Lecture 19: Chapter 15- Community Structure Flashcards
Population vs community
-a population is a group of INDIVIDUALS of the same species inhabiting a given area
-a community is a group of SPECIES inhabiting a given area and interacting, directly or indirectly
Biodiversity
Richness (vs abundance)
-Richness (S)= number of species
-Abundance=number of individuals
relative abundance
-proportion of each species relative to the total number of individuals of all species living in the community
(pi=ni/N)
proportion of individuals= number of individuals of specific species/total number of individuals of all species
evenness
how equally individuals are distributed among the species
similarity
keystone species
Be able to construct and read a rank-abundance curve and calculate similarity (Sorensen Coefficient of Community)
-rank on x axis and relative abundance on the y axis
-allow you to estimate the biodiversity of the community
-the longer the curve, the greater the species richness in the community
-the more gradual the slope, the greater the species evenness in the community
CC= (2c)/(S1+S2)
Zonation
-change in physical and biological structures of communities as seen when moving across the landscape
Organismal vs continuum community (theory and usage)
-organismal: communities are known as associations. they consist of species that belong together and develop toward a climax stage (maturity)
-relatively constant species composition
-distribution that is characteristic of a particular habitat
-individualistic (continuum) community: species exist together in a community because they have similar requirements and happen to be there at the same time
-species distributions along environmental gradients are the result of the independent responses of individual species and do not form clusters
-transitions are gradual and difficult to identify
