Biology Class Test - Energy and Nutrient Transfer 5.0 / 5 based on 1 rating ? BiologyEnergy flow through ecosystemsGCSENone Created by: nobleaCreated on: 21-10-15 17:17 Why does a food chain always start with a producer? Producers can make their own food from simple substances. Green plants use sunlight as a source of energy. 1 of 15 What do we call many food chains interconnected? A food web. 2 of 15 What happens to the number of individuals as you go up a pyramid of number? It decreases. 3 of 15 Why is it often more accurate to record biomass rather than the number of individuals, for example, in the case of an oak tree? Biomass tells you how much living material there is and so gets over the problem of size. 4 of 15 What do energy pyramids show? The amount of energy transferred from one trophic level to the next (in kJ/m2/year). 5 of 15 Not all sunlight falling on a leaf is absorbed and used. Why? Some is reflected, some passes through the leaf and some light that is absorbed cannot be used for photosynthesis. 6 of 15 Not all food eaten by an animal goes to form new tissue. Why? Some is 'lost' in urine and faeces; some is used in respiration. 7 of 15 What is decomposition? The rotting away of dead plants and animals by microbes. 8 of 15 What is a detritivore? A small animal that feeds on pieces of dead, decaying matter (detritus). 9 of 15 How do decomposers like soil bacteria and fungi break down dead remains? They release enzymes to digest the dead matter and then absorb it. 10 of 15 What is the detritivore in this food chain: dead animal > blowfly maggot > blackbird > owl. The blowfly maggot. 11 of 15 Give 3 ways in which carbon dioxide gets in the air. By plants and animals respiring, by burning fossil fuels, by the activities of decomposers. 12 of 15 Nitrogen is needed to make proteins in plants. In what form is it taken up? Nitrates. 13 of 15 What sort of bacteria convert nitrogen in the air into nitrates? Nitrogen-fixing bacteria. 14 of 15 What sort of bacteria convert ammonia in the soil into nitrates? Nitrifying bacteria. 15 of 15
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