Food chains and food websIB MYP Sciences: Mind map

Exam questions on Food chains and food webs

1. On a grassland in Kenya, grass is eaten by grasshoppers. The grasshoppers are eaten by lizards, and the lizards are eaten by eagles. Ecologists draw this as a food chain with arrows between the organisms.
   Explain why the grass is called the producer in this food chain.2 marks
2. A freshwater pond in Hungary contains algae, snails, tadpoles, dragonfly larvae, sticklebacks (small fish), a heron, bacteria and fungi. Snails and tadpoles feed on the algae. Dragonfly larvae eat tadpoles. Sticklebacks eat both snails and dragonfly larvae. The heron eats the sticklebacks. Bacteria and fungi live on the dead remains and waste of all the other organisms.
   Explain why the decomposers are important in the pond.2 marks
3. Ecologists in a national park in Canada counted the snowshoe hares and the lynxes (large wild cats that hunt hares) in the same forest for seven years. The hare population was 40 000, 80 000, 120 000, 70 000, 30 000, 25 000 and 60 000 in years 1 to 7. The lynx population was 10 000, 12 000, 25 000, 50 000, 60 000, 35 000 and 15 000 in the same years.
   Describe the pattern shown by the hare and lynx populations.3 marks