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Evolution Part 2 BIOL 1407. Evolutionary Fitness Darwin’s concept: An organism is more “fit” if it has more offspring that successfully reproduce compared.

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Presentation on theme: "Evolution Part 2 BIOL 1407. Evolutionary Fitness Darwin’s concept: An organism is more “fit” if it has more offspring that successfully reproduce compared."— Presentation transcript:

1 Evolution Part 2 BIOL 1407

2 Evolutionary Fitness Darwin’s concept: An organism is more “fit” if it has more offspring that successfully reproduce compared to others in the population Photo Credit: Eigenes Werk, 2008, Wikimedia Commons

3 Evolutionary Fitness More fertile offspring = Higher Fitness Photo Credit: Larry Ridenhour, Bureau of Land Management, 2005

4 Evolutionary Fitness Fitness ≠ Survival Fitness ≠ Stronger Fitness ≠ Healthier Fitness ≠ Smarter Fitness ≠ Better Photo Credit: Jeff Kubina, 2004, Wikimedia Commons

5 Evolutionary Fitness FITNESS = MORE OFFSPRING! Photo Credit: B.navez, 2007, Wikimedia Commons

6 Evolutionary Fitness Fitness comes down to leaving more copies of your genes in future generations than others Photo Credit: Harlequeen, 2007, Wikimedia Commons

7 Inclusive Fitness Inclusive fitness = your fitness + fitness of family members Directly and indirectly leaving copies of your genes Photo Credit: Ltshears, 2006, Wikimedia Commons

8 Florida Scrub Jays Young jays help their parents raise siblings May forego reproducing for up to five years Some never get to reproduce Photo Credit: VvAndromedavV, 2008, Wikimedia Commons

9 Florida Scrub Jays Still have fitness  their genes are present in the siblings they helped raise

10 Adaptations Characteristics that increase fitness in a particular environment Can be: –Structures –Biochemical reactions –Behaviors –Anything under genetic control that provides some sort of advantage

11 Adaptations A successful adaptation in one environment may not be successful in a different environment. Photo Credit for desert: Jörn Napp, 2007, Wikimedia Commons Photo Credit for Prairie: Katy Prairie Conservancy, 2008, Wikimedia Commons

12 Walrus Adaptation Thick blubber is an adaptation for cold Arctic ocean conditions. In warmer waters, they overheat and die Photo Credit: NOAA, 2005, Wikimedia Commons

13 Adaptation Example: Railroad Vine Often seen on Texas beaches Live on sand dunes –Constantly shifting sand –Little water –High salt levels. Photo Credit: South Siesta Key Beach Restoration

14 Railroad Vine Long runners stabilize sand Soil accumulates around roots Stabilizes dune Photo Credit: UNK Vieques Field Trip 2008

15 Example: Railroad Vine Other plants move onto stable dunes Railroad vines cannot compete successfully in other environments. Photo Credit: National Park Service, Padre Island,

16 The Great Potoo Night: Fly and catch insects Day: sleep on branches Camouflage used for protection Video: K6nlsOZpuU K6nlsOZpuU Photo Credit: Tom Davis

17 The Great Potoo Adaptations: –Plumage coloration –Body position –Eyelids Photo Credit: Tom Davis

18 Evidences of Evolution Fossil Record Biogeography Comparative Anatomy Comparative Embryology Molecular Evidence

19 Fossils A window into evolutionary history Only way to see what some organisms looked like in the past Photo Credit: Doyle Cross at Texas Memorial Museum, UT Austin

20 Pterosaur Fossil Photo Credit: Doyle Cross at Texas Memorial Museum, UT Austin

21 Pterosaur Wing Details Photo Credit: Doyle Cross at Texas Memorial Museum, UT Austin

22 Fossil Record Gaps in fossil record In cases of major structural changes: –Evolve in step-by-step fashion? –Evolve suddenly (one step)? With gaps, you can’t be sure

23 Transitional Fossils Demonstrate a step-by-step transition from an ancestral form to modern forms Photo Credit for Tiktaalik rosae: ArthurWeasley, 2007, Wikimedia Commons Building Tiktaalik Video: And, for fun, enjoy the music video:

24 Whale Transition Fossils: Pakistan, Egypt, North America Four-legged terrestrial ancestors  Whales Hind limbs: Legs  Vestigial bones Front limbs: Legs  Flippers Ankle bones: Similar to hippos & relatives

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26 Biogeography Study of distribution of organisms: –Where are they located? –Why are they there? Horseshoe Crabs Distribution Map Credit: University of Delaware College of Marine and Earth Studies and the Sea Grant College Program

27 An Example: Ratites Large, flightless birds Southern Hemisphere Photo Credit: Richard001, 2007, Wikimedia Commons

28 Living Ratites Ostrich (Africa) Rheas (South America) Emus (Australia) Cassowaries (Australia and Papua New Guinea), Kiwis (New Zealand) Photo Credit: Paul IJsendoorn, 2007, Wikimedia Commons

29 Extinct Ratites Moas (New Zealand) Elephant Bird (Madagascar) Photo Credit for Moa drawing: Frederick William Frohawk, 1907, Wikimedia Commons

30 Evolution of Ratites Common ancestor evolved on Gondwana Gondwana  Southern Continents Picture Credit: USGS image from Wikimedia Commons

31 Comparative Anatomy Similarities and differences in structure Photo Credits: Vassil (2007, Crocodile eye) and Rainer Zenz (2006, Cuttlefish eye), Wikimedia Commons

32 Homologous Structures Similar due to shared ancestry

33 Analagous Structures Similar lifestyles but different ancestry

34 Comparative Embryology Similarities and differences in development

35 Comparative Embryology Some similarities only visible during early development Completely obscured in later stages Photo Credits: Fir0002, 2008, Wikimedia Commons (Chick); Michele Cross, 2007 (Human baby)

36 Comparative Embryology Click on this link and play the video: Photo Credit: Dr. Katharine Lewis, University of Cambridge, School of the Biological Sciences,

37 Molecular Evidence Comparisons of protein or DNA sequences Can show evolutionary relationships among widely divergent organisms Protein Sequence Credit: Miguel Andrade, 2006, Wikimedia Commons

38 Molecular Evidence Distinguish homologous from analogous structures Read about Giant Pandas at: /naturalhistory/phylogen /naturalhistory/phylogen Photo Credit: Jeff Kubina, 2004, Wikimedia Commons

39 Molecular Evidence

40 The End Unless otherwise specified, all images in this presentation came from: Campbell, et al Biology, 8 th ed. Pearson Benjamin Cummings.


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