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 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: VvAndromedavV, 2008, Wikimedia Commons
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=MK6nlsOZpuU
• 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
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: ArthurWeasley, 2007, Wikimedia Commons• Building Tiktaalik Video: http://www.youtube.com/watch?v=MkOy1XU0cbY• And, for fun, enjoy the music video: http://www.youtube.com/watch?v=B9h1tR42QYA
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: Richard001, 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
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)
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