biology B1 (3)

• 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:
• …