Name any two organisms which can occupy more than one trophic level in an ecosystem.

NCERT Exemplar · Q22

Q. Name any two organisms which can occupy more than one trophic level in an ecosystem.

Tripura TbseShort· 2mImportance★★★★★

51% · 33/65 Questions

🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Concept understanding — Ecological Pyramid

Picture a real pyramid -- wide at the base, narrowing all the way up to a single point at the top. Ecologists borrow exactly this shape to describe something that has nothing to do with stone: how numbers, weight (biomass), or energy are distributed across the feeding levels of a food chain. This visual model is called an ecological pyramid.

Every ecological pyramid works the same way. In your NCERT textbook (Class 12 Biology, Chapter 12, Ecosystem, section 12.5), the base always represents the producers -- the first trophic level -- and each successive tier above it represents the next trophic level up (herbivores, then primary carnivores, then secondary or top carnivores), with the apex representing the top-level consumer. Three distinct types are studied, because the same food-chain relationship can be measured in three different ways:

Pyramid of numbers -- plots the count of individual organisms at each trophic level. NCERT's own grassland example is dramatic: nearly 6 million producer plants are needed to support just three top-carnivores at the apex.
Pyramid of biomass -- plots the standing crop (usually expressed as dry weight, which is more accurate than fresh weight) of organisms at each level, rather than headcount.
Pyramid of energy -- plots the amount of energy present at each trophic level, measured per unit area, usually annually.

Important

In most ecosystems, all three pyramids come out upright -- producers are more numerous and have more biomass than herbivores, and herbivores more than carnivores -- because energy shrinks at every step up the food chain (the same 10 per cent law behind energy flow: only about 10 per cent of the energy at one trophic level is transferred to the next).

When a pyramid turns upside down -- numbers and biomass pyramids don't always come out upright, and NCERT points to genuine exceptions you're expected to reason through, not just memorise:

A single large tree can support so many feeding insects that a pyramid of numbers built around it is inverted right at the base -- one producer, many primary consumers.
The pyramid of biomass in the sea is commonly inverted: at any given moment the standing crop of tiny, fast-reproducing phytoplankton is small, yet it is turning over fast enough to support a much larger standing crop of the zooplankton feeding on it.

Note

The pyramid of energy is the one type that is never inverted -- it is always upright, in every ecosystem, without exception. Energy is lost as heat at every transfer between trophic levels (unlike nutrients, it is never recycled back), so the level below always has to hold more usable energy than the level feeding on it. …

Start your 14-day free trial to unlock the full solution →

Some organisms, like omnivores and certain aquatic species, feed at multiple trophic levels because their diet includes both producers and consumers, giving them a flexible position in the ecological pyramid.

The concept of an ecological pyramid — whether it is a pyramid of numbers, biomass, or energy — is built on the idea of trophic levels. Each level represents a step in the flow of energy, starting with producers at the base, then primary consumers (herbivores), secondary consumers (carnivores that eat herbivores), and so on up to top predators. In a strict, textbook pyramid, every organism is assigned to one fixed level. But nature is rarely that tidy.

Many organisms do not stick to a single diet. Their feeding habits change with age, season, or availability of food. This means they can occupy more than one trophic level, depending on what they eat at a given time. The NCERT textbook acknowledges this flexibility, and it is important to understand because it shows that ecological relationships are dynamic, not rigid.

Note

The trophic level of an organism is not a permanent label — it is defined by what it eats at that moment. A single species can shift levels across its life cycle or even within a single day.

Two clear examples from the NCERT syllabus are:

Human beings — We are classic omnivores. When we eat rice or wheat (plants), we function as primary consumers (herbivores). When we eat chicken or fish (animals that ate plants), we become secondary consumers. And if we eat a predator like a large fish that fed on smaller fish, we can even be a tertiary consumer. So a single human can occupy the second, third, or fourth trophic level depending on the meal. …

Start your 14-day free trial to unlock the full solution →

←Previous questionQ21 — Justify the pitcher plant as a producer.→Next questionQ23 — What is the ultimate source of energy for the ecosystems?

Q.Name any two organisms which can occupy more than one trophic level in an ecosystem.

🎓Unlock everything free for 14 days

Unlock everything free for 14 days