APES Unit 2: Module 8

Genetic diversity

A measure of the genetic variation among individuals in a population

Population bottleneck

When a large population declines in number, the amount of genetic diversity carried by the surviving individuals is greatly reduced

Species diversity

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

Habitat diversity

The variety of habitats that exist in a given ecosystem

Specialists

Species that only live under a narrow range of biotic or abiotic conditions

Generalists

Species that can live under a wide range of biotic or abiotic conditions

Ecosystem diversity

The variety of ecosystems that exist in a given region

Species richness

The number of different species in a given area

Species evenness

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

How does biodiversity exist at different scales?

Biodiversity exists as genetic diversity, species diversity, habitat diversity, and ecosystem diversity. All four scales of biodiversity contribute to the overall biodiversity of the planet

How does biodiversity affect responses to environmental stressors?

The various scales of biodiversity have impacts on how populations and ecosystems respond to justice or abiotic environmental stressors. High genetic diversity benefits the long-term persistence of populations because they are better able to respond to environmental change. High habitat diversity favors the persistence of habitat specialists, which have very narrow habitat requirements. High species diversity leads to increased primary productivity and increased stability in ecosystems

How can we calculate biodiversity?

Biodiversity can be quantified in terms of species richness and evenness

How can we estimate the number of species living on earth?

Scientists are not able to determine the exact number of species on earth. Most estimates agree on approximately 10 million species, of which we have identified approximately 2 million