AQA Double Science B1 Part 2: Competition & Environmental Change

Everything you will need to know about comptetition between plants and animals, and how this affects their population.

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What plants compete for

In order to survive and reproduce, plants compete with other plants for:

- Light (needed for photosynthesis)

- Water (also needed for photosynthesis)

- Space (enough space to grow in)

- nutrients (absorbed from within the soil)

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What animals compete for:

Just like plants, animals also compete for resources in order to survive. These are:

- Water

- Food

- Mates

- Territory (where the animal lives)

A good example of animals that compete with each other are the red and grey squirrels. Grey squirrels are more resistant to diseases and are much more larger in weight and size in comparison to the native red squirrels. Therefore, the grey squirrel population increases and the red squirrel population declines.

Survival of the fittest, in other words...

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Living factors that cause environmental change

The habitats in which plants and animals live change all the time. Living indicators are a contributing factor to this such as:

- A change in the population of predators

- A change in the number of food sources

- Types of competitors could vary in number

- A change to how often diseases are caught

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How non-living factors cause environmental change

Just like living factors, non-living factors also cause changes in the environment such as:

- Changes in temperature (weather, humidity...)

- A change in average rainfall

- A change in the level of air or water polution

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How environmental changes affect the populations

Increase in population: maybe more food resources are available and there is a decrease in the population of predators

Decrease in population: maybe chemicals such as pesticides have a negative effect on animals, there may be less food resources, maybe there are more diseases going around, predator population has increased, lake water could have been acidified and this could have a negative effect on the sea creature population...

Distribution changes: a change where an organism lives due to seasonal changes and temperature changes.

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Measuring environmental change using living indica

Living Indicators:

Air pollution can be monitored by looking at particuar types of lichen. These lichen are very sensitive to the level of sulphur dioxide in the atmosphere (ie. lot'f of lichen=very clean air).

Water pollution can be monitored by looking at rat-tailed maggots and sludgeworms. A high population of these two creatures indicates a high level of water pollution.

Other species, such as mayfly larvae are the complete opposite to rat-tailed maggots and sludgeworms because they only live in water where it is very clean.

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Mesuring environmental change using non-living ind

Non-living Indicators:

Satellites - used to measure the temperature of the sea surface nd amount of snow and ice cover.

Automatic weather stations - tell us the atmospheric temperature in various locations.

Rain gauges - measure rainfall and to measure how much the average rainfall changes year on year.

Dissolved oxygen meters - measure concentration of dissolved oxygen in water.

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