Unit 2: Ecosystems & Biodiversity

February 21, 2026

Semester 2
BP206T

Introduction to Ecosystems & Biodiversity

Unit 2 covers two of the most critical concepts in ecology: how ecosystems function (food chains, energy flow, nutrient cycles) and the value of Biodiversity. India is one of the 17 megadiverse nations. Understanding biodiversity is essential for future pharmacists, as plants and animals are sources of numerous life-saving drugs.

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Syllabus & Topics

  • 1Ecosystems: Definition, types (Forest, Grassland, Desert, Aquatic), and components.
  • 2Biotic components: Producers, Consumers, Decomposers.
  • 3Abiotic components: Temperature, Light, Water, Soil, Wind.
  • 4Energy Flow in Ecosystems: 10% law, Lindemann’s rule.
  • 5Food Chains and Food Webs: Types (Grazing, Detritus food chain).
  • 6Ecological Pyramids: Pyramid of Numbers, Biomass, and Energy.
  • 7Ecological Succession: Primary and Secondary succession.
  • 8Nutrient Cycling: Nitrogen Cycle, Carbon Cycle, Phosphorus Cycle.
  • 9Biodiversity: Definition and Types (Genetic, Species, Ecosystem diversity).
  • 10Biodiversity Hotspots: Definition and examples (Western Ghats, Eastern Himalayas in India).
  • 11Value of Biodiversity: Direct (food, medicines) and Indirect (ecosystem services).
  • 12Threats to Biodiversity: Habitat loss, Invasive species, Pollution, Over-exploitation.
  • 13Endangered and Endemic Species of India.
  • 14Conservation of Biodiversity: In-situ (National Parks, Sanctuaries, Biosphere Reserves) and Ex-situ (Seed Banks, Zoos).

Learning Objectives

Define Ecosystem: Describe the four structural components of an ecosystem.
Food Web: Draw a simple food web with at least 6 organisms.
10% Law: Explain why only 10% of energy is transferred between trophic levels.
Biodiversity Value: Give an example of a drug derived from a plant or animal.
Conservation Methods: Distinguish between In-situ and Ex-situ conservation.

Frequently Asked Questions (FAQs)

Q1. What is the “10% Law” of Energy Transfer?

Proposed by Lindemann (1942), the 10% law states that only about 10% of the energy stored at one trophic level is transferred to the next trophic level. The remaining 90% is lost as heat during metabolic processes.

Q2. What is a Biodiversity Hotspot?

A biodiversity hotspot is a region with exceptionally high species richness and significant threat from human activities (habitat loss).
To qualify, it must:

  • Have ≥ 1500 endemic plant species

  • Have lost more than 70% of its original habitat

Q3. Why is Biodiversity Important for Pharmacy?

Many life-saving drugs are derived from natural sources, such as:

  • Morphine – from Opium Poppy

  • Quinine – from Cinchona bark (antimalarial)

  • Penicillin – from Penicillium mold

  • Taxol (Paclitaxel) – from Pacific Yew tree (anticancer)

Biodiversity provides a valuable source for drug discovery and development.

Q4. What is the difference between In-situ and Ex-situ Conservation?

In-situ (on-site) conservation: Protects species in their natural habitats (e.g., National Parks, Wildlife Sanctuaries, Biosphere Reserves).
Ex-situ (off-site) conservation: Conserves species outside their natural habitats (e.g., Zoos, Seed Banks, Botanical Gardens).

Q5. What is Ecological Succession?

Ecological succession is the gradual change in species composition of a community over time.

  • Primary succession: Occurs on bare rock or newly formed substrate where no life existed before.

  • Secondary succession: Occurs in areas where a previous community was disturbed but soil remains.