BIO 2 MECHANISM OF SPECIATION Flashcards
a process by which two species that could otherwise produce hybrid offspring are prevented from doing so.
ISOLATION
-Are mechanisms that prevent closely related species from interbreeding.
-Stops two species from producing viable, fertile offspring.
Reproductive Barriers
Also known as pre - reproductive barrier
prevent mating between two closely related species.
Prezygotic Barrier
Also known as pre - reproductive barrier
prevent mating between two closely related species.
Prezygotic Barrier
Physical barrier separate ancestral species.
New species appear in different areas.
Geographic Isolation
Species occur in same region, but occupy different habitats so they rarely encounter each other
Ecological isolation
Two closely related species reproduce at different times of the day, season, or year.
Temporal “time” isolation
Unique behavioral patterns & rituals isolate species.
-identifies members of species.
-attract mates of same species.
Behavioral isolation/ Ethological isolation
Morphological differences can prevent successful mating
differences in their reproductive organs prevent interbreeding
Mechanical isolation
-A mechanism of reproductive isolation which inhibits mating between two distinct species, by ensuring that their gametes don’t interact with each other.
-Sperm of one species may not be able to fertilize eggs of another species
Gametic isolation
Sperm cannot penetrate egg because of receptor recognition malfunction or lock & key between egg & sperm is disrupted.
Biochemical barrier
Sperm cannot survive in female reproductive tract.
Chemical Incompatibility
Prevent hybrid offspring from developing into a viable, fertile adult.
Postzygotic barriers
Chromosomes of parents differ in number or structure thus meiosis in hybrids will fail to produce a normal gametes
Hybrid sterility
Genes of different parents can impair or stop the development of the hybrid.
Hybrid viability
First generation of hybrids are fertile and viable
Succeeding generations are sterile.
Hybrid Breakdown
-Geographical barrier
-Separate two large populations.
Allopatric
Geographical barrier
Separate a small number of species from the whole population.
Peripatric
No geographical barrier
Leave in the same habitat
the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region.
Sympatric
No geographical barrier
Leave within the same habitat.
Slight difference in the habitat, new niche.
a species is spread out over a large geographic area
Parapatric
the inability of a species to breed successfully with related species due to geographical, behavioral, physiological, or genetic barriers or differences. then what is this
prezygotic isolation
speciation that occurs when two groups of the same species live in the same geographic location, but they evolve differently until they can no longer interbreed and are considered different species.
sympatric speciation
is a form of reproductive isolation, wherein habitat preferences of species lowers the probability of mating.
ecological isolation
a process by which two species that could otherwise produce hybrid offspring are prevented from doing so.
reproductive isolation
