Speciation Flashcards
Speciation is defined as what?
The process by which actually or potentially interbreeding natural populations
1) accumulate genetic differences
2) produce two lineages
Allopatric speciation:
Speciation that occurs when two populations become
geographically isolated from each other for a long period of time.
Parapatric speciation:
Speciation that occurs when two populations occupy
different geographic areas but always have a band of overlap between them.
Sympatric speciation:
Speciation that occurs when subpopulations of a species are not geographically isolated but occupy slightly different microhabitats.
Speciation may be nearly instantaneous due to:
Polyploidy
Prezygotic barriers:
Prevent fertilization of the egg from ever occurring.
Postzygotic barriers
Interfere with the viability of the resulting offspring.
Habitat isolation:
Species occupy different habitats within the same area
Temporal isolation:
Species breed in different years, seasons, or times of day
Behavioral isolation:
Differences in courtship rituals that enable individuals to find mates.
Mechanical isolation:
Mating may be attempted but is not possible due to
morphological differences
Gametic isolation:
Sperm from one species may not be able to survive in the reproductive track of females from another species or may not be biochemically capable of binding with or penetrating the egg’s membrane.
Examples of postzygotic barriers:
Hybrids experience:
1) reduced vitality
2) reduced fertility
3) breakdown over time
Biological species concept:
Reproductive isolation (can’t reproduce)
Morphological species concept:
Similar body structures
