Topic 3.2 IB ESS

Survival of the fittest

a shorthand way to say natural selection

On The Origin of Species

book by Charles Darwin laying out the theory of evolution by natural selection published in 1859

Holocene extinction event (6th mass extinction)

current extinction event in which the rate of mammal extinction is 45 times the usual rate of extinction; caused by human actions; started about 100,000 years ago and has accelerated in the last 100 years.

Speciation

gradual change in a species over a long time leading to formation of new species (cannot interbreed) because populations are isolated and subject to different environmental pressures

Natural selection

mechanism of evolution in which there is variation within a population, limited resources, competition for resources, some individuals better able to survive and reproduce, passing on heritable traits that increase survival of offspring

Continental drift

movement of the seven tectonic plates that make up the lithosphere slowly over time

Land bridges

narrow strips of land between continents or connecting islands to continents; land bridges can bring populations together or allow them to spread out.

Background extinction rate

one species per million species per year

Mass extinction

period of time in which the extinction rate dramatically increases; often caused by climatic change

Geographic isolation

populations are separated by a geographic barrier like an ocean, river, or mountain; this can lead to speciation if the two populations evolve differently

Theory of evolution

scientific theory stating that the heritable characteristics of biological populations changes over time

Plate tectonics

the study of the movement of the tectonic plates