APES chapter 5

levels of biodiversity

ecosystem diversity, species diversity, and genetic diversity

ecosystem diversity

The variety of ecosystems within a given region.

species diversity

The variety of species within a given ecosystem.

genetic diversity

The variety of genes within a given species.

species richness

The number of species in a given area.

species evenness

The relative proportion of different species in a given area.

phylogenies

The branching patterns of evolutionary relationships. They are based on the similarity of traits among species.

evolution

A change in the genetic composition of a population over time.

microevolution

Evolution occurring below the species level.

macroevolution

Evolution that gives rise to new species, genera, families, classes, or phyla.

gene

A physical location on the chromosomes within each cell of an organism.

genotype

The complete set of genes in an individual.

mutation

A random change in the genetic code produced by a mistake in the copying process.

recombination

The genetic process by which one chromosome breaks off and attaches to another chromosome during reproductive cell division.

phenotype

A set of traits expressed by an individual.

evolution by artificial selection

A change in the genetic composition of a population over time as a result of humans selecting which individuals breed, typically with a preconceived set of traits in mind.

evolution by natural selection

A change in the genetic composition of a population over time as a result of the environment determining which individuals are most likely to survive and reproduce.

Darwin's theory of evolution by natural selection

Individuals produce an excess of offspring. Not all offspring can survive. Individuals differ in their traits. Differences in traits can be passed on from parents to offspring. Differences in traits are associated with differences in the ability to survive and reproduce.

fitness

An individual's ability to survive and reproduce.

adaptation

A trait that improves an individual's fitness.

evolution by random processes

The genetic composition of a population changes over time, but the changes are not related to differences in fitness among individuals. They include mutations, genetic drift, bottleneck effects, and founder effects.

genetic drift

A change in the genetic composition of a population over time as a result of random mating.

bottleneck effect

A reduction in the genetic diversity of a population caused by a reduction in its size.

founder effect

A change in a population descended from a small number of colonizing individuals.

geographic isolation

Physical separation of a group of individuals from others of the same species.

reproductive isolation

The result of two populations within a species evolving separately so they can no longer interbreed and produce viable offspring.

allopatric speciation

The process of speciation that occurs with geographic isolation.

sympatric speciation

The evolution of one species into two, without geographic isolation.

pace of evolution

A species can better adapt to an environmental change if the rate of the environmental change is relatively slow, the population has high genetic variation for selection to act on, the population is relatively small, and the generation time is short.

genetic engineering

Techniques that scientists use where they can copy genes from a species with some desirable trait, such as rapid growth or disease resistance.

genetically modified organism

(GMO) An organism produced by copying genes from a species with a desirable trait and inserting them into another species.

range of tolerance

The limits to the abiotic conditions that a species can tolerate.

fundamental niche

The suite of ideal environmental conditions for a species.

realized niche

The range of abiotic and biotic conditions under which a species actually lives.

distribution

Areas of the world in which a species live.

niche generalist

A species that can live under a wide range of abiotic or biotic conditions.

niche specialist

A species that is specialized to live in a specific habitat or to feed on a small group of species.

fossil

The remains of an organism that has been preserved in rock.

mass extinction

A large extinction of species in a relatively short period of time.