Which concept explains that strong competition can lead to the local elimination of one species?

• A. Biological magnification
• B. Competitive exclusion
• C. Energy pyramid
• D. Trophic level

Answer: (B)

When two species try to use the same limited resources in the same area, one can outcompete the other and drive it to local extinction. This idea is known as the competitive exclusion principle: if the niches overlap too much for the same resources, stable coexistence isn’t possible, and one species will dominate the local community while the other is eliminated or pushed to use different resources.

This concept also ties into the idea of niches. A species’ fundamental niche is the full range of conditions and resources it could use, while its realized niche is what it actually uses given competition and other factors. When competition is strong, the realized niche can shrink for one species, leading to local exclusion, unless the species diverge in resource use (resource partitioning) to reduce overlap.

Biological magnification involves toxins becoming more concentrated up the food chain, not competition between species. An energy pyramid describes how energy is lost at each step of a food chain, not how species interact. A trophic level is simply the position an organism occupies in a food chain, which doesn’t by itself explain why one species might exclude another.