Population Ecology Keywords

Biosphere

The part of the Earth where organisms are found.

Ecosystem

Made up of groups of different species that interact with each other and the environment.

Organism

An individual form of life, composed of a single cell or complex cells that are capable of growing and reproducing.

Community

A group of different species that inhabit and interact in a particular area.

Species

A group of closely-related organisms that are similar to each other and are usually capable of interbreeding and producing fertile offspring.

Individual

A single organism that is capable of independent existence.

Population

A group of organisms of the same species that occupy the same area can freely breed with each other and produce fertile offspring.

Demographics

The study of characteristics of a population, such as age, gender, income, education, and ethnicity, is used to analyze and understand social trends, consumer behaviour, and target marketing strategies.

Natality

The birth rate in animals and production of seeds in plants.

Mortality

Death rate

Immigration

Individuals moving into a population and staying.

Emigration

Individuals moving out of a population and not returning.

Environmental resistance

The sum of environmental factors that limit the growth of a population

Carrying capacity

The maximum number of individuals that an environment can sustainably support.

Stable population

A population where the numbers will decrease when its size exceeds the carrying capacity but will exceed when numbers fall below the carrying capacity.

Unstable population

Develops if the population far exceeds the carrying capacity. This causes the habitat to deteriorate rapidly until it eventually is not able to support the population. Numbers will decrease rapidly and lead to extinction.

Competition

When two or more species/individuals compete for the same resources that are in short supply.

Intraspecific competition

Competition that occurs between individuals of the same species.

Interspecific competition

Competition that occurs between individuals of different species.

Niche

All the conditions necessary for an organism to survive and reproduce.

Specialisation

The structural and behavioral adaptations that enable individuals of different species to co-exist.

Competitive exclusion

When one of the two competing species is more successful.

Competitive co-existence

When two competing species co-exist in the same habitat.

Resource partitioning

When species with similar requirements evolve specialized traits that help them utilize resources differently.

Ecological Succession

The predictable pattern of gradual change over time in the type of species in a community, following a disturbance.

Primary succession

Begins on sites that previously had no soil.

Secondary succession

Begins in areas where soil still remains after a disturbance.

Stratification

Resource partitioning where plants divide the use of resources by creating a vertical structure that divides the vegetation into layers.

Social organisation

The structure of relationships within a group

Dilution effect

The greater the number of individuals, the greater the survival chances are of an individual.

Confusion and distraction effect

When a herd or flock scatters to all directions, confusing the predator.

Eusocial

Species that exhibit the highest level of social organisation