APES Unit 2: The Living World: Biodiversity

Species Richness

The number of species in a given area

Species Eveness

The relative proportion of individuals within the different species in a given region

Evolution

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

Gene

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

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.

Evolution by natural selection

The process in which the environment determines which individuals survive and reproduce.

Fitness

An individual's ablility to survive and reproduce

Adaptation

A trait that improves an individual's fitness

Gene flow

The process by which individuals move from one population to another and thereby alter the genetic composition of both populations.

Extinction

The death of the last member of a species

Range of tolerance

The limits to the abiotic conditions that a species can tolerate

Fundamental niche

The suite of abiotic conditions under which a species can survive, grow, and reproduce

Realized niche

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

endemic species

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

ecological succession

series of gradual changes that occur in a community following a disturbance

primary succession

An ecological succession that begins in an area where no biotic community previously existed

secondary succession

reestablishment of a damaged ecosystem in an area where the soil was left intact

pioneer species

First species to populate an area during primary succession

climax community

A stable, mature community that undergoes little or no change in species over time

cultural services

the spiritual and recreational benefits that ecosystems provide

regulating services

the ways that ecosystems control important conditions and processes, such as climate, the flow of water, and the absorption of pollutants

supporting services

basic ecosystem processes (nutrient cycles, soil formation)

provisioning services

products obtained from ecosystems

keystone species

A species that influences the survival of many other species in an ecosystem

indicator species

Species that serve as early warnings that a community or ecosystem is being degraded.

island biogeography theory

explains how species come to be distributed among oceanic islands

bottleneck effect

A change in allele frequency following a dramatic reduction in the size of a population

founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

selective pressure

environmental conditions that select for certain characteristics of individuals and select against other characteristics

zone of intolerance

A region that is so far removed from an organism's optimal range for an environmental variable that the organism cannot survive.

Examples of primary succession

Glacier retreat, lava flow, recently exposed sand dune; topsoil is not present

Examples of Secondary Succession

Hurricane

Flooding

Forest fire

Clear-cut forest

Avalanche

Landslide

examples of keystone species

sea stars, sea otters, beavers

examples of indicator species

lichens, Northern spotted owls, amphibians

examples of supporting services

nutrient cycling, soil formation, primary productivity

examples of provisioning services

Food, fuel, raw materials, freshwater & medicines.

Examples of regulating services

Air quality, climate, erosion control, pollination & natural disaster mitigation.

Examples of cultural services

Recreation and mental and physical health

Tourism

Aesthetic appreciation and inspiration for culture, art, and design

Spiritual experience and sense of place

Biodiversity

the variety of life in the world or in a particular habitat or ecosystem.

species diversity

The number and relative abundance of species in a biological community.

genetic diversity

The range of genetic material present in a gene pool or population of a species.

ecosystem diversity

variety of habitats, living communities, and ecological processes in the living world

zone of physiological stress

range where organisms survive, but experience some stress such as infertility, lack of growth, decreased activity, etc.

optimal range of tolerance

range where organisms survive, grow, and reproduce