Ecosystems
Applied Science: BTEC Level 3 National Extended Diploma, topic 5.1.8
Organisms in Ecosystems
Ecosystems are made up of living (biotic) and non-living (abiotic) things in a specific area. The organisms in ecosystems can be classified based on their roles:
Producers
- Producers use light energy from the Sun to make their own food.
Consumers
- Consumers can't make their own food. Instead, they get their energy by consuming other organisms (producers or other consumers).
Decomposers
- Decomposers (e.g. bacteria, fungi) recycle organic matter within an ecosystem. They're crucial for the ecosystem function of nutrient cycling:
- Through decomposition, nutrients are put back into the soil.
- Plants take up these nutrients as food. These plants may go on to be eaten by consumers.
- When plants or consumers die, the nutrients are returned to the soil.
Environmental Changes and Their Impact
Environmental change affects the distribution (spread) of species, and in extreme cases, their longevity (how long they survive). Such environmental changes include:
Temperature
- Polar bears hunt seals on floating sea ice.
- Increasing temperatures cause this ice to melt. This means that the polar bears are no longer able to hunt their main food source.
Water
- Wildebeests migrate annually from the Serengeti plains of Tanzania Northwards into Kenya to track seasonal changes in rainfall patterns.
Atmospheric gases
- Carbon dioxide dissolves in water and increases the water acidity.
- Acidic water hinders corals' ability to build a skeleton. This means that the increased carbon dioxide in the atmosphere prevents coral growth.
Causes of Environmental Changes
Environmental changes can come about for many different reasons, including:
Seasons
- Many countries have rainy and dry seasons.
- The difference in temperature between winter and summer drives birds on worldwide migrations.
Humans
- Through the burning of fossil fuels, humans increase the atmospheric concentration of greenhouse gases.
- People can change water availability through the building of large dams. The pollution of water sources can make them toxic to wildlife.
Geological activity
- Volcanic eruptions change the composition of atmospheric gases.
- Storms and droughts change the availability of water.
Test yourself on Ecosystems
Organisms in Ecosystems
Nutrient Cycling
Which of the following is not an example of how geographic activity can cause environmental change?