Ontario Grade 9 Science Class Practice Exam

Bioaccumulation refers to the process where certain substances, particularly toxins like heavy metals or persistent organic pollutants, accumulate in an organism over time. As an organism consumes food, these substances can enter its body and become stored in its tissues. Because these toxins are often not easily broken down or excreted, they can increase in concentration within the organism, especially if the substances are present in the organisms it eats.

This process becomes particularly concerning when the affected organism is part of a food chain. As smaller organisms containing these toxins are consumed by larger predators, the concentration of the toxins can increase further, leading to higher levels of harmful substances accumulating in top predators. This cumulative effect can have serious implications for ecosystem health and human health, as these toxins can affect reproduction, growth, and even lead to serious diseases.

Other options describe different ecological processes unrelated to the accumulation of substances within organisms. For instance, obtaining nutrients focuses on essential substances for growth rather than harmful substances. Decomposition pertains to the breakdown of organic materials, while the reduction of biodiversity addresses environmental impacts but does not capture the specific process of toxin accumulation in organisms.