Topic 10.3: Gene pools and speciation Flashcards
Definition of gene pool
All the genes and their different alleles, present in an interbreeding population
Definition of allele frequency
The proportion of a particular allele within a population
Is it possible to have multiple gene pools for the same species?
Yes, some populations of the same species are reproductively isolated.
Relationship between evolution and allele frequency
Evolution requires the allele frequencies change with time in populations
How do allele frequencies change with time in populations? (5)
a) Mutation
b) Gene flow
c) Sexual reproduction
d) Random events
e) Natural selection
When does reproductive isolation occurs?
When barriers prevent two populations from interbreeding, keeping their gene pools separate.
Ways in which reproductive isolation occurs in populations
a) Geographic (allopatric)
b) Behavioral (sympatric)
c) Temporal (sympatric)
When does geographic isolation occurs?
When two populations occupy different habitats or separate niches
How does behavioral isolation occur?
Two populations exhibit different specific courtship patterns
How does temporal isolation occur?
Two populations differ in their periods of activity or reproductive cycles
Definition of speciation
Formation of a new species by the splitting of an existing population
Paces at which speciation occur
a) Gradualism
b) Punctuated equilibrium
Gradualism
Evolution occurs at a constant pace over a long period of time (due to the accumulation of mutations).
Punctuated equilibrium
Long periods of relative stability in a species are “punctuated” by periods of rapid evolution
Definition of polyploid organism
One that has more than two sets of homologous chromosomes
