1 / 29

Macroevolution

Macroevolution. Biology. Speciation. Review: Microevolution. Changes in genetic frequencies for a trait, in a population. H.W.E. Conditions. Our equations are great for: Finding allele frequencies: p + q = 1 Finding genotype frequencies: p 2 +2pq + q 2 = 1

dorothygriffith
Download Presentation

Macroevolution

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Macroevolution Biology

  2. Speciation

  3. Review: Microevolution • Changes in genetic frequencies for a trait, in a population.

  4. H.W.E. Conditions • Our equations are great for: • Finding allele frequencies: p + q = 1 • Finding genotype frequencies: p2 +2pq + q2 = 1 • Showing microevolution if values change over time • When would allele frequencies not change over time?

  5. H.W.E. Conditions • No Mutations • No new genotypes/phenotypes • Very large population size • No minor population disruptions (genetic drift) • Isolation from other populations • No immigration/emigration (gene flow) • Random Mating • No picky females choosing one allele over another • No natural selection • No environmental pressures selecting one allele over another

  6. Macroevolution (Speciation) • Formation of a new species

  7. Definition of a Species • Population of interbreeding organisms

  8. Ensatina salamanders • http://video.pbs.org /video/1300397304/

  9. Isolation Mechanisms

  10. Isolation Mechanisms • Isolate two populations, isolate two gene pools: • Mutations in one pop. will not transfer to the other • Ex: House mouse of Madeira, Portugal

  11. Habitat Isolation • Populations are geographically separated.

  12. Behavioral Isolation Populations respond to different mating cues

  13. Temporal Isolation • Populations breed during different times

  14. Hybrid Sterility • Hybrid offspring is not fertile

  15. Biological Species Concept • Defines a species as a population or group of populations whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring, but who cannot successfully interbreed with members of other species

  16. Limitations to BSC • Does not account for • Asexually reproducing species: bacteria • Fossil species: Trilobite

  17. Evolution Since Darwin

  18. Studying the Unobservable • Direct Observation • Fossil Record • Comparing Structures • Molecular Analysis

  19. 1. Direct Observation • Pathogen Resistance: • Head Lice • Salmonella • Escherichia coli • Pseudomonas aeruginosa • Streptococcus pyogenes • Clostridium difficile, etc…

  20. 1. Direct Observation • Male guppies have variable colors • Colors attract mates • Colors attract predators • After many years of study: • Ponds with many predators produce drab ♂ • Ponds with few predators produce colorful ♂

  21. 1. Direct Observation • Ensatina Salamanders

  22. 2. Fossil Record • Shows the evolution of a species over time

  23. 2. Fossil Record • Homonid sp. fossils

  24. 2. Fossil Record

  25. 3. Comparing Structures • Homologous Structure: • Similar body structures of different organisms • Show evolutionary relationships

  26. 3. Comparing Structures • Vestigial Structures: • Structures with NO known functions • Show remnants of evolutionary past

  27. 3. Comparing Structures • Homo sapiens • Appendix: previous stomach • Coccyx: previous tail • Wisdom teeth: previous herbivore • Ear muscles: previous limited head mobility • Plica semiluneris: previous nictitating eyelid • Goosebumps: (hair standing up to scare off predators) • Palmer grasp reflex: (infants grasp mother after birth)

  28. 4. Molecular Analysis • Compare similarities in genetics • DNA nucleotides • Chromosomes • Protein sequences

  29. 4. Molecular Analysis • Humans and Chimpanzees have ~98% of the same genes & a common ancestor

More Related