Describe biomagnification of a toxic chemical and relate it to the biomass pyramid
Biomagnification is the process by which certain toxic chemicals or substances increase in concentration as they move up the food chain. When this occurs, organisms at higher trophic levels have higher concentrations of the toxic chemical compared to those lower in the food chain.
To understand biomagnification better, let's relate it to the biomass pyramid. The biomass pyramid represents the relative amount of living organic matter, or biotic material, present at each trophic level in an ecosystem. Typically, the biomass decreases as you move up the pyramid, with the highest biomass at the bottom and the lowest biomass at the top.
Now, imagine that a toxic chemical is introduced into the environment, such as a pesticide or heavy metal. Initially, the concentration of this chemical may be relatively low in the environment. However, as organisms at the bottom of the food chain (such as plants) take in the contaminated water or soil, they accumulate small amounts of the toxic chemical in their body tissues.
The next trophic level, composed of herbivores or primary consumers, eats these contaminated plants, thereby ingesting a higher concentration of the toxic chemical. Since these primary consumers require more biomass to sustain themselves, they need to consume a larger quantity of the contaminated plants, resulting in further accumulation of the toxic chemical.
Now, when secondary consumers at the next trophic level, such as carnivores or predators, feed on these primary consumers, they accumulate an even higher concentration of the toxic chemical. This process continues as you move up the food chain, with each trophic level accumulating more of the toxic chemical than the previous one. Ultimately, the top predators, which have the highest position in the biomass pyramid, can accumulate significant amounts of the toxic chemical due to biomagnification.
This phenomenon occurs because a toxic chemical can take a longer time to be broken down or eliminated from an organism's body compared to the rate at which it is ingested. Hence, it becomes more concentrated with each trophic level, leading to higher potential risks and impacts on organisms at the top of the food chain.
In summary, biomagnification is the increasing concentration of a toxic chemical as it moves up the food chain, resulting in higher accumulations in organisms at higher trophic levels. This can be related to the biomass pyramid, where organisms at the top of the pyramid have the highest concentration of the toxic chemical due to their position and feeding habits in the ecosystem.