Speciation
Species An organism that can mate with another and produce fertile offspring
Speciation Isolating Mechanisms Different gene pools 2 species cannot interbreed to produce fertile offspring Reproductively Isolated
Behavioral Isolation Differences in courtship rituals or other types of behavior Songs of birds
Geographic Isolation 2 populations separated by geographic barriers (rivers, mountains, bodies of water) Abert Squirrel vs. Kaibab Squirrel
Temporal Isolation Species reproduce at different times
Speciation Northern Arctic Fox Spreads northward and Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Adapted to cold through heavier fur, short ears, short legs, short nose. White fur matches snow for camouflage. Gray Fox Arctic Fox Different environmental conditions lead to different selective pressures and evolution into two different species. Spreads northward and southward separates Southern population Northern Early fox
Speciation Two species arise from one Allopatric Sympatric Requires Reproductive isolation Geographic: Physically separated Temporal: Mate at different times Behavioral: Bird calls / mating rituals Anatomical: Picture a mouse and an elephant hooking up Genetic Inviability: Mules Allopatric Speciation that occurs when 2 or more populations of a species are geographically isolated from one another The allele frequencies in these populations change Members become so different that that can no no longer interbreed Sympatric Populations evolve with overlapping ranges Behavioral barrier or hybridization or polyploidy
COEVOLUTION: Interaction Biodiversity Species so tightly connected, that the evolutionary history of one affects the other and vice versa.
Adaptive Radiation Single species or small group of species evolves into several different forms Darwin’s Finches Reptiles & Dinosaurs
How Long does Evolution take? Gradualism Slow changes over time Punctuated Equilibrium Long, stable periods followed by short periods of quick changes
Gradualism