What is the main source of energy for all living things?
Radiation from the sun (solar or light energy).
What is biomass?
Biomass is the dry mass of living material in an animal or plant.
Why is the amount of biomass at each stage of a food chain lass than it was at the previous stage?
• Not all organisms at one stage are eaten by the stage above • Some material and energy taken in is passed out as waste by the organism • Respiration and synthesis reactions of the organism
What is a producer?
A producer can make complex compounds from simpler inorganic molecules.
What is a herbivore?
A herbivore is an organism that only eats plants.
What is a carnivore?
A carnivore is an animal that eats a diet consisting mainly of meat.
Energy loss in waste:
• Some animals cannot digest all the parts of an animal that they eat, therefore some biomass is lost as faeces • When an animal eats more protein than it needs, the excess is broken down. It gets passed out as urea in urine
Energy loss in movement:
• Parts of the biomass eaten by an animal is used for respiration inside its cells • Movement uses a great deal of energy, the muscles use energy to contract so biomass is lost by respiration of cells in the muscles
Keeping a constant body temperature:
Animals use energy to maintain a constant body temperature. Animals use energy to keep warm or to cool down.
What organism breaks down waste, dead animals and plants after they die?
What happens in the process of decomposition?
The nutrients and other minerals are returned to the environment. The same material is recycled over and over again.
What are decomposers?
Decomposers are a group of micro organisms that include bacteria and fungi. They feed on waste droppings and dead organisms.
What are detritus feeders?
Detritus feeders such as maggots and some types of worms often start the process of decay. They eat dead animals and produce waste materials. The bacteria and fungi then come in to digest everything. Some of the nutrients they receive are used for reproduction and growth while the rest is released as waste products.
What are the waste products of decomposers?
Carbon dioxide, water and nutrients that plants use.
Why is the decay process important?
The decay process is important as it releases substances that plants need to grow.
Decay in warm/cold conditions:
Chemical reactions in micro organisms work faster in warm conditions. They slow down and might even stop if the conditions are too cold. However, in very hot conditions, the enzymes may denature and stop working.
Decay in moist conditions:
Most micro organisms grow better in moist conditions. The moisture makes the micro organisms dissolve their food with ease and it also prevents the micro organisms from drying out.
Decay with oxygen:
Most micro organisms need oxygen to release energy, grow and reproduce which is why decay takes place quicker when there is plenty of oxygen available.
Uses of decay:
Decomposers are vital for recycling resources in the natural world. In sewage treatment plants, micro organisms are used to break down the bodily waste we produce. In compost heaps, decomposing micro organisms break down grass cuttings and vegetable peelings which leaves a substance that can be used as a fertiliser.
What is the carbon cycle?
The carbon cycle is the constant cycling of carbon in nature.
What are the main molecules in our body based on?
These molecules are based on carbon atoms combined with other elements.
Photosynthesis and carbon:
Photosynthesis is one of the main ways which leads to carbon dioxide being taken out of the environment. Plants use carbon dioxide and sunlight to make carbohydrates, fats and proteins. The carbon then gets passed on to the animal that eats the plant.
Respiration and carbon:
Respiration is one of the main ways which leads to carbon dioxide being returned back into the environment. The carbon released is then taken back by growing plants in the form of carbon dioxide for photosynthesis.
Combustion and carbon:
Fossil fuels contain carbon which was locked away by photosynthesising organisms millions of years ago. When fossil fuels are burned, the carbon is released back into the atmosphere.
Compost heap features:
Compost heaps should have holes so that micro organisms can respire and have access to oxygen. Moreover, warm and moist conditions should be provided to maximise the speed of decay. Mixing the compost heap also helps air get in.
Carbon Cycle Diagram: