Microevolution

Genetic DriftThe process of chane in the genetic composition of population due to chance or random events rather than by natural selection resulting in changes in allele frequencies over time

Bottleneck EffectGenetic drift resulting from the reduction of a population, normally by a natural disaster.

Gene PoolThe total number of genes of every individual in an interbreeding population

Gene FlowThe flow of individuals in and out of a populatoin introduces new alleles and increases genetic variation within that population.

Behavioral IsolationOccurs when two populations ae capable of interbreeding but have differences in courtship rituals or other reproductive strategies that involve behavior. ex: eastern and western meadowlarks are similar birds but they have different songs to attract mates.

Temporal IsolationA reproductive isolating mechanism in which members of different species mate at different times of the year in different seasons.

Non-random matingIf species continued to pursue in non random mating, the allele frequencies will not change and the population will not evolve. Hady-Weinberg pronciple states this to be true.

HybridizationThe act or process of mating organisms of different varieties or species to create a hybrid.

Allopatric SpeciationA speciation in which biological populations are physically isolated by an extrinsic barrier and evolve intrinsic (genetic) reproductive isolation, such that if the barrier breaks down, individuals of the population can no longer interbreed.

Sympatric SpeciationA speciation in which new species evolve from a single ancestral species while inhabiting the same geographic region.

Natural SelectionNatural selection effects he change in gene frequency in a population because only the selected traits are most helpful for species and their offspring in order to survive.

Geographic IsolationTwo populations are separated by geographic barriers such as rivers, mountains, or bodies of water.

MICROEVOLUTION

Genetic DriftThe allele becomes more or less common simply by chance. As time changes, a series od chance occurrences of this tpe can cause an allele to become common in a population, changing the gene frequency.

MutationWhen a mutation occurs there is an unexpected change in the gene frequency. The mutation can produce many changes in the phenotype causing the effect on the organisms fitness or ability to survive and reproduce in its environment.