Examkin

Question

Difficulty: HardEnergy Flow, Food Chains, and Ecological Pyramids

Consider the following organisms residing in a West African savanna ecosystem: Agama lizards, Star grass, Martial eagles, and Grasshoppers. Arrange these organisms in sequence from the trophic level containing the HIGHEST available energy to the trophic level containing the LOWEST available energy.

  1. 1Star grass
  2. 2Grasshoppers
  3. 3Agama lizards
  4. 4Martial eagles

Answer

Star grass → Grasshoppers → Agama lizards → Martial eagles
In accordance with the second law of thermodynamics, radiant energy fixed by primary producers (Star grass) is progressively lost as metabolic heat and waste as it flows through primary consumers (Grasshoppers), secondary consumers (Agama lizards), and tertiary consumers (Martial eagles). Consequently, available energy is always highest at the base of the food chain (trophic level 1) and lowest at the apex (trophic level 4).

Step-by-Step Solution

1
Identify the trophic role and position of each organism in the savanna food chain.
Star grass is a primary producer (trophic level 1); Grasshopper is a primary consumer/herbivore (trophic level 2); Agama lizard is a secondary consumer/carnivore (trophic level 3); Martial eagle is a tertiary consumer/apex predator (trophic level 4).
Trophic position dictates the direction of nutrient flow and relative energy content within an ecological community.
2
Apply Lindeman's efficiency rule (10% law) regarding energy transfer across trophic levels.
Energy decreases progressively from lower to higher trophic levels because approximately 90% of transferred energy is lost as heat via cellular respiration and unconsumed biomass at each link.
The second law of thermodynamics requires energy pyramids to remain upright, with energy concentration greatest at the base and lowest at the top.
3
Order the organisms from highest available energy to lowest available energy.
The correct sequence is Star grass (Producer, Level 1) → Grasshoppers (Primary Consumer, Level 2) → Agama lizards (Secondary Consumer, Level 3) → Martial eagles (Tertiary Consumer, Level 4).
Energy attenuation along a food chain mandates that producers hold the highest energy content while top predators hold the lowest.

Key Concept

Trophic energy attenuation and ecological pyramid hierarchy
Estimated Time:1m 30s
Rate this question

Topics

Energy Flow, Food Chains, and Ecological Pyramids

More questions from this topic