Unit 2 - 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

The “products” obtained from ecosystems.

• Food

• Fibers

• Ornamentals
  Medicines

• Biofuels

• Fresh water

• Genetic resources

regulating services

Benefits obtained from the regulation of ecosystem

• Climate regulation

• Flood prevention

• Erosion control

• Pest control

• Pollination

• Seed dispersal

• Disease regulation

cultural services

Nonmaterial benefits obtained from ecosystems

• Educational

• Recreational

• Sense of place

• Spiritual

• Cognitive development

• Stress relief

• Gardening

• Tourism

supporting services

services necessary for the production of all other ecosystem services

• Biodiversity

• Nutrient recycling

• Primary productivity

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

survive, grow, and reproduce → survive and grow → survive

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

anthropogenic activities

(chiefly of pollution or environmental change) originating in human activity

• Deforestation

• Overpopulation

• Pollution

K-T extinctions

more than ¾ of all plant and animal species became extinct

local extinctions

local natural species go extinct in their original habitats

background extinctions

the loss of species at a low rate of extinction (1 to 5 species for each million species on Earth)

mass extinctions

a significant rise in extinction rate (25%-75%)

usually due to some catastrophic event

episodic

groups of events that happen occasionally

• El Nino

• Hurricane Season

• Pollen Release

microevolution

evolution below the species level

small genetic changes

macroevolution

evolution that gives rise to new species

genera, families, classes, or phyla

large scale, long term evolutionary changes

artificial selection

the process in which humans determine which individuals breed

• dog breeding

herbicide resistance

the process by which farmers' repeated use of the same herbicide creates a selective pressure on weed populations, causing them to evolve resistance over time

natural selection

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

survival of the fittest & adaptation

mutations

a random change in the genetic code produced by a mistake in the copying process

as the number of mutations accumulates, evolution occurs

gene flow

the process by which individuals move from one population to another and thereby alter the genetic composition

genetic drift

a change in the genetic composition of a population over time as a result of random mating

founder effect

a change in the genetic composition of a population as a result of descending from a small number of colonizing individuals

speciation

the evolution of a new species

new species evolve through two processes

allopatric speciation

the process of speciation that occurs with geographic isolation

sympatric speciation

the evolution of one species into two, without geographic isolation

ecological succession

the predictable replacement of one group of species by another group of species over time

primary vs secondary succession

primary occurs on surfaces initially devoid of soil

secondary succession occurs in areas that have been disturbed but not lost their soil

primary succession

pioneer species → help create soil → mid successional species → grow and help form more soil → late successional plant (mostly trees) → climax community

pioneer species

a species that can colonize new areas rapidly and grow well in full sunshine

they break down the rock chemically and physically

these processes along with the organic matter of dying pioneer species create soil

keystone species

a species that is not very abundant but has large effects on an ecological community

indicator species

a plant or animal species that, by its presence, abundance, scarcity, or chemical composition reflect the conditions of the ecosystem around it