Chapter 13 · Question 10

What would happen if all organisms of one trophic level are removed from an ecosystem? Will the impact be the same at every trophic level? Explain with an example.

Q10

What would happen if all organisms of one trophic level are removed from an ecosystem? Will the impact be the same at every trophic level? Explain with an example.

Answer Revealed

Direct Answer:

If all organisms of one trophic level are removed, the entire ecosystem would be disrupted. The organisms at the level above would lose their food source and die, while organisms at the level below would experience unchecked population growth. The impact is NOT the same for all trophic levels. Removing producers (first trophic level) would be catastrophic — all consumers would die because there would be no source of food energy. Removing top carnivores would cause herbivore populations to explode, leading to overgrazing and eventual destruction of vegetation. For example, if all grasshoppers (primary consumers) were removed from a grassland, frogs (secondary consumers) would lose their food and die, while grass (producers) would grow unchecked initially.

Simple Explanation

If you remove one rung of a ladder, everything above falls and everything below overflows. If all producers (plants) disappeared, every animal would starve. If all top predators were removed, herbivores would multiply unchecked, eat all the plants, and the ecosystem would crash. Each level matters — but some removals cause faster damage than others. Removing producers is the worst because it cuts off the energy source for the entire food web.

Exam-Ready Structure

The removal of organisms from a trophic level is a critical ecological concept discussed in NCERT Class 10 Chapter 13 exercises (Questions 4 and 5), testing the student's understanding of ecosystem interdependence. 1. General consequence: If all organisms of one trophic level are killed, the food chain is broken. (a) The organisms of the trophic level immediately above (the predators of the removed group) will lose their food source. They will either starve and die, or migrate if possible. (b) The organisms of the trophic level immediately below (the prey of the removed group) will experience a population explosion because their predators are gone. This overpopulation may deplete their own food source (the level below them), eventually leading to a crash. 2. Is the impact the same for all trophic levels? No — the impact differs significantly depending on which trophic level is removed: (a) Removing producers (1st trophic level): This is the most catastrophic scenario. Producers are the base of every food chain, capturing solar energy and making it available to the rest of the ecosystem. Without producers, there is no food energy entering the ecosystem — all consumers, at every level, would eventually die. This is both immediate and total. (b) Removing primary consumers (2nd trophic level, herbivores): Secondary consumers (carnivores) lose their prey and would starve or decline sharply. Producers would multiply rapidly initially, but this unchecked growth could become unsustainable. (c) Removing secondary consumers (3rd trophic level): Primary consumers would multiply, leading to overgrazing and eventual depletion of producers. This could cause the entire ecosystem to collapse from the bottom up. (d) Removing top carnivores: The trophic level immediately below them would expand unchecked. These organisms would then over-consume their own food source, potentially leading to a cascading population crash down the chain. 3. Can any trophic level be removed without damage? No. The NCERT chapter summary states: 'The various components of an ecosystem are interdependent.' Every organism in an ecosystem has a role, and removing any trophic level breaks this interdependence. The ecosystem's stability — maintained by the food web — is lost when one level is eliminated. Even if the ecosystem does not collapse immediately, the balance is severely disturbed.

Key Points

Removing one trophic level breaks the food chain: level above loses food source (dies/declines), level below experiences population surge
Impact is NOT the same — removing producers is most catastrophic as it cuts off the energy source for the entire ecosystem
Removing top carnivores causes prey population explosion, leading to overgrazing and eventual ecosystem collapse
No trophic level can be removed without causing damage — all components of an ecosystem are interdependent
A food web provides some resilience, but the removal of an entire trophic level (not just one species) would cause severe disruption

Common Mistakes

Thinking removing top predators has no impact — it triggers a trophic cascade that can collapse the ecosystem
Suggesting that organisms 'just eat something else' — while a food web offers some alternatives, removal of ALL organisms in a trophic level removes an entire link that many species depend on

What would happen if all organisms of one trophic level are removed from an ecosystem? Will the impact be the same at every trophic level? Explain with an example.