Genetic Change and Selection Pressures Flashcards
Selective Pressures
factors in the environment that select for or against a certain phenotype or mutation
Natural Selection
indivuals with particular phenotypes or mutations are better suited to the environment so are successful and reproduce, passing on favourable alleles
Speciation
the development of new species. Formation of new species due to evolution, without mutations, there would be no new alleles, so no evolution to new species
Species
a group of organisms that can produce fertile offspring without human interaction
Population
a group of the same species in the same place at the same time
Gene Pool
all the alleles present in an interbreeding population
Germ cells
those cells that can potentially contribute their genes to future generations. Gametes and cells that give rise to them
Soma Cells
the body consisting of cells that do not contribute to the gametes and die with the rest of the body
Allele Frequency
the proportion of an allele in a gene pool compared with that of another allele
Directional Selection
selection against one end of the range of variation, resulting in a progressive change of allele frequency
Stabilising Selection
Selection acting against the extremes of a range of variation
Sexual Selection
Selection for the ability of an organism to obtain a mate
Genetic Bottleneck
Loss in genetic diversity resulting from an extreme reduction in population numbers
Founder Effect
Change in allele frequency due to chance when a small group splits from parent population
Disruptive selection
selecting the extremes of a range of variation
