Chapter 4: Biodiversity

APES Miller/Spoolman

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.

adaptive trait

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.

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.

background extinction rate

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

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.

biome

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

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.

endemic species

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

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.

extinction

Complete disappearance of a species from the earth. It happens when a species cannot adapt and successfully reproduce under new environmental conditions or when a species evolves into one or more new species.

fossils

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

gene mutation

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

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.

genetic diversity

Variability in the genetic makeup among individuals within a single species.

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.

invasive species

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

keystone species

Species that play roles affecting many other organisms in an ecosystem.

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.

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.

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.

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.

nonnative species

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

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.

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.

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.

species evenness

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

species richness

Variety of species, measured by the number of different species contained in a community.

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.

biodiversity

The diversity of life forms in an environment

differential reproduction

The idea that those best adapted to their environment will be most likely to survive and have offspring

foundation species

A species that has a strong role in structuring a community (can occupy any tropic level)