Unit 2.1-2.4 - The Living World Biodiversity

biodiversity

The diversity of life forms in an environment.

genetic diversity

A measure of the genetic variation among individuals in a population.

species diversity

The number of species in a region or in a particular type of ecosystem.

ecosystem/habitat diversity

The variety of ecosystems within a region.

bottleneck effect

A reduction in the genetic diversity of a population caused by a reduction in its size (usually due to a catastrophe, such as a fire or hurricane).

species

A group of organisms that is distinct from other groups in its morphology (body form and structure), behavior, or biochemical properties. It is a group of individuals that are able to interbreed and produce fertile offspring.

speciation

The evolution of new species.

background extinction rate

The average rate at which species become extinct over the long term – about 2 species per year worldwide.

species richness

The number of species in a given area – a measure of species diversity.

factors that influence species richness

Latitude (highest towards the equator/where there is more sun available), Time (the longer a habitat exists, the more colonization, speciation and extinction can occur), Habitat size (can support more species), and Distance from other communities (may have fewer species due to distance).

species evenness

The relative proportion of individuals within the different species within a given area. An ecosystem has high species evenness if its species are all represented by similar number of individuals.

habitat

The place where an organism lives (its address) – the place where an organism finds food, shelter, protection, etc..

specialist species (with examples)

Species with a narrow ecological niche. They may be able to live in only one habitat and can only tolerate a narrow range of conditions. Examples include Koalas and pandas.

generalist species (with examples)

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

simpsons diversity index (what it is)

A calculation that is a measure of diversity that takes into account both richness and evenness. Values near 1 indicate a highly diverse ecosystem, and values near 0 indicate a less diverse ecosystem.

shannon wiener index of diversity (what it is)

A calculation that is a measure of diversity that takes into account both richness and evenness. Values near 7 indicate a highly diverse ecosystem, and values near 0 indicate a less diverse ecosystem.

ecosystem services

The processes by which life-supporting resources such as clean water, timber, fisheries, and agricultural crops are produced.

provisioning services (with examples)

Services provided by the ecosystem that produce goods that humans can use directly. Examples include Food, Raw materials (wood, biofuels, fibers), Fresh water (regulating flow, storage, and purification), and Medicinal resources (plants and mushrooms for medicine and pharmaceuticals).

regulating services (with examples)

Services provided by the ecosystem that help to regulate and maintain environmental conditions. Examples include Local climate and air quality maintenance, Carbon sequestration and storage, Moderation of extreme events (like floods/storms), Waste-water treatment, Erosion prevention and maintenance of soil fertility, Pollination, and Biological control.

cultural services (with examples)

The non-material benefits people obtain from ecosystems. Examples include Recreation and mental and physical health, Tourism, Aesthetic appreciation and inspiration for culture/art/design, and Spiritual experience and sense of place.

supporting services (with examples)

Services that provide living spaces for plants or animals and maintain a diversity of plants and animals, serving as the basis of all other ecosystem services. These include Habitats for species, and Maintenance of genetic diversity.

island biogeography (including distance, evolution, and biogeography)

A theory that demonstrates the dual importance of habitat size and distance in determining species richness. Distance from the mainland influences species richness because fewer species can disperse longer distances. Evolution is also affected, as some species have evolved to be specialists due to limited resources on an island. The theory may also refer to protected habitats (like national parks) surrounded by less hospitable areas (a form of biogeography).

ecological tolerance

The limits to the abiotic conditions that a species can tolerate before injury or death results (also called range of tolerance). Every species has an optimal environment in which it performs well.

tolerance curve

Illustrates the range of survival for a species or population.

fundamental niche

The set 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