Populations Flashcards
Population
Number of individuals of a species living in a particular place at a particular time.
Distribution
Regions in which a species is found.
Abundance
Number (of a species) in a specific area at any time.
Population Density
Number of an individual species living in a particular place at a particular time per unit area.
Random Distribution
An unpredictable spacing of individuals; where the position of each individual of a species is independent of the other individuals of the species in a given environment.
Evenly Spaced Distribution
A distribution where individuals are more or less equally spaced throughout the entire area.
Clumping
Distribution where individuals are found clustered in groups in particular parts of the habitats.
Population Growth Rate
The rate of change in a population over a particular range of time.
Population Growth
Increase in the size of a population in a particular habitat over time.
Density- Independent Factor
An abiotic factor (that is independent of the density of the population) that affects the size of a population.
Limiting Factors
Conditions that limit the growth, abundance or distribution of an organism or a population of organisms.
r-Strategists
A species that occupies unstable environments and uses the evolutionary strategy of maintaining a high growth rate, occupying less-crowded ecological niches, and producing many offspring.
K-Strategists
A species whose population fluctuates at or near the carrying capacity (K) of the environment in which it resides.
Biofilm
A layer on a soil matrix composed of microscopic bacteria algae and protozoa in a complex polymer-linked assemblage.
Density-Dependent Factor
Any factor influencing population regulation that has a greater impact as the density increases.
Competition
Rivalry between individuals, f the same or different species, for specific resource(s).
Competitive Exclusion Principle
Two species are unable to compete for the resources in the same niche.
Niche
A species role in its environment; a species interactions with the biotic and abiotic factors of its environment.
Character Displacement
The evolutionary divergence of characteristics displayed by two or more species with the same niche in a particular habitat.
Resource Partitioning
Division of environmental resources by coexisting species populations to avoid competition for resources.
Environmental Limiting Factor
Any factor that limits the growth of a population.
Biotic Potential
Number of offspring capable of being produced by individuals of a species.
Carrying Capacity
The total population of all environmental limiting factors.
Environmental Resistance
Sum total of all environmental limiting factors.
J-Shaped Population Curve
The graphical representation of the change in population density of an organism as it increases rapidly and the stops suddenly, due to environmental or other factors.
S-Shaped Population Curve
The graphical representation of the change in population density of an organism when it initially increases slowly and then rapidly as it approaches an exponential growth rate, but the decreases and levels off as the environmental carrying capacity is reached.
Equilibrium (Set Point)
Point at which a system can be maintained, e.g. population size for a specific environment.
Ecological Homeostasis
Maintenance of a population size commensurate with environmental limiting factors, mediated by feedback systems.
