B1.4 Interdependence And Adaptation

B1.4 Interdependence And Adaptation

1. B1.4.1 Adaptations

   • 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.

2. 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.