Card Set Information
communities rank abundance curves environmental complexity food webs
Covering Chs 16-18 Ecology textbook, and lecture
What is a community and its structure?
- an association of interacting species inhabiting some defined area
- includes number of species, relative abundance of species, and type of species
Species diversity depends on...?
Species evenness, and species richness
Higher in more complex environments with many niches
What does rank abundance curves show?
Shows both components of species diversity - species evenness and richness
Flatter rank abundance curve with lower slope indicates greater species evenness
If comparing 2 species, the one that extends farther has greater species richness
What does spatial heterogeneity do in an environment?
Spatial heterogeneity can affect the coexistence of 2 or more species
If nutrients are low in one place, but high in another, spatial heterogeneity can allow the species to coexist
Alpha vs Beta diversity
- each community might have similar diversity within its boundaries
- diversity may stay the same (alpha), but encounter new species
Intermediate disturbance hypothesis
Intermediate levels of disturbance promotes higher diversity
Without disturbance, competitive exclusion operates
With too much disturbance, only a few r-selected species with rapid colonization and life cycles inhabit
Results in homogenization of communities, reducing beta diversity
Food webs and trophic biology
refers to the feeding relationships in communities
Relationships are often depicted as food webs, which present feeding hierarchies as trophic levels
Direct vs. Indirect Interactions
involve effects of one species on another without the influence of a third (parasitism, herbivory, predation)
- where one species affects another through a third species