WJEC Biology Practice Exam 2025 - Free Biology Practice Questions and Study Guide

Biological magnification refers specifically to the process where certain substances, particularly toxins, become increasingly concentrated in the tissues of organisms as one moves up the food chain. This phenomenon occurs because these substances, such as heavy metals or certain pesticides, are often not easily broken down by biological processes, leading to higher concentrations in organisms that occupy higher trophic levels.

At lower trophic levels, organisms might absorb small amounts of these toxins through their diet or environment. However, as predators consume multiple prey organisms that contain these substances, the concentration of toxins accumulates in their bodies, resulting in significantly higher levels of these harmful substances in those at the top of the food chain. This can lead to various health issues and ecological consequences, demonstrating the interlinked nature of food webs and the impact of human activity on ecosystems.

The other options do not accurately define biological magnification as they pertain to different concepts in ecology, such as biodiversity, population dynamics, or nutrient cycles.