Evolution and Natural Selection

natural selection

process of evolution developed by Darwin, based on four ideas: overproduction, variation, competition & environmental changes. It explains how traits of a population can change over time.

evolution

Changes in a species' population over time.

homologous structure

similar structures inherited from a common ancestor (ex. birds wings, reptile limbs); however these structures have different functions.

vestigial structure

reduced or non-working structure that indicates shared common ancestry (ex. human appendix)

embryo

organism's early prebirth stages of development

fossil records

Provides record of species, shows similar characteristics between living and extinct

adaptation

Trait shaped by natural selection that increases an organisms reproductive success

geographic isolation

isolation between populations due to physical barriers

artificial selection

selection by humans through directed breeding (Breeding of useful traits from the natural variation) to produce offspring with desired traits.

survival of the fittest

process by which individuals that are BETTER suited to their environment survive and reproduce most successfully; often used interchangeably with the term 'natural selection'.

genetic variation

The variety of different types of genes in a species or population.

competition

the struggle between organisms to survive in a habitat with limited resources

environmental changes

change in environment that can affect an organism's ability to survive

overproduction

organisms produce more offspring than can survive

mutation

a random error in gene replication that leads to a change

extinction

A term that typically describes a species that no longer has any known living individuals.

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection

phylogenetic tree

branching diagram showing evolutionary relationships of organisms with a common ancestor

radioactive dating

A technique used to determine the actual age of a fossil on the basis of the amount of a radioactive element it contains