speciation Flashcards
lecture 11 - Mark Briffa
binomial classification
domain kingdom phylum (subphylum) class order family genus species
biological species concept
groups of interbreeding natural populations thatare reprodcutively isolated from other such groups
gene pool
the number of different genes in an interbreeding population.
the gene pool/species is the unit of evolution
(individuals are the unit of selection)
allopatric speciation
new species form geographically apart from its ancestor
away from
cline
gradient of continous genotypic or phenotypic variation within a species
ring species
a circular arrangement of populations with one boundary characterized by reproductive isolation, but intergradation among populations elsewhere.
physical barriers
- a new physical barrier could divide the geographic range
- would prevent gene-flow between isolated populations
- different selection oressures, different random mutation , genetic drift
- full reproductive isolation
( allopactric speciation)
reinforcement
a process of speciation where natural selection increases the reproductive isolation between two populations of species
reinforcement = assortative mating
assortative mating
mating pattern and a form of sexual selection in which individuals with similar phenotypes or genotypes mate with one another more frequently than would be expected under a random mating pattern
peripatric speciation
- a small population at the edge of the species range is isolated
- extreme conditions
- rapid evolutionary
parapatric speciation
new species formsm withinn a contigous population
new niche or range with different contditions and selection pressure but no physical barriers
next to
founder effect
the reduced genetic diversity which results when a small group of individuals become seperated from larger population
hybrid zone
regions where genetically distinct populations meet, mate, and produce at least some offspring of mixed ancestry
sympatric speciation
new specied forms in geographical range on ancestor
together