lecture 8

Biological Diversity (Biodiversity)

The variety of the Earth's species, the genes they contain, the ecosystems in which they live, and ecosystem processes such as energy flow and nutrient cycling.

Genetic Diversity

The genetic variation within all populations of a species.

Species Diversity

The number and abundance of species present in different communities.

Species Richness

The number of different species in a community.

Ecosystem Diversity

The variety of terrestrial and aquatic ecosystems on Earth and interactions among organisms in natural communities.

Functional Diversity

The biological/chemical processes and functional traits within species assemblages needed for survival.

Ecotone

A transitional zone where adjacent communities meet.

Edge Effect

The change in species composition that occurs at ecotones.

Latitudinal Gradient Pattern

Species richness generally declines along a gradient from the tropics (high diversity) to the poles (low diversity).

Species-Area Curve

A principle stating that species richness is directly related to a community's geographic size up to a limit.

Speciation

The process wherein natural selection leads to one species splitting into two or more distinct species.

Geographic Isolation

When different groups of the same population become physically isolated for long periods by barriers like mountains or rivers.

Reproductive Isolation

When mutation and natural selection operate independently in gene pools of geographically isolated populations, preventing interbreeding.

Biological Extinction

A process in which an entire species ceases to exist globally.

Local Extinction

When a population of a species becomes extinct over a large region, but not globally.

Endemic Species

Species found in only one specific area, making them especially susceptible to extinction.

Background Extinction

The continuous, low-level disappearance of species at a slow, normal rate.

Mass Extinction

The wiping out of large numbers of species during a relatively short period of geological time.

Endangered Species

A species in imminent danger of extinction throughout all or a significant portion of its range.

Threatened Species

Any species likely to become endangered within the foreseeable future.

Artificial Selection

Process where humans select desirable genetic traits in plants or animals and use selective breeding to propagate them.

Genetic Engineering

The alteration of an organism's genetic material by adding, deleting, or changing DNA segments to produce desirable traits.

Genetically Modified Organisms (GMO)

Organisms whose genetic material has been altered through biotechnology to express specific traits like delayed ripening or pest resistance.