Week 1 Part 1 Flashcards
What are communities
Groups of interacting species that occur together at the same place and time
Which ways are communities usually defined
Physically or Biologically
What is taxonmic affinity
Bird species in a community
What is guild
Group of species that use the same resources
What is functional group
Species that function in similar ways, but do not necessarily use the same reosurces
What are the different trophic interactions
Primary producers
Primary consumers (herbivores)
Secondary consumers
Tertiary consumers
What are the shortcomings of trophic interactions
tell us little about the strength of interacations of their importance in the community
Some species change feeding status they mature
Some species are omnivores feeding on more than on the trophic
Do food webs include non-trophic interactions
NO you can not see horiziontal interacations such as competitiion
What web morea ccurately descirbes the trophic levels
Interacations Webs shows the vertical and horizontal interactions than a traditional food web
What are the three things that can be described community structure
Species richness- the number of species in a community
Species evenness - relative abundane compared with one another
Species diversity - combines species richenns and species evenness
Does a high species richness mean that it is diverse
NO
What is the shannon index
pi = proportion of individuals in the ith species
s = number of species in the community
What is biodiversity
Describes diversity from genes to species to ecosystems
What is the rank abundance curves
Plot the proprotional abundance of each species relative to the others in rank order
What is species composition
Refers to the identity of species in a community
What is species accumulation curves
Species richness is plotted as a function of the total number of individuals that have been counted
What can the species accumulation curve help determine
When most or all of the species in a community has been observed
What is direct interacation
Occur between two species ( competition, predation and facilitation)
What are indirect interactions
Occur when the relationship between two species is mediated by a third species
What is a trophic cascade
Can result from indirect interactions so a carnivore eats a herbivore but then the decrease herbivore abundance has a positive effect on the primary producer
What is trophic facilitation
A consumer is indirectly facilitated by a positive interaction between its prey and another species
What are competitive networks
Competitive interactions among multiple species in which every species negatibely interacts with every other species
What is hard with competitive networks
Diffcult for one species to dominante
What is interaction strength
Magnitude of the effect of one species on the abundance of another species
How is interacation strength measured
Removing one spcies (the interactor species) from the community and observing the effect on the other species (the target species)
What are foundation species
Have large effects on other speices and thus species diversity usualu because of there considerable abundance or biomass
What are ecosystem engineers
They create modify or maintain physical habitat for themselves and other species
What are keystone species
Have a strong effects because of their roles in the community there effect doesnt reley on their proportion or biomass
