Question 1: Define a food web and explain how it differs from a food chain.

Answer: A food web is a complex network of interconnected food chains showing the feeding relationships among various organisms in an ecosystem. Unlike a simple food chain, it illustrates multiple pathways for energy flow and nutrient cycling.

Question 2: List the three main types of organisms found in a typical food web and give an example of each.

Answer: Producers (e.g., grass), consumers (e.g., rabbits), decomposers (e.g., fungi).

Question 1: Explain how energy is transferred through a food web and why energy decreases at each trophic level.

Answer: Energy is transferred from one organism to another when an organism eats another; only about 10% of the energy is passed on at each trophic level due to energy lost as heat, respiration, and waste, which explains why energy decreases at each level.

Question 2: Multiple Choice: Which of the following best describes a decomposer's role in a food web?

Answer: C) They break down dead organic matter and recycle nutrients.

Question 1: Calculation: If a herbivore consumes 1000 kcal of plant material and only 10% of that energy is transferred to a carnivore that eats it, how much energy does the carnivore obtain?

Answer: Energy transferred = 1000 kcal × 0.10 = 100 kcal

Question 2: Scenario: In a pond ecosystem, the primary producers produce 5000 units of biomass annually. Secondary consumers are observed to have 50 units of biomass. Calculate the approximate biomass of primary consumers assuming a 10% transfer efficiency from producers to primary consumers.

Answer: Biomass of primary consumers = 5000 units × 0.10 = 500 units

Question 3: Data Analysis: A food web in a forest shows that if the population of top predators decreases, what potential effects could this have on the lower levels? Provide a brief explanation.

Answer: A decrease in top predators may lead to an increase in herbivore populations due to reduced predation, which can result in overgrazing of plants, habitat degradation, and possibly a disruption of the balance within the ecosystem.

Question 1: Describe a simple experiment to investigate the effect of removing a particular predator on the food web in a local ecosystem. Include the variables involved and safety precautions.

Answer: An experiment could involve temporarily excluding a predator species using barriers or traps, then monitoring changes in prey and plant populations over time. Variables include the presence/absence of the predator (independent), prey/population sizes (dependent), and environmental conditions (controlled). Safety precautions involve handling traps carefully and ensuring minimal disturbance to the ecosystem.

Question 1: Explain how knowledge of food webs can be used to manage fisheries sustainably.

Answer: Understanding food webs helps identify key species and energy flow patterns, enabling sustainable fishing practices that avoid overharvesting top predators or disrupting ecological balance, thus maintaining healthy fish populations and ecosystem stability.

Question 2: Multiple Choice: Which of the following human activities most directly disrupts natural food webs?

Answer: B) Pollution and habitat destruction