Population ecology

Overconsumption is a situation where resource use has outpaced the sustainable capacity of the ecosystem.

A logistic function or logistic curve is a common "S" shape (sigmoid curve), with equation: where * e = the natural logarithm base (also known as Euler's number), * x0 = the x-value of the sigmoid's midpoint, * L = the curve's maximum value, and * k = the steepness of the curve.

Although scientists observed reduction in populations of several European amphibian species since the 1950s, awareness of the decline of amphibian populations and its classification as a modern-day global mass extinction only dates from the 1980s.

In biology, population growth is the increase in the number of individuals in a population.

A population is a summation of all the organisms of the same group or species, which live in a particular geographical area, and have the capability of interbreeding.

Colony collapse disorder (CCD) is the phenomenon that occurs when the majority of worker bees in a colony disappear and leave behind a queen, plenty of food and a few nurse bees to care for the remaining immature bees and the queen.

The birth rate (technically, births/population rate) is the total number of live births per 1,000 of a population in a year.

Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time.

A two-child policy is a government-imposed limit of two children allowed per family or the payment of government subsidies only to the first two children.

A polyphenic trait is a trait for which multiple, discrete phenotypes can arise from a single genotype as a result of differing environmental conditions.

The world's energy resources can be divided into fossil fuel, nuclear fuel and renewable resources.

Population dynamics is the branch of life sciences that studies the size and age composition of populations as dynamical systems, and the biological and environmental processes driving them (such as birth and death rates, and by immigration and emigration).

Overpopulation occurs when a species' population exceeds the carrying capacity of its ecological niche.

A fishery is an area with an associated fish or aquatic population which is harvested for its commercial or recreational value.