Populations

Science

The number of males and females of different ages in a population

Age structure

The number of males and females of different ages in a population. Age structure. Age structure is the distribution of people of different ages within a population, which helps scientists understand population dynamics and predict future trends.

Number and variety of species living in an area

Biodiversity

Number and variety of species living in an area. Biodiversity. Biodiversity is the variety of all life forms on Earth, including plants, animals, and microorganisms.

The largest population that an environment can support

Carrying capacity

The largest population that an environment can support. Carrying capacity. It is the maximum number of living organisms an environment can sustain indefinitely without being degraded.

A population changing from high birth and death rates to low birth and death rates

Demographic transition

A population changing from high birth and death rates to low birth and death rates. Demographic transition. It is the process where a society transitions from high rates of births and deaths to lower rates as it develops economically.

The study of human populations, their growth rate and distribution

Demography

The study of human populations, their growth rate and distribution. Demography. It is the science that analyzes how populations change over time and space.

A limiting factor that depends on the population size, for example, a large population needs more to hunt

Density dependent factor

A limiting factor that depends on the population size, for example, a large population needs more to hunt. Density dependent factor. In simple terms, a density dependent factor is a natural control on population growth that becomes stronger as the population size increases, like competition for resources.

A factor that limits population growth independent of population size, for example a cold climate

Density independent factor

A factor that limits population growth independent of population size, for example, a cold climate, is a density-independent factor. In science, a density-independent factor affects a population's growth regardless of how many individuals are in the population.

A movement of individuals out of a population

Emigration

A movement of individuals out of a population. Emigration. In science, emigration is when individuals leave a population to live elsewhere.

A dramatic population increase in a short time

Exponential growth

A dramatic population increase in a short time. Exponential growth. In science, exponential growth means numbers double over regular intervals, rapidly increasing in size.

The movement of individuals into a population

Immigration

The movement of individuals into a population. Immigration. In science, immigration refers to the process where new organisms enter and join a different population or ecosystem.

A species critical to the survival of an ecosystem

Keystone species

A species critical to the survival of an ecosystem. Keystone species. A keystone species is an organism that plays a vital role in maintaining the structure and balance of an ecosystem.

An environmental factor that limits population growth, for example, a drought

Limiting factor

An environmental factor that limits population growth, for example, a drought. Limiting factor. A limiting factor is something that restricts the size or rate of a population's growth.

When population growth starts slow, then sees exponential growth, then slows again

Logistic growth

When population growth starts slow, then sees exponential growth, then slows again. Logistic growth. Logistic growth is when a population grows quickly at first, then slows down as resources become limited and carrying capacity is reached.

all the organisms of the same species living in the same area

Population explained in an easy to understand way.

The number of individuals per unit of area

Population density

The number of individuals per unit of area. Population density. It is a measure of how many people live in a specific area.