Speciation Exam 4 Flashcards
Acquire new alleles by
mutation and gene flow
Genetic drift has bigger impact on what population
small
Relative abundance of alleles altered by
genetic drift and natural selection
Stabilizing selection example
predators attacked too dark and too light mice not the inbetween
Directional selection does what
-acts against one phenotype
-environmental change
populations that potentially interbreed under natural conditions, produce fertile offspring
Species
Prezygotic barriers does what
block mating or fertilization
behavioral isolation is also the same as
mate recognition
*example- fireflies respond to pattern of their own species, not to others
mechanical isolation is
a physical incompatibility between reproductive organs of two organisms
gamete isolation is when
the egg and sperm are released but a zygote is not formed
temporal isolation is when
two or more species reproduce at different times
5 prezygotic barries are
habitat, temporal, mechanical, gametic, behavioral
Postzygotic barriers is when
mating occurs, zygote formed, but hybrid doesn’t survive or is not fertile
2 Postzygotic barriers are
non viable hybrid and infertile hybrid
speciation is
formation of new species
Adaptive radiation is
many diverse species may arise from common ancestors
Larger changes in a small populations gene pool due to random events is called
genetic drift
Natural selection usually for phenotypes that
favor survival
Directional selection example
all dark fur survives but light doesnt
Reproductive isolation ensures
evolutionary independence from other groups
example-frogs only mate with frogs who croak like themselves
habitat isolation is when
distinct habitats within same general area
*example- terrestrial, aquatic garter snakes don’t meet each other often
geographic isolation prevents
gene flow
requirements of separation are
-reproductive isolation of population
-genetic divergence
habitat differentiation reduces
gene flow and genetic divergence follows
