B17. Organising an ecosystem Flashcards
Define population
A species that occupy the same habitat
Define habitat
The place in which an organism lives
Define community
Populations of different species interacting
Define ecosystem
The interactions between the biotic and abiotic factors
Define biomass
The total mass of living material
Describe a simple food chain
producer ➡ primary consumer ➡ secondary consumer ➡ tertiary consumer
What is a producer
An organisms that makes its own food
What types of organisms are primary producers?
Photosynthetic organisms like green plants and algae that trap energy from the sun.
What is a primary consumer?
An organism that feeds on producers
What is a secondary consumer?
An organism that feeds on primary consumers
What is a tertiary consumer?
An organisms that feeds on secondary consumers
What is a predator?
A consumer that kills and eats other animals
What is prey?
An animal that is killed and eaten by another animal
Describe the pattern of predators and prey in a stable community
The numbers of predators and prey rise and fall in cycles
Describe how materials cycle through the living and non-living components of an ecosystem?
Organisms take in elements from their surroundings
Elements converted to complex molecules which become biomass
Elements transferred along food chains
Elements returned to environment during excretion and decomposition of dead organisms
Give 3 molecules which are cycled through ecosystems
Oxygen, carbon dioxide and water
Describe the carbon cycle?
Plants fix carbon dioxide into organic molecules during photosynthesis
The organic carbon-containing molecules are passed onto organisms that eat the plants
Carbon dioxide is released back into the atmosphere by respiration from animals and plants
Burning fossil fuels also releases carbon dioxide into the atmosphere
Why is the carbon cycle important
Carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells
Describe the water cycle
Water from lakes and oceans evaporates
The evaporated water condenses into clouds and returns to earth as precipitation
The water from precipitation is useful for life on land
The water then returns to rivers and oceans through surface runoff
Why is the water cycle important?
Living organisms require water and the water cycle provides organisms on land with a continuous supply of water
Why is microorganisms important for the cycling of materials through an ecosystem?
Microorganisms return carbon to the environment by releasing carbon dioxide through respiration while they decompose dead matter. The decomposition of dead matter in soil returns mineral ions to the environment for other organisms to use
What is meant by decomposition?
The breakdown of dead materials into simpler organic matter
How do decomposers break down dead matter?
Decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules
What are the two types of decomposition?
Aerobic decomposition
Anaerobic decomposition
What factors affect the rate of decomposition?
Oxygen availability
Temperature
Water content
Why is oxygen required for decomposition?
Most decomposers require oxygen for aerobic respiration
How does the availability of oxygen affect the rate of decomposition?
As oxygen levels increase the rate of decomposition increases.
As oxygen levels decrease, the rate of decomposition decreases
Why can decomposition still occur in the absence of oxygen?
Some decomposers respire anaerobically
How does soil water content affect the rate of decomposition?
Decomposers require water to survive:
In moist conditions the rate of decomposition is high
In waterlogged soils there is little oxygen for respiration so the rate of decomposition decreases
Why does decomposition require water?
Water is required for the secretion of enzymes and absorption of dissolved molecules
How does the temperature affect the rate of decomposition?
Rate highest at 50°C
Lower temperatures, enzymes work too slowly, rate decreases
High temperatures, enzymes denature, decomposition stops
How is the rate of change calculated when considering the decay of biological material?
Rate of change = change in value ÷ change in time
What is compost?
The nutrient-rich product of the rapid decay of waste biological material in optimum conditions set by gardeners and farmers
How is compost used?
Used a natural fertiliser to promote growth of crops or garden plants
Describe how biogas generators work
Biogas generators provide methane gas for fuel through anaerobic decomposition that occurs in animal waste
