Biology · C Interaction and interdependence. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.
A population is all the individuals of one species in an area. A community is all the populations living together. We can rarely count every individual, so we estimate from samples, which must be random to avoid bias.
A population in a new habitat grows slowly, then exponentially, then levels off. The level it stays at is the carrying capacity, the largest population the environment can support. Growth is slowed by density-dependent factors such as competition, predation and disease, which get stronger as the population gets more crowded.
Members of a community affect each other through competition, predation, herbivory, parasitism, pathogenicity and mutualism.
In the Lincoln index students divide by the wrong number. Divide by R, the marked animals found in the second sample, not by the unmarked ones.
Answer: About 300 snails.
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