BSC 385 Lecture Notes - Lecture 23: Biogeography, Allopatric Speciation, Ecological Stability

• School: University of Alabama
• Department: Biological Sciences
• Course: BSC 385
• Professor: Carla Atkinson

Document Summary

A plot of the log proportional abundance of each species as a function of its abundance. The slope of this curve is a measure of community evenness- higher slope, less even. Difficult measures of species diversity: total species richness, threatened species richness, endemic species richness. Five mass-extinction events in earth"s history: end ordovician, late devonian, end permian, end triassic, end cretaceous. Species diversity and area are related: s = caz. Where s is the number of species, a is the area, z is the slope of the line and c is a constant. Ecological stability (charles elton): dynamic stability: stable communities are those in which the variation in community function is small and centered on an equilibrium value, reaction to perturbation: Resistance, the tendency of a system not to change when disturbed. Resilience, the ability of the system to recover from disturbance. Testing the relationship between species diversity and stability. Hypothesis: high species diversity increases the stability of the community.