Ecology and Biodiversity: Food Chains, Biomes, National Parks & Conservation

Ecology and Biodiversity questions appear in both Science and General Knowledge sections of Kerala PSC papers. Expect 2-4 questions on national parks, food chains, conservation projects, and environmental concepts.

1. Basic Ecological Concepts

Term	Definition
Ecology	Study of interactions between organisms and their environment
Ecosystem	Biotic (living) + Abiotic (non-living) components interacting as a system
Habitat	Place where an organism lives
Niche	Functional role of an organism in its ecosystem
Biome	Large geographic area with similar climate, plants, and animals
Biosphere	Sum total of all ecosystems on Earth

2. Food Chain and Food Web

Trophic Level	Role	Examples
First (T1)	Producers (Autotrophs)	Plants, algae, phytoplankton
Second (T2)	Primary consumers (Herbivores)	Rabbit, deer, grasshopper
Third (T3)	Secondary consumers (Carnivores)	Frog, snake, small fish
Fourth (T4)	Tertiary consumers (Top predators)	Tiger, eagle, shark
Decomposers	Break down dead matter	Bacteria, fungi

Types of Food Chains

Type	Description	Example
Grazing food chain	Starts from green plants	Grass - Deer - Tiger
Detritus food chain	Starts from dead organic matter	Dead leaves - Earthworm - Bird

Food Web: Interconnected food chains in an ecosystem. More stable than a single food chain.

Energy Flow

• 10% Law (Lindeman, 1942): Only 10% of energy transfers from one trophic level to the next
• Energy flow is always unidirectional (producers to top consumers)
• Maximum energy at producer level; minimum at top consumer level

3. Ecological Pyramids

Type	What it Measures	Always Upright?
Pyramid of Number	Number of organisms at each level	Usually upright; inverted in tree ecosystem (1 tree supports many insects)
Pyramid of Biomass	Total dry weight at each level	Usually upright; inverted in ocean (phytoplankton biomass less than zooplankton at any instant)
Pyramid of Energy	Energy at each level	ALWAYS upright (10% law)

4. Biogeochemical Cycles

Cycle	Key Reservoir	Key Process
Carbon cycle	Atmosphere (CO2), ocean	Photosynthesis, respiration, combustion
Nitrogen cycle	Atmosphere (78% N2)	Nitrogen fixation (Rhizobium, Azotobacter), nitrification, denitrification
Water cycle	Oceans	Evaporation, condensation, precipitation
Oxygen cycle	Atmosphere	Photosynthesis (release), respiration (consumption)

5. Major Biomes of the World

Biome	Climate	Key Feature
Tropical Rainforest	Hot, heavy rainfall year-round	Maximum biodiversity; Amazon, Western Ghats
Tropical Deciduous Forest	Seasonal rainfall	Trees shed leaves in dry season; most of India
Desert	Very low rainfall	Xerophytic plants (cactus); Thar, Sahara
Grassland (Savanna/Steppe)	Moderate rain, seasonal	Grasses dominate; African Savanna
Tundra	Extremely cold, permafrost	Mosses, lichens; Arctic regions
Taiga (Boreal Forest)	Cold, short summers	Coniferous trees (pine, spruce); Siberia, Canada

6. Biodiversity

Term	Meaning
Biodiversity	Variety of life at genetic, species, and ecosystem levels
Alpha diversity	Diversity within a single habitat/community
Beta diversity	Diversity between habitats
Gamma diversity	Total diversity of a large region
Hotspot	Region with high endemism + high threat of habitat loss

Biodiversity Hotspots in India

Hotspot	Regions Covered
Western Ghats and Sri Lanka	Kerala, Karnataka, Tamil Nadu, Maharashtra, Goa (Western Ghats)
Eastern Himalayas	Northeast India, Nepal, Bhutan
Indo-Burma	Northeast India (parts), Myanmar
Sundaland	Nicobar Islands (part)

India has 4 of the world’s 36 biodiversity hotspots.

7. Endangered Species of India

Species	Status	Found In
Bengal Tiger	Endangered	Various tiger reserves
Asiatic Lion	Endangered	Gir Forest, Gujarat (ONLY habitat)
Indian Rhinoceros (One-horned)	Vulnerable	Kaziranga, Assam
Snow Leopard	Vulnerable	Himalayas (J&K, Ladakh, Himachal)
Red Panda	Endangered	Eastern Himalayas (Sikkim, Arunachal)
Nilgiri Tahr	Endangered	Western Ghats (Eravikulam, Kerala)
Lion-tailed Macaque	Endangered	Western Ghats (Silent Valley, Kerala)
Great Indian Bustard	Critically Endangered	Rajasthan, Gujarat
Gangetic Dolphin	Endangered	Ganga and tributaries

IUCN Red List Categories (in order)

1. Least Concern (LC)
2. Near Threatened (NT)
3. Vulnerable (VU)
4. Endangered (EN)
5. Critically Endangered (CR)
6. Extinct in the Wild (EW)
7. Extinct (EX)

8. National Parks of India (Key for PSC)

National Park	State	Famous For
Jim Corbett	Uttarakhand	First national park in India (1936); tigers
Kaziranga	Assam	One-horned rhinoceros; UNESCO World Heritage
Gir	Gujarat	Asiatic lion (only wild population)
Ranthambore	Rajasthan	Tigers; historical fort
Sundarbans	West Bengal	Royal Bengal Tiger; mangroves; UNESCO
Kanha	Madhya Pradesh	Tigers; inspiration for Kipling’s Jungle Book
Periyar	Kerala	Elephants, tigers; Thekkady lake
Silent Valley	Kerala	Lion-tailed macaque; tropical evergreen
Eravikulam	Kerala	Nilgiri Tahr
Bandipur	Karnataka	Tigers, elephants
Nagarhole (Rajiv Gandhi)	Karnataka	Tigers
Valley of Flowers	Uttarakhand	Alpine flowers; UNESCO World Heritage
Hemis	Ladakh	Snow leopard; largest national park in India

National Parks in Kerala

National Park	District	Key Species
Periyar	Idukki	Elephant, Tiger
Silent Valley	Palakkad	Lion-tailed Macaque
Eravikulam	Idukki	Nilgiri Tahr
Anamudi Shola	Idukki	Endangered flora
Mathikettan Shola	Idukki	Evergreen forests
Pampadum Shola	Idukki	Smallest NP in Kerala

9. Conservation Projects in India

Project	Year Started	Target Species
Project Tiger	1973	Bengal Tiger
Project Elephant	1992	Asian Elephant
Crocodile Conservation	1975	Gharial, Mugger, Saltwater Croc
Project Snow Leopard	2009	Snow Leopard
Indian Rhino Vision 2020	2005	One-horned Rhino
Project Hangul	1970	Kashmir Stag

Project Tiger — Key Facts

Feature	Detail
Launched by	Government of India, 1973
First Director	Kailash Sankhala
First Tiger Reserve	Jim Corbett, Uttarakhand
Governing body	National Tiger Conservation Authority (NTCA)
Total Tiger Reserves (approx.)	54 (as of 2023 census)
Tiger population (2022 census)	3,167
Tiger Reserve in Kerala	Periyar Tiger Reserve

10. Important Environmental Terms

Term	Meaning
Endemic species	Found only in a specific geographic area
Exotic/Alien species	Introduced from another region
Keystone species	Species whose removal causes collapse of ecosystem
Indicator species	Species that indicates health of an ecosystem
In-situ conservation	Conservation in natural habitat (national parks, sanctuaries, biosphere reserves)
Ex-situ conservation	Conservation outside natural habitat (zoos, botanical gardens, seed banks, gene banks)

11. Biosphere Reserves in India (Key ones)

Biosphere Reserve	State(s)	Key Feature
Nilgiri	Tamil Nadu, Kerala, Karnataka	First BR in India (1986)
Gulf of Mannar	Tamil Nadu	Marine biodiversity
Sundarbans	West Bengal	Mangrove; UNESCO
Nanda Devi	Uttarakhand	UNESCO
Pachmarhi	Madhya Pradesh	Sal forest
Agasthyamalai	Kerala, Tamil Nadu	Medicinal plants

12. PSC Exam Quick-Fire Facts

• Total National Parks in India: 106 (approximate, as of 2024)
• Total Wildlife Sanctuaries: 567+
• Total Biosphere Reserves: 18
• First national park: Jim Corbett (1936), originally named Hailey National Park
• Largest national park: Hemis (Ladakh)
• Smallest national park: South Button Island (Andaman and Nicobar)
• National animal: Bengal Tiger
• National bird: Indian Peacock
• National aquatic animal: Gangetic Dolphin
• World Environment Day: June 5
• World Wildlife Day: March 3
• Earth Day: April 22
• Ramsar Convention: Wetlands conservation (India has 80+ Ramsar sites)