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Evolution and Speciation

Delve into the fascinating world of evolution and speciation, exploring concepts like gene flow, genetic drift, mutations, and various types of speciation processes. Learn about patterns of evolution like gradualism, punctuated equilibrium, divergent evolution, convergent evolution, and co-evolution.

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Evolution and Speciation

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  1. Evolution and Speciation

  2. Gene Flow • Gene flow- allele frequencies are changed by organisms migrating in and out of populations

  3. Genetic Drift • Genetic drift- chance events that change allele frequencies (2 types) • Bottle Neck affect- a sudden random event in the environment can cause the population size to drop

  4. Genetic Drift • Founder affect- a small portion of the populations is isolated and starts a new gene pool

  5. Mutations • Mutations- random changes in DNA can change allele frequencies**

  6. Speciation -speciation- the evolution of a new species -species- organisms capable of interbreeding and producing healthy, fertile offspring

  7. Speciation Categories • Allopatric Speciation- speciation due to geographic isolation (most common) • Sympatric Speciation- speciation, despite living in the same geographic area

  8. Speciation -geographic isolation- when a physical barrier divides a population, creating a new species. (ex. Lava, earthquakes, etc)

  9. Speciation • Reduced Hybrid Fertility- Two species can mate, but offspring are not capable of reproduction. (sterile)

  10. Speciation • Behavioral Isolation- behaviors such as different courtship rituals prevent two species from mating

  11. Speciation -mechanical isolation- morphological differences prevent species from reproducing

  12. Speciation • Temporal Isolation- The time line of breeding prevents species from mating. They mate during different times of day or seasons.

  13. Speciation • Gametic Isolation – Incompatible gametes prevent two species from mating. (internal conditions vary, or gamete proteins don’t recognize one another)

  14. Speciation • Reduced Hybrid Viability- Two species can mate, but offspring are not healthy and die.

  15. Speciation • Hybrid Breakdown- Two species can mate, but when the Hybrids have offspring, the offspring are either sterile or unhealthy ( no grandkids)

  16. Patterns of evolution Gradualism- evolution happens slowly over time Punctuated equilibrium- evolution happens in quick bursts with long periods of no evolution in between.

  17. Patterns of Evolution Divergent evolution -(adaptive radiation)- species with a common ancestor become increasingly different (homologous)

  18. Patterns of Evolution Convergent evolution- unrelated species become similar (analogous)

  19. Patterns of Evolution Co-evolution- species evolve in response to each other

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