Variation, classification and adaptation

Variation

  • All living things vary in the way they look or behave.
  • Living things that belong to the same species are all slightly different.
  • Living things that belong to different species are so different that they cannot reproduce together.
  • Inheritance, the environment or a combination of both may cause these differences.

Classification

  • Living things are divided into kingdoms.
  • There are six main kingdoms – virus, bacterium, protist, fungus, plant and animal.

Characteristics

  • We vary partly because of the random way our characteristics are inherited.
  • The environment can affect most of our characteristics.
  • It is usually a combination of genetics and environment that determines how we look and behave.
  • Some characteristics are not affected by the environment.

Ecology

  • Plants and animals interact with their environment to create habitats.
  • Ecology is the study of these interactions.
  • The world is divided into a number of large regions called biomes.
  • Each biome is characterised by a particular climate.

Biomes

  • Tundra biomevery cold
  • Coniferous forest biomecold
  • Temperate forest biomevaried but cool
  • Grassland biomedry
  • Savannah biomedry
  • Desert biomevery dry
  • Tropical rainforest biomehot and wet

Habitats

  • The place where a plant or animal lives is its habitat.
  • Some habitats are very small and are called microhabitats.
  • A habitat has to supply all the needs of the animals and plants that live in it.
  • The animals and plants that share a habitat are locked together in an interdependent community. They form a food web which is dependent on the energy from the sun.

Adaptation

  • In a community, the animal or plant best adapted to its surroundings will survive.
  • Predators have adapted to survive by being strong, agile and fast. They have good vision and often a camouflaged body. They may also hunt in packs, have a variety of prey, and frequently hunt the young, sick and old.
  • Prey have also adapted: the best adapted escape and breed. Prey may be able to run, swim or fly fast. They often stay in large groups. They may have a horrible taste. They may have warning colours or camouflage.

Competition

  • Populations cannot keep growing out of control.
  • Animals have to compete for space, food and water in their struggle to survive.
  • Only those fitted to the opportunities and limitations of their environment will survive – survival of the fittest.
  • Plants compete for space, light, water and nutrients.
  • If a living organism can adapt to its environment then it will survive and breed.

Limiting factors

  • Amount of food and water available
  • Predators or grazing
  • Disease
  • Climate, temperature, floods, droughts, storms
  • Competition for space, mates, light, food and water
  • Human activity such as pollution or destruction of habitat.