Genetics - Species and speciation

  1. What is speciation and how does it relate to phylogeny tree?
  2. What are the modes of speciation?
    • Allopatric "other place"
    • Parapatric "beside place"
    • Sympatric
    • Hybridization
  3. What is Allopatric speciation?
    • Populations become seperated by a physical barrier and the evolve reproductive barriers
    • Most common
  4. What are two types of Allopatry + examples?
    • Vicariant: pop divided into two widespread populations by a physical barrier - no dispersal - result = 2 large pop
    • ex: freshwater fish and snapping shrimp (land bridge formation)
    • Peripatric: A small colony disperses from a widespread population to a new area and evolves reproductive isolation Physical barrier - dispersal - 2 small pop.
    • Usually caused by genetic drift/founder effect
  5. What is secondary contact?
    When species reconverge after speciation
  6. How can you tell if a vicarian event ocured by looking at a phylogeny tree
    Closest relative will be in different geographic area
  7. Why are elephant seals and example of peripatric speciation?
    • Hunted to samll number
    • small colony near Mexico - Founder effect
    • very small genetic diversity (population bottleneck)
    • -conservation issue
  8. What is Parapatric Speciation?
    • Strong selection causes a continuous population to diverge
    • Populations are contifuous
    • No physical barrier (gene flow) speciation between niches within ecosystem
  9. What is a Hybrid Zone?
    When a species diverges, but populations come back together. The area the two pop meet is the hybrid zone (secondary contact)
  10. What does a hybrid zone indicate?
    Primary differenctiona Find slide
  11. What is Sympatric speciation?
    No geographic separation
  12. What is Hybridization?
    • Model of speciation
    • Two parental species hybridize and produce offspring that can breed with each other, but are reproductively...
    • Much more common in plants (rare in animals)
  13. Speciation by polyploidy is caused by __?__.
    • Errors in mitosis or meiosis resulting in diploid gametes instead of normal haploid gametes.
    • Individuals with diploid gametes mate with each other and produce polyploid offspring
    • Resulting individuals can not breed with progenitors (parents), but can breed with each other
  14. Know summary slide
Card Set
Genetics - Species and speciation
Genetics - Species and speciation