Speciation Flashcards
what is speciation?
evolutionary formation of new species
Also called macro evolution
What are species?
Members of groups or populations
what is a reproductive isolating mechanism?
Any behavioural structural or biochemical trait that prevents species from reproducing together
what is pre-zygotic barriers
Prevention of mating, or fertilization of eggs
what is post zygotic barriers?
Prevent zygotes from becoming fertile
what are pre-zygotic isolating mechanisms
behaviour isolation
Habitat isolation
Temporal isolation
Mechanical isolation
Gamete isolation
explain Behavioural Isolating Mechanism
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Behaviours that prevent interbreeding between closely related species
explain, habitat, isolating mechanisms and example
Two species living in same region, but different habitats
garter snake
What is temporal isolating mechanism?
Barriers to mating caused by
timing differences
explain, mechanical isolating mechanism
differences in reproductive organs make them incompatible
what is gamete isolating mechanism
gamete from different species rarely fuse to make zygote
in nature, is it rare for sperm of one species to successfully fertilize an egg of another?
Yes
what is hybrid inviability?
Genetic incompatibility of interbred species stops zygote development
Example sheep plus goat
what is hybrid sterility? and how does it happen
when different species can mate, but their (offspring) hybrid is sterile
Meiosis and hybrid fails
what is hybrid breakdown?
First generation hybrid is fertile but when hybrids mate, one hybrid is sterile
what can reproductive isolation lead to
Speciation
If significant evolutionary changes occur in either new or old population, what will it result in?
Formation of separate species
what is Sympatric speciation
when new species evolves in the same geographic area
Without physical barriers, like (water ,mountains)
what can Sympatric speciation be caused by?
Chromosome changes
Non-random mating that changes gene flow
what is alloPatric speciation?
when a population is divided idue to a physical barrier, such as a mountain, river, or desert.
These groups are geographically isolated from each other
