7 1 adaptations interdependence and competition

A population is a group of organisms of the same species living in the same place at the same time.

A community includes all of the populations living in the same area at the same time.

True. The place where an organism lives is its habitat, e.g. a meadow or a woodland.

False. Living organisms interact with both the living components (each other) and the non-living components (e.g. the temperature and rainfall) of their environment.

An ecosystem is all of the organisms that live in an area, and their interactions with the living (biotic) and non-living (abiotic) factors in their environment.

False. It is plants that compete for light, space, water and minerals. Animals compete for food, mates and territory.

Interdependence refers to the fact that organisms living in the same habitat depend on each other. A change in one species will affect other species.

A community is considered stable when the living and non-living components of the ecosystem are balanced; this results in population sizes that remain constant.

Abiotic factors are the non-living factors that influence ecosystems, e.g. temperature, sunlight, pH, salinity, precipitation.

Examples of abiotic factors include:

A decrease in water availability might affect a population of living organisms as follows:

True. An increase in temperature from 20-30 °C will increase the rate of photosynthesis in plants, so it is likely that the plants will grow faster and the population size will increase.

False. Competition is a biotic factor as it is a living factor that affect organisms in an ecosystem.

Biotic factors are the living factors that affect organisms in an ecosystem, such as competition, predation and disease.

Biotic factors that could affect populations include:

False. A decrease in the size of a prey population will most likely result in a decrease in the size of a predator population. This is because there will not be enough food so predators will die, or leave.

Competition occurs when organisms fight for the same resources, e.g. food or mates

True. Competition is likely to reduce the size of a competing population. In extreme cases a less well-adapted population may die out.

An adaptation is a feature that improves an animal's ability to survive in its natural environment.

A desert plant may have the following structural adaptations:

False. Large ears is a structural adaptation. Functional adaptations are physiological or biochemical and so would include features such as sweating or shivering in thermoregulation.

A behavioural adaptation is any behaviour which increases the chances of survival, e.g.

True. Small ears in arctic foxes are a structural adaptation to minimise heat loss as they provide a smaller surface area to volume ratio compared to larger ears.

An extremophile is an organism which lives in an extreme environment, e.g.