APES: Chapter 4 vocab

adaptation

adaptation

Any genetically controlled structural, physiological, or behavioral characteristic that helps an organism survive and reproduce under a given set of environmental conditions. It usually results from a beneficial mutation. See biological evolution, differential reproduction, mutation, natural selection.

adaptive trait

see adaptation

alien species

see nonnative species

artificial selection

Process by which humans select one or more desirable genetic traits in the population of a plant or animal species and then use selective breeding to produce populations containing many individuals with the desired traits. Compare genetic engineering, natural selection.

background extinction rate

Normal extinction of various species as a result of changes in local environmental conditions. Compare mass extinction.

biodiversity

Variety of different species (species diversity), genetic variability among individuals within each species (genetic diversity), variety of ecosystems (ecological diversity), and functions such as energy flow and matter cycling needed for the survival of species and biological communities (functional diversity).

biological diversity

see biodiversity

biological evolution

Change in the genetic makeup of a population of a species in successive generations. If continued long enough, it can lead to the formation of a new species. Note that populations, not individuals, evolve. See also adaptation, differential reproduction, natural selection, theory of evolution

biome

Terrestrial regions inhabited by certain types of life, especially vegetation. Examples include various types of deserts, grasslands, and forests.

differential reproduction

Phenomenon in which individuals with adaptive genetic traits produce more living offspring than do individuals without such traits. See natural selection.

disturbance

An event that disrupts an ecosystem or community. Examples of natural disturbances include fires, hurricanes, tornadoes, droughts, and floods. Examples of human–caused disturbancesinclude deforestation, overgrazing, and plowing.

ecological diversity

The variety of forests, deserts, grasslands, oceans, streams, lakes, and other biological communities interacting with one another and with their nonliving environment. See biodiversity. Compare functional diversity, genetic diversity, species diversity.

ecological niche

Total way of life or role of a species in an ecosystem. It includes all physical, chemical, and biological conditions that a species needs to live and reproduce in an ecosystem. See fundamental niche, realized niche.

endemic species

species that is only found in one area. such species are especially vulnerable to extinction

evolution

see biological evolution

extinction

see biological extinction

fossils

Skeletons, bones, shells, body parts, leaves, seeds, or impressions of such items that provide recognizable evidence of organisms that lived long ago.

foundation species

Species that plays a major role in shaping a community by creating and enhancing a habitat that benefits other species. Compare indicator species, keystone species, native species, nonnative species.

functional diversity

Biological and chemical processes or functions such as energy flow and matter cycling needed for the survival of species and biological communities. See biodiversity, ecological diversity, genetic diversity, species diversity

gene mutation

see mutation

gene pool

sum total of all genes found in the individuals of the population of a particular species

gene splicing

see genetic engineering

generalist species

Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. Examples include flies, cockroaches, mice, rats, and humans. Compare specialist species.

genes

Coded units of information about specific traits that are passed from parents to offspring during reproduction. They consist of segments of DNA molecules found in chromosomes

genetic adaptation

Changes in the genetic makeup of organisms of a species that allow the species to reproduce and gain a competitive advantage under changed environmental conditions. See differential reproduction, evolution, mutation, natural selection

genetic diversity

Variability in the genetic makeup among individuals within a single species. See biodiversity. Compare ecological diversity, functional diversity, species diversity.

genetic engineering

Insertion of an alien gene into an organism to give it a beneficial genetic trait. Compare artificial selection, natural selection.

geographic isolation

separation of populations of a species into different areas for long periods of time

habitat

place or type of place where an organism or population of organisms lives. Compare ecological niche

indicator species

Species whose decline serves as early warnings that a community or ecosystem is being degraded. Compare foundation species, keystone species, native species, nonnative species.

invertebrates

animals that have no backbones. Compare vertebrates

keystone species

Species that play roles affecting many other organisms in an ecosystem. Compare foundation species, indicator species, native species, nonnative species.

mass extinction

Catastrophic, widespread, often global event in which major groups of species are wiped out over a short time compared with normal (background) extinctions. Compare background extinction.

mutation

Random change in DNA molecules making up genes that can alter anatomy, physiology, or behavior in offspring. See mutagen.

native species

Species that normally live and thrive in a particular ecosystem. Compare foundation species, indicator species, keystone species, nonnative species

natural rate of extinction

see background extinction

natural selection

Process by which a particular beneficial gene (or set of genes) is reproduced in succeeding generations more than other genes. The result of natural selection is a population that contains a greater proportion of organisms better adapted to certain environmental conditions. See adaptation, biological evolution, differential reproduction, mutation.

niche

see ecological niche

nonnative species

Species that migrate into an ecosystem or are deliberately or accidentally introduced into an ecosystem by humans. Compare native species

reproductive isolation

long-term geographic separation of members of a particular sexually reproducing species.

specialist species

Species with a narrow ecological niche. They may be able to live in only one type of habitat, tolerate only a narrow range of climatic and other environmental conditions, or use only one type or a few types of food. Compare generalist species.

speciation

Formation of two species from one species because of divergent natural selection in response to changes in environmental conditions; usually takes thousands of years. Compare extinction

species

Group of similar organisms, and for sexually reproducing organisms, they are a set of individuals that can mate and produce fertile offspring. Every organism is a member of a certain species.

species diversity

Number of different species (species richness) combined with the relative abundance of individuals within each of those species (species evenness) in a given area. See biodiversity, species evenness, species richness. Compare ecological diversity, genetic diversity

species equilibrium model

see theory of island biogeorgaphy

species evenness

Degree to which comparative numbers of individuals of each of the species present in a community are similar. See species diversity. Compare species richness.

species richness

Variety of species, measured by the number of different species contained in a community. See species diversity. Compare species evenness.

theory of evolution

Widely accepted scientific idea that all life forms developed from earlier life forms. It is the way most biologists explain how life has changed over the past 3.6–3.8 billion years and why it is so diverse today.

theory of island biogeography

Widely accepted scientific theory holding that the number of different species (species richness) found on an island is determined by the interactions of two factors: the rate at which new species immigrate to the island and the rate at which species become extinct, or cease to exist, on the island. See species richness.