B17 - Organisising An Ecoystem (Y11 - Spring 2) Flashcards
🟢 How can Feeding Relationships within a Community represented
Feeding relationships within a community can be represented by food chains. All food chains begin with a producer which synthesises molecules. This is usually a green plant or alga which makes glucose by photosynthesis.
🟢 What are Food Chains And What Orders Are They In
- Each stage in the food chain is called a trophic level, the arrows represent a flow of energy and matter through the food chain.
- A food chain will always start with a photosynthetic producer, e.g green plants, algae, plankton, e.c.t. They are capable of producing organic compounds from inorganic compounds
- All other organisms are consumers, i.e they gain their energy and matter through eating other organisms.
🟢 What’s Eaten by What in Food Chains
Producers are eaten by primary consumers, which in turn may be eaten by secondary consumers and then tertiary consumers.
🟢 Why are Food Chains Always Relatively Short
Food chains have poor energy efficiency which means energy losses take place at each stage, which is why there are so little food chains that span over 6 or 7 organisms (as the energy being passed down becomes less and less)
🟢 How do the Number of Predators Rise and Fall in Linked Cycles?
In a stable community the numbers of predators and prey rise and fall in linked cycles.
- If there is plenty of food avaliable, the prey animals grow and reproduce successfully, so numbers increase.
- As prey animal numbers go up, there is plenty of food availabke for the predators, so predators can reproduce successfully and predator numbers increase.
- The high number of predators eat a larger
proportion of the prey animals, so prey numbers fall. - With fewer prey animals, there is less food for the predators, so they are less successful and predator numbers fall.
- With the reduction in predators, and the good
supply that results from fewer animals, prey numbers go up again and the cycle repeats itself.
(This is only true in a stable community)
🟢 What are Predators and What are Prey
Consumers that kill and eat other animals are predators, and those eaten are prey.
🟢 What Is a Stable Community
A stable community is one where all of the biotic and abiotic factors are in balance.
🟢 How Can a Predator-Prey Cycles Change?
The cycles would change if something changed in the community, for example a drought happened, or a new predator arrived, then predator prey cycle would start to change.
🟢 Explain what is happening after the Predatir population is decreasing in a predator-prey cycle
The prey population is starting to increase because the predator population is low. This means that more of the prey population can survive and reproduce, as their birth rate will be faster than their death rate, allowing the prey population to grow again..
🟢 What Does Anaerobic Decay Produce
Anaerobic decay produces methane gas. Biogas generators can be used to produce methane gas as a fuel.
🟢 What Are The 3 Conditions Needed For Decay
- Temperature
- Moisture
- Oxygen
🟢 What Temperature Conditions are Needed for Decomposition
The speed at which things decay depends partly on the temperature. Chemical reactions in microorgnaims, like those in most living things, work faster in warm conditions. They slow down and might even stop if the conditions are too cold. Decay also stops if it gets too hot, as the enzymes in the decomposers are denatured and/or kill the microbes.
🟢 What Moisture Conditions are Needed for Decomposition
Most microorganisms grow faster in moist conditions. The moisture makes it easier for them to digest their food and also prevents them from drying out. So the decay of dead plants and animals - as well as leaves and dung - takes place far more rapidly in warm, moist conditions than does in cold, dry ones.
🟢 What Oxygen Conditions are Needed for Decomposition
Although some microorganisms are anaerobic, most decomposers respire aerobically. This means they need oxygen to break down food and transfer energy, grow, and reproduce. This is why decay takes place more rapidly in aerobic conditions when there is plenty of oxygen avaliable.
🟢 What Do Gardeners Use Decay For?
Gardeners and farmers try to provide optimum conditions for rapid decay of waste biological material. The compost produced is used as a natural fertiliser for growing garden plants or crops.
🟢 What does Anaerobic Decay Produce?
Anaerobic decay produces methane gas. Biogas generators can be used to produce methane gas as a fuel.
🟢 How does Decay make Compost
We can use the process of decay to make compost. Decomposers will break down our waste kitchen and garden plant material to make a brown, crumbly substance. The compost is full of nutrients released by the decomposers. This process takes from a few months to over a year. The compost forms a good, natural fertiliser.
🟢 What is the point/use of Compost
Compost, or well-rotted manure provides fertiliser for the soil, returning valuabke minerals, and also improving soil structure and water retention.
🟢 Does the way Compost is made differ between gardens and farm, and can Compost be made with and/or without oxygen?
Whether done in the garden, or on a large farm, the principles of composting are the same. Compost can be made with or without oxygen
🟢 What Happens if Compost is Made With Oxygen
If the microorganisms have oxygen, they respire aerobically and transfer energy to their surroundings, killing off weed seeds and speeding up the process.
(The warmer the compost mixture, the faster the compost will be made (up to about 70° when decomposition stops). The decay process is also faster in moist conditions that in dry ones.)
🟢 What Happens if Compost is Made Without Oxygen
Without oxygen, the process does not cause a rise in temperature and is slower.
(The warmer the compost mixture, the faster the compost will be made (up to about 70° when decomposition stops). The decay process is also faster in moist conditions that in dry ones.)
🟢 What happens when Bacteria decompose waste Material in Anaerobic conditions?
When bacteria decompose waste material in anaerobic conditions they produce methane. Methane is a flammable gas which can be used as fuel for vehicles.
🟢 What are Biogas Generators and How Do They Work
Plant and/or animal waste is put into special vessels known as biogas generators and in anaerobic conditions decomposers produce methane gas for use as a fuel. The bacteria involved in methane production work best at a temperature of around 30°C, so biogas generators tend to work best in hot climates. However, the process transfers energy to the surroundings because the reactions are exothermic. This means that if you heat the mixture at the beginning to start things off, and have your generator well insulated to prevent cooling, biogas generators will work anywhere.
🟢 How can we use the Process of Anaerobic Decay to Provide us with Fuel?
We can use the process of anaerobic decay or decomposition to provide us with fuel. Together the methane and carbon dioxide produced are called biogas. This is a source of renewable energy.
