Communities

What are the four characteristics of a community

Species composition and richness, diversity, food web

Species diversity

Combines richness and evenness of species

Define species richness and evenness

Number and relative abundance

Entropy

Uncertainty of encountering a random variable

What two factors increase entropy

Large number and equal proportion

There are 5 species in two different habitats, where they are scattered in one and equally proportioned in the other. How are these habitats different and how are they the same?

They have the same richness but differ in evenness

What quantifying coefficient is used in the Shannon-Weiner Index of Diversity?

H’

What would the minimum value of H’ = 0 represent?

Low richness with a single species

Disturbance

Event that kills or damages organisms allowing others to grow and reproduce

What promotes the highest level of diversity

Intermediate level of disturbance

What is common during low disturbance

Competitive exclusion

What is common during high disturbance

Increased mortality

What is the significant factor of the Intermediate Disturbance Hypothesis

Sufficient time between disturbances allowing colonization

What degree of disturbance is widely caused by humans, what does this threaten?

High levels , endangered species