A decrease in the population growth rate (r or λ) as the population density decreases.
Limitation of the abundance of a population by nutrient supply or by the availability of food. Compare top-down control.
A pattern of population fluctuations where the extent to which the population rises and falls in abundance gradually become smaller over time.
delayed density dependence
Delays in the effect of population density on population size that can contribute to population fluctuations.
Chance events associated with whether individuals survive or reproduce.
Erratic or unpredictable changes in the environment.
The breaking up of once continuous habitat into a complex pattern of
spatially isolated habitat patches amid a matrix of human-dominated
Mating between related individuals.
isolation by distance
A metapopulation pattern in which habitat patches located far away from occupied patches are less likely to be colonized than are nearby patches.
A long-distance dispersal event by which a species colonizes a new geographic region.
A set of spatially isolated populations linked to one another by dispersal.
An extreme environmental event such as a flood, severe windstorm, or outbreak of disease that can eliminate or drastically reduce the sizes of populations.
A pattern of population fluctuations in which alternating periods of high and low abundance occur after nearly constant intervals of time.
The most common pattern of population growth, in which population size rises and falls over time.
An extremely rapid increase in the number of individuals in a population.
A tendency for high rates of immigration to protect a population from extinction.
stable limit cycle
A pattern of population fluctuations in which abundance cycles indefinitely.
Limitation of the abundance of a population by consumers. Compare bottom-up control.
A process in which competition causes the phenotypes of competing species to evolve to become more different over time, thereby causing the species to become more different where they live together than where they live apart.
A constant used in the Lotka–Volterra competition model to describe the extent to which an individual of one competing species decreases the per capita growth rate of the other species.
An interaction between individuals of two species in which each is harmed by their shared use of a resource that limits their ability to grow, survive, or reproduce (a –/– relationship).
competitive exclusion principle
The principle that two species that use a limiting resource in the same way cannot coexist indefinitely.
An interaction in which species compete indirectly through their mutual effects on the availability of a shared resource. Compare interference competition.
An interaction in which species compete directly by performing antagonistic actions that interfere with the ability of their competitors to use a resource that both require, such as food or space. Compare exploitation competition.
Lotka–Volterra competition model
A modified form of the logistic equation used to model competition.
A feature of the environment that affects organism function and population growth rates but is not consumed or depleted.
The use of limiting resources by different species in a community in different ways.
A feature of the environment that is required for growth, survival, or reproduction and which can be consumed or otherwise used to the point of depletion. Compare physical factor.
zero population growth isoclines
Lines derived from the Lotka–Volterra competition model marking the conditions under which a population does not increase or decrease in size.
aposematic coloration See warning coloration.
warning coloration- A defense against predators in which prey species that contain powerful toxins advertise those toxins with bright coloration; also called aposematic coloration.
An adaptive growth response of plants to herbivory in which removal of plant tissues stimulates the plant to produce new tissues.
A defense against predators in which prey species have a shape or coloration that provides camouflage and allows them to avoid detection.
A relationship in which one organism benefits by feeding on, and thus directly harming, another.
An organism that eats the tissues or internal fluids of living plants or algae.
In plant–herbivore interactions, a defense against herbivory, such as production of a secondary compound, that is stimulated by herbivore attack.
A defense against predators in which prey species resemble less palatable organisms or physical features of their environment, causing potential predators to mistake them for something less desirable to eat.
An insect that lays one or a few eggs on or in a host organism (itself usually an insect), which the resulting larvae remain with, eat, and almost always kill.
predator An organism that kills and eats other organisms, referred to as its prey.
An organism that kills and eats other organisms, referred to as its prey.
An organism eaten by a predator.
A chemical compound in plants not used directly in growth, and often used in such functions as defense against herbivores or protection from harmful radiation.
A predator that hunts by remaining in one place and attacking prey that move within striking distance.
Change in the size of a population that is rapid at first, then
decreases as the population approaches the carrying capacity of its environment.
The maximum population size that can be supported indefinitely by the environment, represented by the term K in the logistic equation.
The total area of productive ecosystems required to support a population.