Question 1: Define 'trophic level' and describe its significance in a food chain.

Answer: A trophic level is a position an organism occupies in a food chain, indicating its feeding level, such as producer, consumer, or decomposer. It is significant because it determines energy transfer and food availability, impacting food security.

Question 2: Explain how energy is transferred between trophic levels and why only about 10% of energy is passed on.

Answer: Energy is transferred from one trophic level to the next primarily through consumption. Only about 10% of energy is passed on because the rest is lost as heat, used for metabolic processes, or remains in parts of the organism that are not consumed. This efficiency affects the number of trophic levels sustainable in an ecosystem and food security.

Question 1: A plant produces 1000 kcal of energy. If a herbivore consumes it and only 10% of the energy is transferred to the herbivore, how much energy does the herbivore obtain? (Show calculation with units.)

Answer: Energy obtained by herbivore = 1000 kcal x 0.10 = 100 kcal

Question 2: A secondary consumer eats 50 kcal of energy from a primary consumer. What percentage of the original energy (from the producer) is this, assuming 10% transfer efficiency at each level? Show your calculations.

Answer: Original energy from producer = 50 kcal / 0.10 / 0.10 = 5000 kcal; Percentage = (50 kcal / 5000 kcal) x 100 = 1%

Question 1: Describe an experiment to test the effect of fertilizer on plant growth, including variables to control and safety precautions.

Answer: An experiment can involve planting identical seeds in pots with soil, applying different fertilizer types or amounts, and measuring growth over time. Controlled variables include seed type, pot size, and watering schedule. Safety precautions include wearing gloves when handling fertilizers, avoiding inhalation of dust, and proper disposal of chemical residues.

Question 2: Identify the independent variable, dependent variable, and one controlled variable in a study measuring how different feeding strategies affect poultry growth.

Answer: Independent variable: Feeding strategy; Dependent variable: Poultry growth; Controlled variable: Feed type (other than the variable being tested), environment conditions, age of poultry.

Question 1: In a farm, it was observed that only 8% of the energy from crops reaches the top predators. Discuss how this inefficiency might affect the sustainability of predator populations and overall food security.

Answer: The low energy transfer efficiency limits the amount of energy available to top predators, potentially reducing their population size. This inefficiency can lead to imbalances in the ecosystem and threaten food security by decreasing biodiversity and the stability of food sources for humans dependent on top predators.

Question 1: Explain why increasing the number of trophic levels in an ecosystem can pose challenges to food security.

Answer: Adding more trophic levels reduces the energy available at each level due to energy loss, which can lead to fewer organisms at higher levels and potentially disrupt food production, thereby posing challenges to maintaining food security.

Question 2: Describe how sustainable farming practices can improve food security by influencing trophic levels.

Answer: Sustainable farming practices, such as crop rotation, organic farming, and integrated pest management, can enhance soil health and biodiversity, supporting higher crop yields and healthier ecosystems. This maintains balanced trophic levels and ensures a stable food supply, thereby improving food security.

Question 1: How can understanding trophic levels assist in developing sustainable fisheries?

Answer: Understanding trophic levels helps in managing fish populations by preventing overfishing of top predators and maintaining balanced ecosystems, ensuring long-term productivity and food security.

Question 2: Discuss the role of trophic level analysis in designing efficient food chains for agricultural production.

Answer: Trophic level analysis helps identify the most efficient pathways for energy transfer, enabling farmers to optimize crop and livestock choices. It supports designing food chains that maximize food output with minimal energy loss, enhancing sustainability and food security.