Organisms are well
adapted to survive in their
normal environment.
To survive and reproduce, organisms require a
supply of materials from their surroundings and
from the other living organisms there.
Plants often compete with each other for light and space, and for water and nutrients
from the soil. Animals often compete with each other for food, mates and territory.
Organisms, including microorganisms have
features (adaptations) that enable them to survive
in the conditions in which they normally live.
Some organisms live in environments that are very extreme. Extremophiles
may be tolerant to high levels of salt, high temperatures or high pressures.
Animals and plants may be adapted for survival in the conditions where they normally live, eg
deserts, the Arctic. Animals may be adapted for survival in dry and arctic environments by
means of: changes to surface area; thickness of insulating coat; amount of body fat;
camouflage. Plants may be adapted to survive in dry environments by means of: changes to
surface area particularly of the leaves; water-storage tissues; extensive root systems.
Animals and plants may be adapted to
cope with specific features of their
environment; thorns, poisons and warning
colours to deter predators.
B1.4.2 Environmental Change
Population size depends on a variety of factors including competition,
predation, disease and human influences. Changes in the
environment may affect the distribution and behaviour of organisms.
Changes in the environment affect the distribution of living organisms.
Animals and plants are subjected to environmental changes. Such changes may be caused by living
or non-living factors such as a change in a competitor, or in the average temperature or rainfall.
Living organisms can be used as indicators of pollution. Lichens
can be used as air pollution indicators, particularly of the
concentration of sulfur dioxide in the atmosphere and invertebrate
animals can be used as water pollution indicators and are used
as indicators of the concentration of dissolved oxygen in water.
Environmental changes can be
measured using non-living
indicators such as oxygen levels,
temperature and rainfall.