Interdependence and Adaptation

Interdependence and Adaptation

1. Survival

   • • To survive, organisms require a supply of materials from their surroundings and from the other living organisms there.
     • • Organisms live, grow and reproduce in places where, and at times when, conditions are suitable.

2. Competition

   • Animals often compete with each other for:
     • • Food
       • • Mates
         • • Territory
   • Plants often compete with each other for:
     • • Light
       • • Water from the soil
         • • Nutrients from the soil

3. Adaptation

   • • Organisms have features (adaptations) which enable them to survive in the conditions in which they normally live
   • • The organisms that are best adapted to make use of their resources in a habitat are more likely to survive and increase in numbers
   • • For example:
     • o To be able to obtain a certain food better.
       • o To make it more difficult for predators to catch them.
         • o To survive in extreme climates, eg arctic or deserts
           • • Plants lose water vapour from the surface of their leaves
             • • It is essential that they have adaptations which minimise this.

4. Extreme adaptations:

   • • Extremophiles are organisms that live in extreme environments.
   • • Some may be tolerant to high levels of salt, high temperatures or high pressures.
   • • Animals and plants may be adapted to cope with specific features of their environment eg thorns, poisons and warning colours to deter predators.

5. Extreme Animals

   • • Animals may be adapted for survival in dry and arctic environments by means of:
     • o changes to surface area
       • o thickness of insulating coat
         • o amount of body fat
           • o camouflage.
   • • Examples:
     • o Camel
       • • The camel can go without food and water for 3 to 4 days.
         • • Fat stored in their humps provides long term food reserve, and a supply of metabolic water.
           • The fat is not distributed around the body; this reduces insulation, allowing more heat loss.
             • • They are tall and thin, increasing their surface area to volume ration, increasing heat loss by radiation.
     • o Polar Bear
       • • Polar bear has thick fur and fat beneath its skin to insulate it.
         • • Their large, furry feet help to distribute their weight as they walk on a thin ice.
           • • They are white which camouflages them against the snow. This helps them to hunt.
             • • They are compact in shape, reducing their surface area to volume ratio; this reduces heat loss by radiation

6. Extreme Plants

   • • Plants may be adapted to survive in dry environments by means of:
     • o changes to surface area, particularly of the leaves
       • o water-storage tissues
         • o extensive root systems.
   • • Desert plants
     • • Eg the cactus, require very little water to survive
       • • Leaves are spines.
         • • Spines guard against most browsing herbivorous animals.
           • • Spines also reduce their surface area, reducing water loss by evaporation
             • • A thick waxy coating surrounds the plant to reduce evaporation.
               • • Fewer 'stomata', reducing water loss
                 • • Roots tend to spread sideways to catch rain water.
   • • Arctic plants
     • • Many of the plants are small, growing close to the ground and very close together to avoid the wind and conserve heat.
       • • Some possess a light, fuzzy covering to insulate the buds so they can grow.
         • • Many are dark colors of blue and purple to absorb the heat from the sunlight even during the winter months.
           • • Because of the cold and short growing seasons, arctic plants grow very slowly.

7. Microorganisms

   • • Microorganisms have adaptations that enable them to survive in different environments.
     • • Some microorganisms have flagella which enable them to move around quickly.
       • • Bacteria undergo rapid reproduction when conditions are favourable.

8. Environmental change

   • • Changes in the environment affect the distribution of living organisms.
     • • For example, the changing distribution of some bird species and the disappearance of pollinating insects including bees.
   • Non-living (abiotic) factors:
     • • Light
       • • Oxygen
         • • Water
           • • Temperature
   • Living (biotic) factors:
     • • Food
       • • Predation
         • • Grazing
           • • Disease
             • • Competition – for: food, light, water, space.

9. Living organisms can be used as indicators of pollution:

   • • Lichens are sensitive to changes in air quality.
     • • They are very sensitive to sulphur dioxide (SO2) pollution in the air.
       • • Some species only grow in non-polluted air. Some species grow in polluted air. These lichens can be used as air pollution indicators.
         • • Invertebrate animals are sensitive to changes in the concentration of dissolved oxygen in water.

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