Ecosystem Concepts – Structure, Functions & Types

🌿 What is an Ecosystem?

An ecosystem is a system where living organisms (plants, animals, microbes) ➤ interact with non-living elements (air, water, soil).
🔹 Coined by A.G. Tansley in 1935
🔹 It's a functional unit of nature—where life and environment interact.

---

🏗️ Structure of Ecosystem

➡ An ecosystem has two main components:

🔹 1. Biotic Components (Living)

• Producers (Autotrophs) → 🌱 Plants that make food via photosynthesis

• Consumers (Heterotrophs)
  ➤ Primary (Herbivores) → Eat producers
  ➤ Secondary (Carnivores/Omnivores) → Eat herbivores
  ➤ Tertiary → Eat secondary consumers
  ➤ Quaternary (Top predators) → Eat tertiary, no predators themselves

• Decomposers → 🍄 Fungi & bacteria that break down dead material and recycle nutrients

🔹 2. Abiotic Components (Non-Living)

Includes:
☀️ Sunlight | 🌬️ Air | 💧 Water | 🪨 Soil | 🌡️ Temperature | 🧂 Minerals | Wind, pH, etc.

---

🌍 Types of Ecosystems

🔸 A. Terrestrial Ecosystems (Land-based)

• 🌳 Forest Ecosystem
  ➤ Trees + animals + microbes → interact with air, soil, etc.
  ➤ Help in temperature balance & carbon storage

• 🌾 Grassland Ecosystem
  ➤ Dominated by grasses and herbs
  ➤ Types: Temperate & Tropical (Savannas)

• ❄️ Tundra Ecosystem
  ➤ Cold, snow-covered, treeless areas
  ➤ Found in Arctic regions & mountain tops

• 🏜️ Desert Ecosystem
  ➤ Low rainfall, hot days & cold nights
  ➤ Sparse vegetation

🔸 B. Aquatic Ecosystems (Water-based)

• 💧 Freshwater → Rivers, lakes, ponds, streams (no salt)

• 🌊 Marine → Oceans & seas (high salt, diverse life)

---

🔁 Functions of an Ecosystem

✅ Supports life processes & ecosystem stability
✅ Cycles nutrients between living & non-living parts
✅ Maintains trophic level balance
✅ Flows energy from sun ➤ producers ➤ consumers ➤ decomposers
✅ Recycles minerals & organic matter

🔸 Functional Aspects:

• 🌱 Productivity → How much biomass is produced

• ⚡ Energy Flow → Sun ➤ Producers ➤ Consumers ➤ Decomposers

• 🪱 Decomposition → Break down of dead matter into nutrients

• 🔄 Nutrient Cycling → Reuse of essential elements (e.g. carbon, nitrogen)

---

🌾 Key Ecological Concepts

1️⃣ Food Chain

• Linear path of energy:
  ☀️ Sun ➤ 🌱 Plants ➤ 🐇 Herbivores ➤ 🐍 Carnivores ➤ 🦅 Top predators

• Decomposers break down leftovers → nutrients reused by plants

Example:
Grass ➤ Grasshopper ➤ Mouse ➤ Snake ➤ Eagle

2️⃣ Food Web

• A network of food chains

• Shows that most organisms eat & are eaten by more than one species

• More realistic than a single chain

3️⃣ Ecological Pyramids

• Shows number, biomass, or energy at each trophic level

• Base: Producers ➤ then Primary ➤ Secondary ➤ Tertiary ➤ (Quaternary if any)

Example Pyramid (by number):
Grass (1000) ➤ Grasshoppers (100) ➤ Mice (10) ➤ Snakes (5) ➤ Eagles (1)