Explain the capture-recapture method and calculate the population size of grasshoppers. Discuss the roles of decomposers and predators in an ecosystem.

1. a) The method used for population estimation involving capturing, marking, releasing, and then recapturing individuals is known as the capture-recapture method or Lincoln-Petersen index. b) To calculate the population of grasshoppers, we use the Lincoln-Petersen index formula: N = (M × C)/(R) Where: N = Estimated total population size M = Number of individuals captured and marked in the first sample = 36 C = Total number of individuals captured in the second sample = 45 R = Number of marked individuals recaptured in the second sample = 4 Step 1: Substitute the given values into the formula. N = (36 × 45)/(4) Step 2: Perform the multiplication in the numerator. N = (1620)/(4) Step 3: Perform the division. N = 405 The estimated population of grasshoppers is 405. 2. a) Decomposers are organisms that break down dead organic matter, such as dead plants and animals, and waste products. Their significance lies in recycling nutrients back into the ecosystem, making them available for producers. b) Predators are organisms that hunt and kill other organisms (prey) for food. Their significance in an ecosystem is to control prey populations, preventing overpopulation and maintaining the balance and health of the ecosystem. 3. a) A possible food chain from the given information is: Grass → Grasshopper → Bird b) The biomass of organisms decreases at each successive trophic level because energy is lost at each transfer. Only about 10% of the energy from one trophic level is transferred to the next; the remaining 90% is lost as heat during metabolic processes, used for life functions, or not consumed/assimilated. This reduction in available energy limits the total biomass that can be supported at higher trophic levels. 4. i) Autecology is the study of an individual organism or a single species in relation to its environment. It focuses on how a species interacts with its abiotic and biotic surroundings. ii) Biomass refers to the total mass of living organisms in a given area or ecosystem at a particular time. It is often expressed as dry weight per unit area or volume. Send me the next one 📸