Question

In laboratory experiments, two species of the protist Paramecium (species $1$ and $2$) were grown alone and in the presence of the other species. The following graphs show growth of species $1$ and species $2$, both alone and when in mixed culture with the other species.

Which of the following conclusions can be drawn from the graphs ?

• A. Competitive exclusion occurred in these experiments
• B. Both species are affected by interspecific competition but species $1$ is affected less
• C. Both species are affected by interspecific competition but species $2$ is affected less
• D. Both species are affected equally by interspecific competition

Answer 1

Answer: (C)

When species $1$ was kept with species $2$, its number of individuals fell drastically while when species $2$ was kept with species $1$, its number of individuals was not much affected. Hence, both species are affected by inter-specific competition but species $2$ is less affected.