Lecture 25: Community Assembly Flashcards
How does a con biologist vs ecologist approach species diversity?
Con bio: is a species present? keep abundant species abundant!
Ecologist: how do ecological conditions influence communities?
Community structure: define trophic cascade
Interaction in which predator of a predator benefits the producer indirectly
Community structure: define trophic facilitation
- Indirect effect where one species benefits another via positive interaction (mutualism)
- Direct interactions in trophic cascade are the negative predator-prey interactions
Define ecological networks
A set of ecological interactions within a community
Ex: trophic networks, host-parasitoid networks, mutualistic networks
Guild vs functional group
Guild: species that share a similar resource
Functional group: species that share a function, but not necessarily a resource
Explain detritivores
Consumer material to break it down
Explain biomass pyramids
Compared to a food web, this shows the abundance of specific trophic levels
What’s unique about a keystone species?
If they disappear, no other species can fill their role (low functional redundancy)
They help keep prey populations below “K” thus, reducing competition, creating ecological niches, and increasing diversity within communities.
How do predators increase diversity?
When predator species in the community are increased, local species diversity also increases (Robert Paine)
What are umbrella species?
Species selected to represent their ecosystem when conservation plans are being made
What are ecosystem engineers?
The activity of a species alters the habitat - do not alter trophic effect
Ecosystem engineers: allogenic vs autogenic
Allogenic: modifies the materials in their environment (woodpeckers and beavers)
Autogenic: modifies the environment by modifying themselves (kelp forests and trees)
