Evolution

species

two individuals that can interbreed to produce fertile offspring

natural selection

organisms which are better adapted to their environment are likely to survive and reproduce to produce offspring that are successful

genetic drift

variations in allele frequencies in population that occur by chance

founder effect

when a population is isolated and the founder members of the population are a small sample of the original population there may be a very different allele frequency

bottlenecking

after a disaster that reduces the population size the frequency of alleles may be different

continuous variation

shows a graduation from one extreme to the other

discontinuous variation

characteristics are clear cut and easy to tell apart

biochemical methods

compare specific molecules across different species to see how similar they are

morphology

organisms are organised according to their structure, outward appearance and internal structure

homologous structures

body parts that are structurally similar even if used for different functions

analogous structures

separate evolution of structures with similar functions but different origin

divergent evolution

a species with a common ancestor develop differently to become increasingly distinct

convergent evolution

a species without a common ancestor that have similar characteristics due to similar environmental pressure

classification

the organisation of living organisms into groups according to their shared similarities

taxonomy

the study of principles behind classification

phylogenetic

organisms are grouped to reflect evolutionary relatedness

hierarchy

where a large group of items is split into smaller and smaller groups

heritable variation

results from genetic changes in sexual reproduction

non heritable reproduction

environmental influences that determine phenotype variation

gene pool

all alleles of all genes of all individuals in a population at any one time

allele frequency

a measure of the relative frequency of an allele on a genetic locus in a population