Evolution terms

Adaptation

Adaptation

Process that helps an organism survive and reproduce in a particular environment

Structural adaptation

Adaptation that changes the structures in an organism (opposable thumb)

Behavioural adaptation

Change in behaviour that helps organism survive (hibernation)

Physiological adaption

Change in the organisms ability to regulate and maintain homeostasis (venom)

Mimicry

Many harmless organisms ressemble harmful organisms in colouration or structure... avoid predators (Massasauga Rattler - venomous; Fox snake - non venomous)

Natural selection

The process of populations changing in favour of those who have advantangeous traits due to environmental pressures.

• Occurs only in populations with variation

Fitness

Measured by the # of fertile offspring produced in the next generation

Artificial selection

Describes changes to a population caused by deliberate, selective breeding by humans

Microevolution

Change in allele frequencies in a population over generations

Point mutation

Change in one base in a gene

• Mutations in noncoding regions of DNA are often harmless

• Mutations might not affect protein production because of redundancy in genome

• Mutations that change protein production are often harmful

  • Can sometimes increase the fit between organism and environment

Population

Localized group of individuals capable of interbreeding and producing fertile offspring

Gene pool

Consists of all the alleles for loci in a population

Mutation

Change that occurs in DNA of individual, a heritable mutation (in gamete) mutation has the potential to affect an entire gene pool

Gene flow

Is the transfer of alleles from one population to another, migrations into or out of a population can change allele frequencies.

Non-random mating

Occurs when individuals select mates based on their phenotypes; interbreeding increases proportion of homozygous dominant and resessive individuals/decrease heterozygous

Genetic Drift

Refers to changes in the allele frequencies of a gene pool due to c hance events

Founder effect

Occurs when a few individuals found a colony. Only a small fraction of the total genetic diversity of the original population is represented.

Bottleneck effect

Loss of genetic diversity due to extreme reduction in size of a population (extinction). Prevents majority of genotypes from participating in the production of the next generation; alleles of survivors dictated by chance

• Rare alleles are likely to be eliminated

Natural selection

Result of environment selecting for individuals in a population with certain traits that make them better suited to survive and reproduce than others

Stabilizing selection

Average phenotype within a population is favoured by the environment.

Directional selection

favours individuals with a more extreme variation of a trait causing a shift away from average conditions.

Disruptive selection

Favours individuals with variations at opposite extremes.

Vestigial features

structures that once performed an important function in ancestral species that now have no use (i.e. tailbone, appendix, wisdom teeth, pig’s hind toe etc.)

Biogeography

Remote islands are populated by species that evolved from species that had travelled from closest major land mass

Homologous structures

share similar physical features, but may not serve the same purpose. indicates CLOSE ANCESTRY.

Analogous structures

may share a common function, but do not have similar anatomy, therefore DO NOT INDICATE CLOSE ANCESTRY.

Competition within populations

All species have more offspring than can survive to reproduce

Species

a group of similar organisms which can interbreed and produce fertile offsprings

Sexual selection

Any trait that aids in an organisms ability to attract mates and breed