Ecosystems 23.1 Flashcards
What is an ecosystem?
All the living organisms that interact with each other in a defined area. This could be a small bacteria colony or a desert.
Who defines the boundaries of an ecosystem?
The person studying the ecosystem
Why are ecosystems described as ‘dynamic’?
They are constantly changing because of the environment and the living organisms in it
What kind of factors can affect an ecosystem?
Abiotic factors and biotic factors
What biotic factors affect an ecosystem?
Biotic factors are living factors.
- the presence of certain organisms
- the size of the populations
- the competition between two populations for food or space
What abiotic factors affect an ecosystem?
Abiotic factors are non-living or physical factors.
- Amount of rainfall or sunlight
- Temperature range
What do animals compete for?
Food, space, mates
Why is light an abiotic factor?
Plants heavily depend on light availability as they need to photosynthesise, the more light the greater success of the plants.
How can plants adapt to less light availability?
- They can have larger leaves where there is less light for bigger surface area.
- They can produce photosynthetic pigments that need less light
- Their reproductive systems can change to only work when light is at its optimum
Why is temperature an abiotic factor?
Temperature affects the rate of enzymes that control metabolic reactions. Plants will grow more rapidly in warm temperatures as will ectothermic animals that can’t regulate their internal blood temperature. Changes in temperature also trigger migration or hibernation in some species.
Why is water availability an abiotic factor?
If water is not available it leads to water stress in both plants and animals. If plants don’t have water, they wilt as their cells aren’t turgid and it is also needed for photosynthesis. Cacti have adapted to cope with water stress.
Why is oxygen availability an abiotic factor?
If plants live in waterlogged soil, they will have no oxygen available. In aquatic environments, there needs to be cold flowing water so that the organisms have oxygen available. If the temperature is too high or the flow of water isn’t fast enough, the organisms can suffocate.
What are edaphic soil factors?
Edaphic soil factors are just what type of soil the organisms can survive in as soil can have different particle sizes.
- Clay has fine particles and can easily be waterlogged
- Loam has different sized particles and retains water instead of becoming waterlogged
- Sandy has course separated particles which allows water to drain and so isn’t retained.
