Evolution Part 2 BIOL 1407 Evolutionary Fitness Darwins

Evolution Part 2 BIOL 1407

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

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

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

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

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

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

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: Vv. Andromedav. V, 2008, Wikimedia Commons

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

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

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

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

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

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

Example: Railroad Vine • Other plants move onto stable dunes • Railroad vines cannot compete successfully in other environments. • Photo Credit: National Park Service, Padre Island, http: //www. nps. gov/archive/pais/pphtml/photogallery. html

The Great Potoo • Night: Fly and catch insects • Day: sleep on branches • Camouflage used for protection • Video: http: //www. youtube. com/watch? v=M K 6 nls. OZpu. U • Photo Credit: Tom Davis

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

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

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

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

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

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

Transitional Fossils • Demonstrate a step-by-step transition from an ancestral form to modern forms • • • Photo Credit for Tiktaalik rosae: Arthur. Weasley, 2007, Wikimedia Commons Building Tiktaalik Video: http: //www. youtube. com/watch? v=Mk. Oy 1 XU 0 cb. Y And, for fun, enjoy the music video: http: //www. youtube. com/watch? v=B 9 h 1 t. R 42 QYA

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

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 http: //www. ocean. udel. edu/horseshoecrab/history/pastpresent. html

An Example: Ratites • Large, flightless birds • Southern Hemisphere • Photo Credit: Richard 001, 2007, Wikimedia Commons

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

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

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

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

Homologous Structures • Similar due to shared ancestry

Analagous Structures • Similar lifestyles but different ancestry

Comparative Embryology • Similarities and differences in development

Comparative Embryology • Some similarities only visible during early development • Completely obscured in later stages Photo Credits: Fir 0002, 2008, Wikimedia Commons (Chick); Michele Cross, 2007 (Human baby)

Comparative Embryology • Click on this link and play the video: http: //www. pbs. org/wgbh/evolution/library/04/2/l_042_02. html Photo Credit: Dr. Katharine Lewis, University of Cambridge, School of the Biological Sciences, http: //www. pdn. cam. ac. uk/staff/lewis/

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

Molecular Evidence • Distinguish homologous from analogous structures • Read about Giant Pandas at: http: //www. giantpandaonline. org /naturalhistory/phylogen • Photo Credit: Jeff Kubina, 2004, Wikimedia Commons

Molecular Evidence

The End Unless otherwise specified, all images in this presentation came from: Campbell, et al. 2008. Biology, 8 th ed. Pearson Benjamin Cummings.