Question 1: Define a trophic level and describe its role within an ecosystem.

Answer: A trophic level is a position in a food chain occupied by organisms that share the same function in the food web, such as producers, consumers, or decomposers.

Question 2: Explain why only about 10% of energy is transferred from one trophic level to the next.

Answer: Most energy is lost as heat, used for metabolic activities, or remains in waste, so only about 10% of the energy is transferred to the next level.

Question 3: Which trophic level typically contains plants, and why are they crucial for food security?

Answer: Producers, such as plants, are at the first trophic level; they are crucial because they form the base of the food chain and produce the energy necessary for all other organisms.

Question 4: Calculate the amount of energy (in kcal) available to tertiary consumers if 1000 kcal is present at the producer level, assuming 10% energy transfer efficiency between each level.

Answer: Energy at tertiary level = 1000 kcal * 0.10 * 0.10 = 10 kcal

Question 5: Describe one potential consequence of a disruption at the primary producer level on food security.

Answer: A disruption at the producer level can lead to a collapse of the food chain, reducing food availability for all higher trophic levels and threatening food security.

Question 6: Multiple Choice: Which of the following is NOT a characteristic of decomposers?

Answer: They occupy the highest trophic level.

Question 7: Fill in the blank: In a food chain, the ______ is the organism that eats producers, and the ______ is the organism that eats consumers.

Answer: primary consumer, secondary consumer

Question 8: Identify two human activities that can disrupt trophic levels and negatively impact food security.

Answer: Deforestation and overfishing can disrupt trophic levels by removing key species, leading to imbalances and reduced food sources.

Question 9: Long Answer (6 marks): Discuss how changes in trophic levels due to climate change could affect global food security.

Answer: Climate change can alter habitats and affect species distribution at various trophic levels, leading to decreased populations of key producers and consumers. This disrupts energy flow, reduces crop yields and fisheries, and ultimately threatens food security worldwide.

Question 10: Explain how sustainable farming practices can help maintain trophic balance and improve food security.

Answer: Sustainable farming practices, such as crop rotation, integrated pest management, and conservation of natural habitats, help preserve biodiversity and trophic balance, ensuring a stable food supply.

Question 11: Describe an experiment to test the effect of fertilizer on plant growth, including variables and safety precautions.

Answer: An experiment can involve growing plants with different fertilizer concentrations. The independent variable is fertilizer amount; the dependent variable is plant growth. Control variables include soil type, water, and light. Safety precautions include wearing gloves when handling fertilizer and proper disposal of chemicals.