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WHAT IS A SPECIES?. A population of group of populations whose members have the potential to interbreed with one another in nature to produce viable, fertile offspringThis biological species concept emphasizesAbility to productively interbreed within the speciesReproductive isolation from closel
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1. THE ORIGIN OF SPECIES
2. WHAT IS A SPECIES? A population of group of populations whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring
This biological species concept emphasizes
Ability to productively interbreed within the species
Reproductive isolation from closely related species
3. REPRODUCTIVE ISOLATION Any factor impeding two species from producing viable, fertile offspring contributes to reproductive isolation
Species are often separated by multiple barriers
4. REPRODUCTIVE ISOLATION Prezygotic barriers
Habitat isolation
Behavioral isolation
Temporal isolation
Mechanical isolation
Gametic isolation Postzygotic barriers
Reduced hybrid viability
Reduced hybrid fertility
Hybrid breakdown
5. REPRODUCTIVE ISOLATION Habitat isolation Two species living in separate habitats within the same area may encounter each other rarely e.g., Two species of garter snakes (genus Thamnophis) occur in the same areas, but one is primarily aquatic and the other is primarily terrestrial