APES Chapter 4

natural selection

Process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest

biological evolution

change in a populations genetic makeup through successive generations by means of natural selection

mutation

a change in DNA, some harmless, some harmful, some beneficial

adaptation

a heritable trait that gives an organism an advantage to survive and reproduce in its environment

coevolution

the process in which two different species, that interact over a long period of time, cause changes in the gene pool of the other

hybridization

two different species crossbreed and produce offspring that in some cases has a better ability to survive

gene pool

All the genes, including all the different alleles for each gene, that are present in a population at any one time

niche

an organism's role or way of life within a community or ecosystem

fundamental niche

the full potential range of physical, chemical, and biological conditions and resources it COULD use if there was no competition from other species

realized niche

the actual range of physical, chemical, and biological conditions and resources due to competition with other species

generalist species

species that have a broad niche; can live in many different areas, eat a variety of foods, and tolerate a wide range of environmental conditions

specialist species

species that occupy a narrow niche; live in only one type of habitat, use limited types of food, tolerate a narrow range of climatic and other environmental conditions

speciation

two species arise from one; for sexual reproducing organisms this occurs when members of a population can no longer breed and produce fertile offspring

geographic isolation

different groups of the same species become physically separated (mountains, rivers etc) for long periods of time; may lead to reproductive isolation and speciation.

reproductive isolation

mutation and natural selection operate independently in the gene pool of geographically isolated species; over long periods of time the separated populations may become so different that they can no longer produce fertile offspring

extinction

an entire species ceases to exist

endemic species

species found in only one area; typically islands and other unique areas; vulnerable especially in tropical rainforests

mass extinction

catastrophic, widespread events that cause the extinction of a significant number of species; there is evidence of five; many scientists believe we are currently in the sixth.

biodiversity

The amount of biological or living diversity per unit area. It includes the concepts of species diversity, ecosystem diversity and genetic diversity.

artificial selection

changing the genetic characteristics of a population through selective breeding

genetic engineering

altering an organism's genetic material by adding, deleting, or changing segments of its DNA

recombinant DNA

altering DNA to contain genes or portions of genes from organisms of different species

human adaptive traits

the traits that have allowed humans to thrive as a species: precision grips with strong opposable thumbs, ability to walk upright, and complex brains

chemical evolution

inorganic compounds in earth's early atmosphere reacted to produce amino acids, simple sugars, and other organic molecules

ecosystem

A community of organisms and their abiotic environment.

habitat

Physical area in which an organism lives

range

the area in which a particular species is found; includes areas populations may migrate to or hibernate in.

species

A group of similar organisms that can breed and produce fertile offspring.