Problem 4 - Campbell Biology

Question

Application/Analysis Which of the following is a consequence of biological magnification? (A) Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers. (B) Populations of top-level predators are generally smaller than populations of primary consumers. (C) The biomass of producers in an ecosystem is generally higher than the biomass of primary consumers. (D) Only a small portion of the energy captured by producers is transferred to consumers.

Step-by-Step Solution

Answer

Option (A) describes the risk of toxic chemicals to top-level predators.

Step 1 - Understand Biological Magnification

Biological magnification, also known as biomagnification, refers to the process by which the concentration of toxic substances increases in each successive link in the food chain. These substances are often fat-soluble and are stored in the fatty tissues of organisms, becoming more concentrated as they move up the food chain.

Step 2 - Identify the Impact on Food Chain Levels

Since these toxic chemicals become more concentrated at higher trophic levels, species that are top-level predators are at a greater risk because they consume multiple lower trophic level organisms, each contributing to the accumulation of toxins.

Step 3 - Evaluate the Answer Choices

Analyze each answer option to see which one correctly describes a consequence of biological magnification: (A) Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers. (B) Populations of top-level predators are generally smaller than populations of primary consumers. (C) The biomass of producers in an ecosystem is generally higher than the biomass of primary consumers. (D) Only a small portion of the energy captured by producers is transferred to consumers. Option (A) directly mentions the risk posed by toxic chemicals to top-level predators, which is a direct consequence of biomagnification. The other options do not directly address the amplification of toxins.

Step 4 - Select the Correct Answer

From the analysis, it is clear that Option (A) correctly describes the consequence of biological magnification.

Key Concepts

toxic chemicals

Toxic chemicals refer to substances that are harmful to living organisms. They can enter the environment through various means, such as industrial processes, agricultural runoff, and household waste. Once released, these chemicals can persist in the environment for a long time.

• Common examples include pesticides like DDT, heavy metals like mercury, and industrial chemicals like PCBs.
• These chemicals can be absorbed by plants and animals, often entering the food chain.

These substances are particularly dangerous because they are often fat-soluble, meaning they are stored in the fatty tissues of organisms. Since they don't easily break down, they accumulate over time, making their way up the food chain through a process called biomagnification.

trophic levels

Trophic levels describe the positions of organisms within a food chain. Each level represents a step in the flow of energy and nutrients through an ecosystem.

• Producers: These are usually plants and algae that create their own food through photosynthesis.
• Primary consumers: These are herbivores that consume producers.
• Secondary consumers: These are carnivores that eat primary consumers.
• Top-level predators: These are animals at the top of the food chain and have no natural predators.

As you go up each trophic level, the concentration of toxic chemicals increases due to biomagnification. This means that top-level predators, such as eagles, sharks, and humans, are at a higher risk of toxic exposure than organisms at lower trophic levels.

biomagnification

Biomagnification, also known as biological magnification, is the process by which the concentration of toxic chemicals increases as they move up the food chain.
This occurs because toxic chemicals are not easily broken down, and they accumulate in the fatty tissue of organisms. When a predator eats prey, it also ingests all of the toxins stored in that prey. Over time, this process leads to very high concentrations of toxic substances in top-level predators.

• For example, a small fish might eat plankton that contains toxins. A larger fish eats many small fish, accumulating more toxins. A bird that eats the larger fish ingests an even greater concentration of these toxins.
• This explains why top-level predators are most at risk from toxic chemicals in the environment.

Knowing how biomagnification works helps us understand why controlling pollution at the source is crucial for protecting wildlife and human health.