Patterns of biodiversity in ecological communities

Question 1

Factors most tightly correlated with biodiversity?

Answer 1

geographic location and size

Question 2

What is biogeography?

Answer 2

• Affects biodiversity within ecological communities
• Aims to understand the processes that shapes the spatial patterns in biodiversity

Question 3

2 key factors that shape biodiversity:

Answer 3

Location and habitat size/area

Question 4

Largest scale patterns is…

Answer 4

A gradient biodiversity associated with latitude

Question 5

What drives equatorial - polar gradients?

Answer 5

• Solar energy inputs (amount of energy that hits earth’s surface)
• Water availability
• Moisture
• Evolutionary history

Question 6

Tropical communities are older and more established and have more species meaning…

Answer 6

• Things grow year round
• Less seasonality
• Rate of life is faster
• Smaller impact of ice ages and glaciation

Question 7

What is a key driver od latitudinal diversity gradients?

Answer 7

Climate

Question 8

What are the most important features of climate?

Answer 8

Water availability and solar radiation

Question 9

Evapotranspiration

Answer 9

Solar input and water availability measures

Question 10

What is actual evapotranspiration determined by?

Answer 10

Solar radiation

Question 11

What is potential evapotranspiration?

Answer 11

A measure of solar radiation independent of water availability
Means we can measure water and energy using the same units

Question 12

Species-area relationship

Answer 12

Early 1800’s - found larger geographic areas contain more species
One of first general patterns of biodiversity described by natural historians

Question 13

Why size-area relationship?

Answer 13

• larger areas contain greater habitat diversity
• support larger populations
• reduce likelihood of local extinction

Question 14

Species diversity within a community is a result of what?

Answer 14

Equilibrium between species gain and species loss
balances of forces = equilibrium

Question 15

island equilibrium model identified 2 key determinants of species diversity

Answer 15

Isolation and Size

Question 16

Why do smaller islands/habitats have have a higher extinction rate?

Answer 16

They contain fewer resources and support smaller populations
Competition for resources with more species

Question 17

High rates of immigration and low rates of extinction mean what?

Answer 17

large, connected islands are likely to have lots of species constantly arriving and constantly going extinct