The origin of species Flashcards
What are the 3 modes of selection
Directional - favors idivs at one end of phenotypic range
Stabilizing - favors indivs int he middle of range
DIsruptive - favors indivs at either end of range
Ex of directional selection
finch beaks in drought
elephant tusks
ex of disruptive selection
black bellied seed cracker finches
ones with small beak are better at small seeds
ones with big beak better at big seeds
not much in between
ex of stabilizing selection
human baby birth weight
What is adaptive radiation
a single animal adapts to fill available niches in the environment
What is microevolution
consists of adaptations that evolve within a population, confined to one gene pool
What is macroevolution
refers to evolutionary change that happens above species level
What is the biological species concept
states that a species is a group of population that can breed together and produces fertile, healthy kids
What is reproductive isolation
barriers that stop 2 species from producing viable offspring
What are prezygotic barriers
habitat - diff location
, temporal - diff time of mating
-, behavioral - diff mating rituals
, mechanical - diff ways of reproducing
, gematic - sperm cannot fertilize egg
What are post zygotic barriers
reduced hybrid viability - hybrid does not dev well,
reduced hybrid fertility - hybrid cannot reproduce ,
hybrid breakdown, - hybrid can produce offspring but they are stunted and unhealthy
types of speciation
Allopatric
SympatricW
What is allopatric speciation
a population is geographically isolated or seperated from another
what is sympatric speciation
a mutation happens and makes it impossible for the daughter generation to mate with the parent gen
can be caused by polyploidy
Limits of biological species concept
it does not apply to things that produce asexually or fossils.
