Practise IB ESS SL 2.1.10 by defining carrying capacity, tracing limiting factors and predicting how population pressure changes resources, habitats and sustainable numbers.
Outline four ways in which changes in the population of one species may reduce the carrying capacity of an environment for another species.
a. growth of a predator/carnivore population may reduce carrying capacity (cc) for a prey species;
b. prey species may decline, reducing cc of predator;
c. introduction/increased population of a competitor species would reduce the cc of other competing species / increased human population encroaching on habitats results in reduced cc of many species;
d. spread of a parasite/pathogen/disease organism may reduce cc for a given host species;
e. a host species may decline, reducing cc for pathogen;
f. growth of a herbivore population may reduce cc of a plant species;
g. a plant species may decline thus reducing cc for herbivore species;
h. in a mutualistic/symbiotic relationship, the decrease in the population of one species would reduce cc for the other;
i. some species may evolve defence/resistance/adaptation mechanisms that decrease cc for predator/parasite/competitor species (respectively);
j. decline of an "ecosystem engineer species" (e.g. beavers, elephants) would decrease cc for many other species (in the same community); ["keystone" species would earn credit only in the context of MPs on predation and mutualism]
Do not credit responses that give no indication of impact on carrying capacity e.g. "predation" or "species preying on other species" does not indicate for which species cc is reduced, so gains no credit.
Allow [1 max] for reference to human population (considered MPc).
Credit may be gained through appropriate examples.