Question 1: Define a trophic level in an ecological food chain.

Answer: A trophic level is a position an organism occupies in a food chain, based on how it obtains energy, such as producer, primary consumer, secondary consumer, etc.

Question 2: Explain how energy transfer occurs between trophic levels and why energy decreases as it moves up the food chain.

Answer: Energy is transferred from one trophic level to the next primarily through consumption. However, only about 10% of energy is passed on, while the rest is lost as heat, respiration, or waste. This decrease limits the number of higher trophic levels and affects food security.

Question 3: What is meant by 'food security' in the context of ecology?

Answer: Food security refers to the availability, access, and sustainable production of sufficient, safe, and nutritious food for all people at all times.

Question 1: If a primary producer has an energy content of 1000 kcal, how much energy would be available to a secondary consumer assuming 10% transfer efficiency per trophic level?

Answer: 10 kcal. Calculation: Energy at secondary consumer = 1000 kcal * 0.10 (primary to herbivore) * 0.10 (herbivore to secondary consumer) = 1000 * 0.01 = 10 kcal.

Question 2: A farmer observes that their chicken feed contains 500 grams of protein. If 20% of the protein is retained when chickens eat and grow, how much protein is stored in the chickens after feeding?

Answer: 100 grams. Calculation: 500 grams * 0.20 = 100 grams.

Question 1: Design a simple experiment to test the effect of different fertilizer levels on plant growth, including the variables to be controlled and measured.

Answer: Controlled variables include soil type, amount of water, and sunlight. The independent variable is fertilizer level, and the dependent variable is plant height or biomass. The experiment should include multiple test plots with varying fertilizer amounts and consistent conditions for other factors.

Question 2: List two safety precautions students should follow when conducting experiments involving chemicals or biological materials.

Answer: Wear safety goggles and gloves to prevent chemical or biological exposure.

Question 1: In a hypothetical ecosystem, the biomass of producers is 1000 kg, herbivores is 100 kg, and carnivores is 10 kg. Explain what this indicates about energy transfer and potential food security concerns.

Answer: The significant decrease in biomass at each higher trophic level indicates energy loss and limited capacity to support larger populations of top predators. This energy transfer inefficiency can threaten food security by reducing the stability and productivity of the ecosystem.

Question 2: A community relies on a fish population that has declined by 40% over five years. Discuss how trophic level disruptions could impact local food security.

Answer: Disruptions at the trophic level, such as a decline in fish populations, can reduce food availability for humans and other predators. This can lead to nutritional deficiencies, economic losses, and increased pressure on alternative food sources, thereby threatening overall food security.

Question 1: Describe how sustainable fishing practices can help maintain trophic level balance and improve food security.

Answer: Sustainable fishing limits the catch of certain species, allowing populations to recover and maintaining the balance of trophic levels. This ensures a steady food supply and supports ecological stability, thereby enhancing food security.

Question 2: Explain how advances in agricultural technology can influence trophic levels and contribute to food security.

Answer: Technologies such as precision farming, genetically modified crops, and sustainable fertilizers increase crop yields and resource efficiency. This supports higher primary productivity, stabilizes trophic levels, and ensures sufficient food supply to meet demand.