species

species

population of organisms that successfully interbreed with each other, (or could possibly breed, under natural conditions) and are reproductively isolated from other such groups

reproductive isolation

keeping species separate, the set of biological barriers that prevent members of two different species from breeding and producing fertile offspring

Prezygotic barriers, reproductive isolation

individuals are physically unable to mate with each other (cell doesn’t line up, reproductive parts don’t match) → male’s reproductive cell is unable to fertilize the female’s reproductive cell, before fertilization, ex: dogs and pigs

Postzygotic barriers, reproductive isolation

matings produce hybrid individuals that do not survive long after fertilization (chromosome differnces causes their to be no cell division) if survive, mule they are infertile. after fertilization

Linnaean classification system

D K P C O F G S

two main types of speciation (making new species:)

Allopatry, sympatry

Allopatric Speciation

different locations, species can evolve, a geographic barrier causes one group of individuals in a population to be reproductively isolated from another group

Sympatric Speciation

same locations, choosing different foods randomly, genetic change happen from mutation, where new species evolve due to reproductive isolation mechanisms like polyploidy or specialized feeding behaviors

Microevolution

Changes in allele frequencies (genetic composition) within a single population or species. ex: A shift in coloration from light to dark during the industrial revolution in England.

Macroevolution

Major evolutionary changes that occur above the species level, leading to the creation of new taxonomic groups. ex: Land mammals transitioning to fully aquatic environments, losing hind limbs and evolving flippers.

Adaptive radiation

when a small number of species diversify into a large number of species.

Mass Extinction

metor, competition suddenly eliminated, remaining species rapidly diversify

background extinction

colonizers can rapidly diversify, evolution of an innovative feature that increases fitness