gene pools

population

group of organisms of same type living in same place at same time

gene pools

sets of genes within a population

allele

different versions of the same gene

allele frequency

percentage of organisms possessing particular gene within a gene pool. dynamic and changes over tim

variation in populations

differing selection pressures, mutations, random genetic drift, gene flow, and barriers to flow

selection pressures

factors that make certain phenotype advantageous over alternate phenotypes. can be natural or artificial

natural selection

when factors within a populations environment cause certain phenotypes to be advantageous for survival or reproduction

how natural selection is effects allele frequency

organisms with genes coding for advantageous phenotypes more likely to survive and reproduce, and thus more likely to pass on their genotype to their offspring

artificial selection

intentional reproduction of individuals in population that have desirable traits by humans. also called selective breeding

mutations

random changes in individual organisms genes or chromosomes. resulting new genotype creates a new phenotype

mutations effect on allele frequency

new phenotype can either be advantageous, neutral, or detrimental to the organisms survival and reproduction, thus affecting allele frequency

random genetic drift

changes in occurrence of genotypes in small populations due to luck, not selection. includes the founder effect

founder effect

when a new colony is started by a few members of the original population

founder effect on allele frequency

small population size means the colony may have reduced genetic variation from original population, or a non random sample of genes in original population

gene flow

gene pools can gain genes from or lose genes to other gene pools, such as populations in different locations

gene flow effect on allele frequency

gene flow increases changes in allele frequency

barriers

some gene pools get isolated from other gene pools, preventing gene flow

barrier effect on allele frequency

the barriers reduce gene flow therefore decreasing changes to allele frequency

types of barriers (2)

geographical, sociocultural

geographical barrier

physical barrier preventing gene flow between populations

sociocultural barrier

cultural or social barriers such as religion, social status, etc that affects which people will and wont reproduce with each other

immigration

population gaining new genes from external source. genes flow in

emigration

population loses genes to other gene pools. genes flow out