B4.1 Ecosystems Flashcards
Give 3 molecules which are cycled through ecosystems
Oxygen, carbon dioxide and water
Briefly describe how water is cycled through an ecosystem
- Water evaporates from rivers and lakes and from transpiration
- Water condenses as clouds
- Water is returned through precipitation
Briefly describe how carbon dioxide is cycled through an ecosystem
- Carbon dioxide is fixed through photosynthesis
- Respiration releases carbon dioxide
- Decomposition releases carbon dioxide
- Combustion releases carbon dioxide
Briefly describe how nitrogen is cycled through an ecosystem
- Nitrogen is fixed by lightning, the Haber process and bacteria
- Denitrifying bacteria release nitrogen back to the atmosphere
Why is recycling in ecosystems necessary?
- To create a continuous flow of nutrients
- To provide fresh water
How would a decrease in oxygen availability affect the rate of decomposition?
- Lack of oxygen causes microorganisms to respire anaerobically
- Anaerobic decay is slower than aerobic decay
How would a change in temperature affect the rate of decomposition?
- A decrease in temperature slows the rate of the decomposition reactions
- A large increase in temperature will denature enzymes, slowing or even stopping decomposition
Give 4 abiotic factors that affect communities
- Light intensity
- Temperature
- Soil pH
- Moisture levels
Give 4 biotic factors that affect communities
- Number of predators
- Food availability
- Disease
- Human activity
What are the 3 types of interdependence?
Mutualism, parasitism and predation
What is parasitism?
- Where one organism lives on another and takes nutrients from the other organism
- This is beneficial to the parasite and detrimental to the host
What is mutualism?
- Two organisms depend on each other
- Both of the organisms benefit from the
relationship
Give 4 things animals compete for
- Mates
- Space
- Food
- Water
Give 4 things that plants compete for
- Light
- Water
- Minerals
- Space
What is a producer?
An organism that makes its own food
