levels of biodiversity
ecosystem diversity, species diversity, and genetic diversity
The variety of ecosystems within a given region.
The variety of species within a given ecosystem.
The variety of genes within a given species.
The number of species in a given area.
The relative proportion of different species in a given area.
The branching patterns of evolutionary relationships. They are based on the similarity of traits among species.
A change in the genetic composition of a population over time.
Evolution occurring below the species level.
Evolution that gives rise to new species, genera, families, classes, or phyla.
A physical location on the chromosomes within each cell of an organism.
The complete set of genes in an individual.
A random change in the genetic code produced by a mistake in the copying process.
The genetic process by which one chromosome breaks off and attaches to another chromosome during reproductive cell division.
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.
An individual's ability to survive and reproduce.
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.
A change in the genetic composition of a population over time as a result of random mating.
A reduction in the genetic diversity of a population caused by a reduction in its size.
A change in a population descended from a small number of colonizing individuals.
Physical separation of a group of individuals from others of the same species.
The result of two populations within a species evolving separately so they can no longer interbreed and produce viable offspring.
The process of speciation that occurs with geographic isolation.
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.
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.
The suite of ideal environmental conditions for a species.
The range of abiotic and biotic conditions under which a species actually lives.
Areas of the world in which a species live.
A species that can live under a wide range of abiotic or biotic conditions.
A species that is specialized to live in a specific habitat or to feed on a small group of species.
The remains of an organism that has been preserved in rock.
A large extinction of species in a relatively short period of time.