Populations become seperated by a physical barrier and the evolve reproductive barriers
Most common
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
What is secondary contact?
When species reconverge after speciation
How can you tell if a vicarian event ocured by looking at a phylogeny tree
Closest relative will be in different geographic area
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
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
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)
What does a hybrid zone indicate?
Primary differenctiona Find slide
What is Sympatric speciation?
No geographic separation
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)
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