Food Chains Shows the feeding relationships between organisms in a habitat
Composition of food chains • Begins with a PRODUCER -usually a plant • The source of the energy for the food chain is the SUN • The PRIMARY CONSUMER (herbivore) eats the producer • The SECONDARY consumer (carnivore) eats the primary etc • The chain finishes with a top carnivore.
Pond Food Chain algae Water flea Damsel fly nymph Dragon-fly nymph
Beech Wood Habitat Sparrow Hawk Beech leaves aphids Blue Tit
Predator Prey Relationships Rabbit population rising-few predator foxes to eat them Falling rabbit population- less vegetation to eat, More predator foxes to eat them Fox population falling-fewer rabbit Prey to eat Fox population rising Lots of rabbit prey to eat
Sunny meadows simulation • http://puzzling.caret.cam.ac.uk/game.php?game=foodchain%20
Transfer of Energy • Energy is transferred in food • Not all the energy taken in by an organism is available to the next organism in the chain
Energy loss: • Loss in faeces • Not all of an organism is eaten (roots, bones) • Organism uses its energy, released by respiration, for movement etc
How much energy is transferred? • Only 10 % of what an organism gets is passed on • This means that there are fewer organisms in each link of the chain • Chains are never longer than 5 links
Food Webs. • Food chains imply that an organism only eats one type of organism • Webs show the variety of foods eaten and are more realistic of the feeding relationships in a habitat.
Pyramids • Pyramid of Numbers- show the numbers of organism found in each level of the food chain • Pyramid of Biomass- shows the DRY MASS of the organisms at each level
Concentration of chemicals in the food chain. • Chemicals are concentrated up a food chain and can reach lethal levels in the top carnivore • It happens because each consumer eats many of the organisms which each have the chemical in them