Midterm 11 Flashcards
the biological species concept
separate species are reproductively isolated from one another
reproductive barriers
- pre mating, pre zygotic
- post mating, pre zygotic
- post zygotic
- pre mating, pre zygotic
habitat isolation
temporal isolation
behavioral isolation
mechanical isolation
- post mating, pre zygotic
gametic isolation
- post zygotic
hybrid inviability
hybrid sterility
hybrid breakdown
allopatric speciation
different country
passively by vi-cariance events i.e., new rivers, deserts
actively by dispersal events
sympatric speciation
same country
constant gene flow makes sympatric speciation difficult and unlikely
the Dobzhansky-Muller Model DMI
negative epistatic interactions that occur between different alleles of different genes with a different evolutionary history
the neutral theory of molecular evolution
most variation at the molecular level does not affect fitness
rate of neutral molecular evolution = neutral mutation rate x probability of fixation of a neutral mutation
in a diploid ppl, new mutations start at frequency
1/2N
the probability that a new neutral mutation in a diploid ppl reaches 100% if there
1/2N
the population experiences __ mutations per generation
2N x mu
rate of neutral molecular evolution =
mu
2Nmu x 1/2N
neutral mutation rate x probability of fixation of a neutral mutation
implications of the neutral theory
- if the mutation rate is constant, neutral evolution should happen at a constant rate
- if beneficial mutations are very rare, the rate of evolution is a function of the mutations that are neutral f0
- rate of neutral molecular evolution = f0 x mu
mu
each copy of the locus get mutated with mutation rate mu per generation
