Biogeography and biodiversity

Question 1

Geographic/location effects

Answer 1

One of largest scale patterns is a gradient in biodiversity associated with latitude
Evolutionary history - tropical communities are older (longer growing sessions, high temp, results in more generations)
Climate is likely the key driver of latitudinal diversity gradients
Solar input and water availability measured in terms of evaporation

Question 2

Actual Evapotranspiration

Answer 2

Determined by solar radiation and water

Question 3

Potential evapotranspiration

Answer 3

a measure of solar radiation independant of water availability

Question 4

Size/Area effects

Answer 4

Larger geographic areas contain more species. Called the Species - Area relationship
Lots of potential reasons, eg larger areas contain greater habitat diversity, support larger populations, reduce likelihood of local extinction

Question 5

The Island Equilibrium Model

Answer 5

Species diversity within a community is a result of the equilibrium between species gain and species loss. Model identified two key determinants of species diversity: Isolation and Size
Smaller islands/habitats are likely to contain fewer resources and support small populations, thus extinction rate is likely to be high. Isolated islands likely to gain fewer species by immigration. High rates of immigration and low rates of extinction mean that large connected islands are likely to have lots of species

Question 6

Design of habitat protection

Answer 6

Has to consider the size of protected areas and connectivity between habitats. The species area relationship, rates of extinction and immigration, population size, all inform (in theory) the design of protected areas