biology B1 (3)

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  • Created by: haidee
  • Created on: 28-04-12 14:35
  • Long term changes in the environment can produce changes in the distribution of many species
  • Plant and animals may become more common in a particular area or they may die out

Where are all the bees?

  • Honeybees are dying out because of a disease called colony collapse disorder CCD is affecting large numbers of bee colonies all over the world
  • CCD is a viral disease spread by a parasitic mite, varsoa
  • The changes in distribution of bees is linked to:
  • -changing temperatures
  • -pesticides
  • -altering flower patterns due to changing climate
  • Honeybees are important for farming and to the environment:
  • -pollinating flowers, allowing flowers to reproduce
  • -pollinate fruit crops and other crops
  • -make honey

Energy and nutrient transfer

  • Organisms need for energy to move, keep warm etc
  • Organisms need food for growth, as it provides proteins, fats etc that are needed to build new cells
  • Biomass is the mass of living material
  • The source of all energy for living things is sunlight
  • Food chains begin with energy form the sun
  • The first organism is a plant which makes food using light energy, carbon dioxide and water by the process photosynthesis
  • Because the first organism make food it is known as the producer
  • The arrows in a food chain show the transfer of energy and materials to the next organism in the chain
  • Each step in the chain is called a feeding or trophic level
  • The animal which eats the plant is known as the primary consumer
  • The secondary consumer will be at the third trophic level in the chain
  • The top consumer is usually a predator and the animal it eats is its prey
  • A food web is made up of interconnected food chains

Using and losing energy

  • The amount of material and energy contained in the biomass of an organism at each stage in the food chain is less than it is at the previous stage
  • This is because:
  • -not all the organisms at one stage are eaten by the stage above
  • -some of the material and energy is passed out as waste by the animal
  • -only a small proportion of the food taken in is used to produce new tissue
  • -much of the food taken in is used in respiration and heat is given off as a waste product
  • -the energy is then used for movement
  • In food production it is more efficient to use plants and herbivores as food materials than carnivores
  • The further up the food chain you go the more energy has been lost to the environment

Efficient food production

  • A lot of energy is lost along a food chain and we are top carnivores
  • The human population is over 6 billion and rising
  • It takes a lot of land to provide enough grazing for beef cattle
  • This can be improved by:




is this ocr gcse?

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