Lockwood Lab: Ben, David, Julian, Orion, Karen, Bill, Tom, Alison, Oren • Field Tech: Matt Sileo • Friends: Amy, Elena, Jesse, Carrie, Aabir, Charlie, Holly, Dave, Kristen, Emilie, Ai, Wes, Zac, Brooke, Maria, Kenneth • Family • Funding: Teaching assistantships; nnGrant 8261‐07 5 1/21/2011 Acknowledgments The Fossil Record The Fossil Record • Deeper down into the earth, fossil organisms become less similar to modern organisms • Many species have become extinct • Deeper down into the earth, fossil organisms become less similar to modern organisms • Many species have become extinct Homologies • Similar characteristics due to shared ancestry Homologies • Similar characteristics due to shared ancestry Vestigial Structures 6 1/21/2011 Homologies Homologies • Homologies can be used to infer relatedness • Similar characteristics due to shared ancestry • Genetic Material – DNA, RNA – Not only same molecules N l l l Biogeography Convergent Evolution • Geographical distribution of life • Why are some species here but not there? • Natural Selection for similar ecology/life history • Unrelated species similar Peruvian Diving‐Petrel lochfitty Yellow‐throated Longclaw Eastern Meadowlark Jim “Jersey Birder” Razorbill Biogeography • Geographical distribution of life • Why are some species here but not there? Continental Drift Dispersal So is Darwinian Evolution “Just a Theory”? • Evolution is a Theory in the scientific sense – i.e., it has been repeatedly tested there is a lot of evidence supporting it • At At present, there are no other explanatory t th th l t theories with any scientific consensus Hawaii Amakihi Adelaide’s Warbler Endemic Found only in one location 7