Question

By pitting two species of worms against each other at varying densities, researchers have determined that the zero growth isocline of species A is always above that of species B. This means that?

1) species A will always exclude species B.
2) species B will always exclude species A.
3) one species will exclude the other, depending on the initial conditions.
4) both species will coexist at a lower density than either would alone.

Answer 1

Species A will always exclude species B adhering to the competitive exclusion principle because it can sustain a higher population density, indicating it more effectively exploits shared resources, potentially driving species B to local extinction or forcing it to adapt or migrate.

Step-by-step explanation:

When researchers have determined that the zero growth isocline of species A is always above that of species B, species A will always exclude species B. This conclusion is supported by the competitive exclusion principle, which states that two species competing for the exact same resources cannot coexist in the same habitat.

Since species A's zero growth isocline is above species B's, this suggests that species A can sustain a higher population density than species B before growth rates become zero, indicating it is a more efficient exploiter of the available resources. Therefore, species B will be outcompeted and potentially driven to local extinction unless it can evolve different adaptations to exploit different resources or migrate to a new habitat with less competition.