Amogh N P
✦ In loving memory of Amogh N P — Architect · Designer · Visionary ✦
A layered tropical forest ecosystem — producers, canopy and forest floor in one frame.
Unit I25ART203 · Environmental Studies in Architecture

Environmental Studies & Ecosystems

How nature works — energy, food webs and the slow march of succession.

≈ 30 min + study task

Every building sits inside a living system. Environmental studies is the science of those systems and of our impact on them — and for an architect it is the ground on which sustainable design is built. We begin with the ecosystem itself: how it is structured, how energy flows through it, and how it changes over time.

Learning objectives

By the end of this lesson, you will be able to — mapped to the course outcomes for Environmental Studies in Architecture:

1
CO1 · Understand

Explain what an ecosystem is and name its biotic and abiotic parts.

2
CO1 · Understand

Trace energy through a food chain and web, and state the 10% law.

3
CO1 · Analyse

Describe ecological succession from pioneer to climax community.

4
CO6 · Understand

Identify the main ecosystem types and a local example of each.

Structure & function

What an ecosystem is

An ecosystem is a community of living things — producers, consumers and decomposers — interacting with their non-living surroundings of sun, air, water and soil. Each part has a role, and the decomposers quietly recycle everything back to the start.[1, 6]

Structure of an ecosystem

An ecosystem is a community of living things (biotic) interacting with their non-living surroundings (abiotic — sun, air, water, soil). Its living members are producers (plants), consumers (animals) and decomposers (microbes) that recycle the dead.[1, 6]

How energy moves

Energy flow & the 10% law

Energy enters as sunlight and flows one way up the food chain — but only about 10% passes at each step, the rest lost as heat. That is why food chains are short and top predators few. Many chains interlink into a food web.[6]

Energy flow — the 10% law Producers — 100% Primary consumers — 10% Secondary — 1% Tertiary — 0.1% ~90% lost as heat each step a food chain ☀ sungrassdeertiger
DiagramAn energy pyramid showing about 10% of energy passing up each trophic level, with a food chain from sun to grass to deer to tiger
AspectGrazing food chainDetritus food chain
Starts fromenergy from the sundead organic matter
First linkproducer (green plant)detritivore / decomposer
Examplegrass → deer → tigerleaf litter → earthworm → bird
Dominant ingrasslands, open waterforest floors, soils
Energy at each step≈ 10% passes on≈ 10% passes on
Change over time

Succession & ecosystem types

Communities change through ecological succession — bare ground is colonised by pioneers, then grasses, shrubs and finally a stable climax community. The great ecosystem types — forest, grassland, desert and aquatic — each have their own climate, productivity and species.[1]

Ecological succession — bare rock to forest biomass & diversity time → bare rock lichen / moss grasses shrubs climax forest
DiagramEcological succession rising from bare rock through lichen, grasses and shrubs to a climax forest
An open grassland ecosystem, grazers on a sea of grass.
PhotoAn open grassland ecosystem, grazers on a sea of grass.Taspol Sawasdee · CC BY-SA 4.0 · via Wikimedia Commons
A freshwater wetland — a productive aquatic ecosystem of water, reeds and birds.
PhotoA freshwater wetland — a productive aquatic ecosystem of water, reeds and birds.Judgefloro · Public domain · via Wikimedia Commons
Apply it

Study task

Visit or recall a local ecosystem — a pond, a park, a patch of scrub. Draw its food web with at least two producers, two consumers and a decomposer, and mark where energy is lost as heat.

Check your understanding

Self-assessment

1. Roughly how much energy passes from one trophic level to the next?

2. Ecological succession ends in a relatively stable community called the —

3. Decomposers in an ecosystem are essential because they —

In a nutshell

Recap

An ecosystem = living community (producers, consumers, decomposers) + its non-living surroundings.
Energy flows one way from the sun; only ~10% transfers at each trophic level (the 10% law).
Ecological succession moves from pioneer to a stable climax community over time.
Ecosystem types: forest, grassland, desert (terrestrial) and freshwater & marine (aquatic).
The evidence

References & further reading

  1. [1]Anubha Kaushik & C.P. Kaushik, Perspectives in Environmental Studies. New Delhi: New Age International.
  2. [2]Daniel B. Botkin & Edward A. Keller, Environmental Science: Earth as a Living Planet. John Wiley & Sons.
  3. [3]R. Rajagopalan, Environmental Studies: From Crisis to Cure. Oxford University Press, 2016.
  4. [4]UGC / Bharati Vidyapeeth, A Textbook for Environmental Studies (the AICTE/UGC core module).
  5. [6]E.P. Odum & G.W. Barrett, Fundamentals of Ecology. Philadelphia: Saunders / Cengage.

Further reading

  • Anubha Kaushik & C.P. Kaushik, Perspectives in Environmental Studies — the standard Indian text.
  • E.P. Odum, Fundamentals of Ecology.
  • R. Rajagopalan, Environmental Studies: From Crisis to Cure.

Sources gathered and fact-checked June 2026. Published values vary by source, sample and method — treat as indicative and confirm against the cited standard before structural use.