Ecology Flashcards
What is carrying capacity (K)?
The maximum population size that a particular environment can sustain.
How does K vary over time?
K varies over time and space as limiting factors vary (e.g. energy, shelter, predation, nutrient availability, water, suitable nesting sites).
In the logistic population growth model, how is the per capita rate of increase related to carrying capacity?
The per capita rate of increase declines as carrying capacity is reached, so growth rate declines when the population size gets large.
How is the logistic model different from the exponential model?
The logistic model starts with the exponential model and adds an expression that reduces per capita rate of increase as N approaches K.
When does growth begin to slow in the logistic growth model?
At about half the carrying capacity.
What are the assumptions of the logistic growth model?
- Density-dependent factors affect populations.
- Populations adjust growth instantaneously and smoothly as they approach K
- Each individual added to the population has the same negative effect on its growth rate.
What is a biological community?
An assemblage of populations of various species living close enough for potential interaction.
What are interspecific interactions?
Relationships between species in a community. (Ex: competition, predation, herbivory, symbiosis (parasitism, mutualism, and commensalism), and facilitation)
What does the competitive exclusion principle say?
This principle states that two species competing for the same limiting resources cannot coexist in the same place. Simply put, no two species can occupy the same niche and can only co-exist if they occupy different niches.
What is an ecological niche?
The total of a species’ use of biotic and abiotic resources–an ecological niche can also be thought of as an organism’s ecological role.
What is resource partitioning?
Species evolve to minimize competition by “partitioning” their resources.
What is a fundamental niche?
A species’ fundamental niche is the niche potentially occupied by that species.
What is a realized niche?
A species’ realized niche is the niche actually occupied by that species.
Why would a species’ fundamental niche differ from its realized niche?
Because of competition and spatial partitioning.
How does character displacement work?
Morphological similarity and use of resources tend to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.
