Ecosystems, populations and nichesAQA A-Level Biology: Mind map

Exam questions on Ecosystems, populations and niches

1. A woodland contains oak trees, caterpillars, blackbirds, mites that live on the blackbirds, and fungi and bacteria in the soil. The woodland also has non-living components such as soil pH, light intensity and temperature.
   Explain the difference between a community and an ecosystem.2 marks
2. Two species of barnacle live on a rocky shore. Species X is found on the upper shore, where it is exposed to air and drying out for long periods. Species Y is found on the lower shore, which is covered by the sea for most of the time. When species Y was removed from an area of the lower shore, species X spread into that area and survived there. When species X was removed from the upper shore, species Y still did not survive there.
   Explain why species X is found only on the upper shore.2 marks
3. In a northern forest, the population of snowshoe hares rises and falls in a cycle. The population of lynx, which prey on the hares, follows the same cycle about a year later. The hares feed on young plant shoots and twigs.
   Explain how an increase in the hare population leads to changes in the lynx population and then in the hare population.3 marks