Lecture 4 Flashcards
Guild?
Species that use the same resource
Functional group?
Species that function in similar ways.
Community structure?
The set of characteristics that shape communities.
Species composition?
The contribution of one species to the environment.
Species richness?
The number of species in a community.
Species evenness?
The relative abundance when comparing different species.
Rank abundance curve x, y? (2•)
•y = Proportional abundance
•x = Abundance rank (species richness)
What does the slope of a rank abundance curve mean?
Evenness.
Species accumulation curve (x,y)?
x = sampling effort (# of individuals)
y = number of species in samples (species richness)
Species area relationship?
Species richness increases with area sampled.
What can increase species richness? (2•)
•Immigration
•Speciation
What can decrease species richness?
•extinction
Equilibrium model of biogeography (x,y)?
x = species richness
y = rate for immigration and rate for extinction
I > E?
dS/dt > 0
I < E?
dS/dt <0
S{eq}?
When I = E
When is the immigration rate the highest?
In a region with few species.
When is the extinction rate the highest?
In a region with a lot of species.
When can the extinction rate change?
When the size of the region changes.
When can the immigration rate change?
When the region moved or other regions moved closer.
The probability of immigration and extinction depends on?
The species already present.
S{eq} depends on?
The balance between immigration and extinction.
Theory of island biogeography?
How species diversity as they disperse across islands.
Biogeography?
The study of species composition and diversity across geographic locations.
????What drives the Latitudinal diversity gradient??????
•Patterns of species richness are controlled by rates of speciation, extinction, and dispersal.
•Dispersal rates are similar everywhere, then species richness should reflect a balance between extinction and speciation.
Productivity of carrying capacity hypothesis?
Some regions may have a higher carrying capacity.
Cradle Hypothesis?
Diversification rate = speciation rate - extinction rate.
Diversification rate hypothesis?
More stable and large regions may have higher diversification rates.
Diversification time hypothesis?
More stability for a longer period of time and more species evolution, thus the rate of diversification is higher.
