Ecology - Community Structure Final Flashcards
How might interspecific competition play a role in shaping communities in nature?
determines how many and which species coexist in a community
Give two predictions about the interactions of potential competitors within a community
Potential competitors that coexist in a community should, at the very least, exhibit some form of niche differentiation
Potential competitors with little niche differentiation should be unlikely to coexist
Which of these predictions was supported by Pyke’s work with alpine bumblebees in Colorado?
Potential competitors that coexist in a community should, at the very least, exhibit some form of niche differentiation
What is a feeding guild
a group of species that exploits the same type of resource in a similar way
What is niche complementarity?
species that occupy a similar position along one dimension of the niche will tend to differ along another!
How might predators enhance community diversity?
prey on competitively dominant species and thereby prevent competitive exclusion
what happened when Paine removed the starfish predator
barnacles took over
what could be used to characterize/classify a “keystone predator”
seeing a community seeming to be organized around it
How might a predator serve as a vehicle for transmission of a parasite?
Parasite can live in or on the side of them while they live and can influence host behavior to increase their own transmission (allowing paratsite with complex living cycle can move from one place to another)
In what ways might a parasite alter the behaviour of its host?
Cause them to engage in certain prey to eat or go to certain places like water
also make them become more available to prey so that they are killed by a predator and then they die
What is parasite-mediated competition?
Paratistes influence biodiversity when they alter the outcome of competitive interactions between host species
How might a tolerant host species cause an indirect negative effect on a second, less tolerant host species?
occurs when a tolerant host species amplifies a parasite’s abundance, causing an indirect negative effect on a second, less tolerant host species
How might a microparasite facilitate a biological invasion?
reducing local biodiversity by eliminating populations of one host species
How might a parasite contribute to biodiversity?
by allowing a competitively inferior species to coexist with a dominant species
How might a parasite lead to a reduction in biodiversity?
mass population declines or even extinctions
Under what conditions might the effects of parasitism on ecological communities be most pronounced?
when the hosts are keystone or dominant species with important functions in an ecosystem`
Give an example of how the introduction of a parasite caused a dramatic change in ecosystem structure.
sea urchins in the Caribbean experienced a massive die-off associated with microbial pathogens, eliminating the keystone roles of urchins as grazers on coral reefs
How do grasslands and some conifers depend on fire for their survival?
To prevent the establishment of trees and shrubs and the fire allows them to open their cones to disperse their seeds
What types of biomes have evolved under regular fires
Mediterranean-type shrublands of the southwest (chaparral)
African savannas and southern pinelands
How can fires set succession back?
Favor fire resistnact species , eliminate competing for soil moisture and nutrients from fire sensitive and shade tolerant trees
How do fires act as “sanitizers”?
terminating outbreaks of insects and parasites
What kinds of things make trees more susceptible to wind throw?
Trees whos trunk lack the suppleness of youth are especially vulnerable of wind throw
Trees growing on shallow drained shoils who roots are not well anchored and threatened by diseases, lightening strikes, hurricanes, tornadoes, and heavy rain, land slides and mudslides
What are some environmental problems associated with over grazing by animals?
If overdone, it can lead to denudation, soil erosion or invasion by less desirable species
How might beavers be considered ecosystem engineers?
Beavers (system engineers) alter the landscape by creating ponds from flowing streams
