Population Ecology Flashcards
Population density
It is the number of individuals of a species per unit of area or volume at a given time.
Random dispersion
Unpredictably spaced
Clumped dispersion
Clustered in specific parts of the habitat.
Uniform dispersion
Evenly spaced.
Changes in population size are produced by…
Natality, mortality, inmigration and emigration.
Growth rate (r)
It is the rate of change on a per capita basis. On a global scale r = b - d.
Intrinsic rate of increase (rmax)
It is the maximum rate at which a species or population could increase in number under ideal conditions.
Exponential growth
Certain populations exhibit an accelerated pattern of growth (the J-shaped curve), but eventually the growth rate decreases to around zero or becomes negative.
Logistic population growth
It is represented as a S shape line.
Carrying capacity (K)
It is the largest population that can be maintained for an indefinite time by a particular environment.
Density-dependent factors
They regulate population growth by affecting a larger proportion of the population as population density rises. Predation, disease and competition are examples.
Density-independent factors
They limit population growth but are not influenced by changes in population density. Hurricanes and blizzards are examples.
Semelparous
Species that expend their energy in a single immense reproductive effort.
Iteroparous
Species that exhibit repeated reproductive cycles throughout their lifetimes.
Type I survivorship
Mortality is greatest in old age.
