Cornell Notes
Topic/Objective:
Name: tasha
Class/Period:
Date: 1/15/21
Essential Question:
Questions:
Notes:Reproductive Isolation
• Reproductive Isolation: the inability of formerly interbreeding organisms
to produce offspring
Reproductive isolation can occur through disruptive selection.
Two Types:
Prezygotic- Differences in mating times;
Postzygotic- death / sterility of offspring
Pre zygotic Isolation
• Reduce the chance of hybrid formation ( no new alleles are formed)
Geographic isolation( diff. places)
Ecological isolation(utilize diff. resources)
Behavioral Isolation (diff. mating rituals)
Temporal Isolation(Mating at diff. seasons)
Mechanical isolation( structural differences)
Prevention of gamete fusion( gametes function poorly)
• Developmental ( poor development of embryo)
• Hybrid unviability (adults do not survive in nature
Hybrid sterility ( hybrids are sterile/reduced fertility
Rates of Speciation
• Punctuated Equilibrium: a theory that speciation may occur during brief
periods of rapid genetic change
• Gradualism: a theory that speciation may occur through a gradual change
of adaptations
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