Examkin

Question

Difficulty: MediumEnergy Flow, Food Chains, and Ecological Pyramids

In an agricultural ecosystem, grasshoppers and palm-weevils feed directly on oil palm fronds, while praying mantises prey exclusively on grasshoppers. Agama lizards consume both grasshoppers and praying mantises. If a target pest control measure drastically reduces the grasshopper population, which of the following changes will occur in the energy flow of this food web?

  1. Energy transfer to praying mantises will decline, causing Agama lizards to obtain a larger proportion of their energy from alternative prey pathways.Answer
  2. B
    The energy pyramid of the ecosystem will invert because energy accumulates at the producer level without being consumed.
  3. C
    Praying mantises will adapt by absorbing metabolic heat from the environment to maintain their trophic position.
  4. D
    The total energy available at the primary producer level will increase to compensate for the lost primary consumers.

Answer

Energy transfer to praying mantises will decline, causing Agama lizards to obtain a larger proportion of their energy from alternative prey pathways.
Because energy flows unidirectionally through food chains, removing a key primary consumer (grasshoppers) reduces the energy available to its direct predator (praying mantises). Flexible higher-level predators (Agama lizards) must adapt by utilizing alternative trophic pathways to satisfy their metabolic energy requirements.

Step-by-Step Solution

1
Analyze the trophic positions in the food web.
Oil palm fronds are primary producers, grasshoppers and palm-weevils are primary consumers, praying mantises are secondary consumers, and Agama lizards act as both secondary and tertiary consumers.
Identifying trophic connections clarifies how energy moves through the different feeding links.
2
Determine the impact of reducing the grasshopper population on energy flow.
A reduction in grasshopper numbers decreases the energy transferred to praying mantises, which feed solely on grasshoppers.
Energy flow between trophic levels depends on biomass consumption.
3
Evaluate the response of higher trophic levels.
Agama lizards, having alternative prey (such as palm-weevils or other insects), will shift their predation effort to compensate for reduced energy input from the mantis/grasshopper line.
Food webs provide alternative pathways for energy flow when specific populations fluctuate.

Key Concept

Food Web Dynamics and Energy Redistribution
Rate this question

Topics

Energy Flow, Food Chains, and Ecological Pyramids

More questions from this topic