Final answer:
Parasites and pathogens can affect community composition by causing disease and altering species interactions. Infected hosts may experience reduced fitness and reproduction, impacting the abundance and distribution of species. Pathogens can cause disease outbreaks, leading to changes in species composition.
Step-by-step explanation:
Parasites and pathogens can affect community composition by causing disease and altering the interactions between species. Parasites harm the host organism, while pathogens specifically cause disease.
These harmful effects can lead to changes in the abundance and distribution of species within a community, potentially leading to shifts in community structure and composition.
For example, let's consider a parasite that infects a species within a community. The infected host may experience reduced fitness and reproduction, which can impact the overall abundance and distribution of the host species.
This, in turn, can affect other species within the community that interact with the infected host, such as predators or prey.
The presence of a pathogen, on the other hand, can lead to disease outbreaks within a population or community, causing higher mortality rates and potentially leading to changes in species composition as some species may be more susceptible than others.