Adaptation

3.4 Sexual reproduction

4.2 Natural selection

Adaptation

  1. Competition

    1. To survive and reproduce, organisms require a supply of materials from their surroundings and other living organisms there

    2. Plants

      1. Plants often compete with each other for light, space and water & nutrients from the soil
      2. In woodland, some smaller plants flower before the trees are in leaf so that they get enough light, space, water and nutrients
      3. Some plants have deep roots that can reach underground water better than those with shallow roots
      4. Some plants spread their seeds over a wide area so that they do not compete with themselves by using animals, the wind or mini-explosions1

    3. Animals

      1. Animals often compete with each other for food, mates and territory
      2. An animal’s territory must be large enough to find water & food and breed
      3. Predators compete with their prey to eat them
      4. Predators & prey may be camouflaged so that they are less easily spotted by the other
      5. Prey compete with each other to esape from predators and find food
      6. Some animals may be poisonous and have warning colours so that they are not eaten

  2. Adaptation

    1. Organisms, including microorganisms, have features that enable them to survive in the conditions in which they normally live
    2. Extremophiles live in environments that contain high levels of salt, temperatures or pressures

    3. Adaptation types

      1. Structural adaptations, such as the ways in which organism are shaped or coloured
      2. Behavioural adaptations, such as migration
      3. Functional adaptations, such as those related to processes such as reproduction and metabolism

    4. Plants

      1. Plants need to collect & conserve water
      2. Some have an extensive root system for water collection
      3. Some have small or waxy leaves to minimise water loss from stomata
      4. Some have a swollen stem to store water
      5. In dry conditions such as deserts, some plants, such as the cactus, have become adapted to conserve water and some, such as the mesquite tree, have become adapted to collect water
      6. Some are adapted to stop animals from eating them by developing thorns, poisonous chemicals and warning colours

    5. Animals

      1. Their mouthparts are adapted to their diet, depending on whether they are a herbivore or carnivore
      2. Animals in cold climates, such as the Arctic, have thick fur and blubber, fat under the skin, to keep them warm
      3. Some, such as the Arctic fox & the Arctic hare, are camouflaged: white in the winter and brown in the summer
      4. Some animals are big so that they have a smaller volume-to-surface-area-ratio for heat loss
      5. In hot, dry climates such as deserts, animals are adapted to conserve water and lose heat, some hunting or feeding at night to remain cool during the day

  3. Parasites

    1. Parasites are adapted for living on or inside their hosts

    2. Fleas

      1. They live amongst the hair of mammals
      2. They have sharp mouth parts to suck blood
      3. Their body is flattened so they are not easily dislodged
      4. Their body is hard so they are not damaged when the mammal scratches
      5. Their hind legs are long so they can jump from host to host

    3. Tapeworm

      1. They live in the intestines of animals
      2. They have suckers & hooks to fix themselves to the wall of the intestine
      3. Their body consists of flattened segments mainly producing many eggs
      4. They have no gut and their flattened shape provides a large surface area for the absorption of soluble food from the host gut
      5. They have a thick outer cuticle to protect them from the host’s digestive enzymes

    4. Malaria parasites

      1. They are single-celled organisms2 that cause malaria in humans and have different forms that are specialised for living in a different place
      2. Gametocytes infect mosquitoes when the mosquito sucks blood containing them, maturing into gametes that fertilise to form zygotes that pass into the salivary glands and develop into sporozoites
      3. Sporozoites are passed onto humans when the mosquito bites and injects its saliva into the blood vessels, travelling with the blood to the liver and enter the liver cells, where some divide and become thousands of merozoites
      4. Merozoites are released from the liver and into the blood, where they enter the red blood cells and some turn into schizonts
      5. Schizonts burst the red blood cells, releasing more merozoites; this release coincides with the fever attack seen when a person has malaria
      6. Some merozoites in the blood cells enter a sexual phase of reproduction and produce gametocytes, which can be transferred to a mosquito when it bites
  1. This is called ballochory ↩
  2. They are called plasmodium ↩