Common intermediate Environment Ecology Space ISRO Solar System
Environment, Ecology, and Space Science for Kerala PSC
Ecosystem basics, pollution, biodiversity, conservation, ISRO missions, solar system, and space facts. Based on NCERT Class 8-10 Science and current affairs.
Published: 14 Apr 2026 Relevant for: LDC, Last Grade Servants, Graduate Level Prelims, Secretariat Assistant
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Environment and Space together account for 3-6 questions per Kerala PSC paper. Environment questions test pollution, conservation, and ecology. Space questions test ISRO achievements and solar system basics.
ENVIRONMENT AND ECOLOGY
Ecosystem Basics (NCERT Class 10, Chapter 15)
| Term | Definition |
|---|---|
| Ecosystem | A community of living organisms interacting with their physical environment |
| Biotic factors | Living components — plants, animals, microorganisms |
| Abiotic factors | Non-living components — sunlight, temperature, water, soil |
| Food chain | Linear sequence of organisms where each is eaten by the next |
| Food web | Interconnected food chains in an ecosystem |
| Trophic level | Position in the food chain (producer → primary consumer → secondary → tertiary) |
| 10% Law | Only ~10% of energy transfers to the next trophic level (Lindeman’s Law) |
Trophic Levels
| Level | Organisms | Examples |
|---|---|---|
| Producers (1st) | Autotrophs — make own food | Plants, algae, phytoplankton |
| Primary consumers (2nd) | Herbivores — eat plants | Rabbit, deer, grasshopper |
| Secondary consumers (3rd) | Carnivores — eat herbivores | Frog, snake, small fish |
| Tertiary consumers (4th) | Top predators | Eagle, tiger, shark |
| Decomposers | Break down dead matter | Bacteria, fungi |
PSC fact: The 10% Law (Lindeman’s Rule) states that only about 10% of energy from one trophic level is available to the next level. This is why food chains rarely have more than 4-5 levels.
Types of Pollution
Air Pollution
| Pollutant | Source | Effect |
|---|---|---|
| CO₂ | Fossil fuels, deforestation | Greenhouse effect → global warming |
| CO (Carbon Monoxide) | Incomplete combustion | Poisonous; binds to haemoglobin |
| SO₂ (Sulphur Dioxide) | Coal burning, industrial emissions | Acid rain |
| NO₂ (Nitrogen Dioxide) | Vehicle emissions | Smog, respiratory problems |
| CFCs | Refrigerators, AC, aerosols | Ozone layer depletion |
| SPM (Suspended Particulate Matter) | Construction, vehicle exhaust | Lung diseases |
Water Pollution
| Source | Pollutant | Effect |
|---|---|---|
| Industrial waste | Heavy metals, chemicals | Toxic to aquatic life |
| Sewage | Organic waste, pathogens | Eutrophication, disease |
| Agriculture | Pesticides, fertilizers | Algal bloom, dead zones |
| Oil spills | Petroleum | Kills marine life |
Soil Pollution
| Source | Cause |
|---|---|
| Pesticides and fertilizers | Chemical contamination |
| Industrial waste | Heavy metal accumulation |
| Plastic waste | Non-biodegradable pollution |
| Deforestation | Soil erosion, nutrient loss |
Important Environmental Concepts
| Concept | Definition |
|---|---|
| Greenhouse Effect | Trapping of heat by greenhouse gases (CO₂, CH₄, N₂O) → global warming |
| Ozone Layer | O₃ layer in stratosphere; absorbs UV radiation; depleted by CFCs |
| Ozone Hole | Thinning over Antarctica; Montreal Protocol (1987) banned CFCs |
| Acid Rain | Rain with pH below 5.6; caused by SO₂ and NO₂ |
| Eutrophication | Excessive algae growth in water due to nutrient pollution |
| Biomagnification | Concentration of toxins increasing up the food chain |
| Biodegradable | Waste that decomposes naturally (paper, food waste) |
| Non-biodegradable | Waste that doesn’t decompose (plastic, glass, metals) |
| Carbon footprint | Total CO₂ emissions caused by an individual/organization |
PSC must-know:
- Greenhouse gases: CO₂, Methane (CH₄), Nitrous Oxide (N₂O), CFCs
- Ozone depleted by: CFCs
- Montreal Protocol: 1987 (banned CFCs)
- Kyoto Protocol: 1997 (greenhouse gas reduction targets)
- Paris Agreement: 2015 (limit warming to 1.5-2°C above pre-industrial)
Environmental Laws and Agreements
| Law/Agreement | Year | Purpose |
|---|---|---|
| Wildlife Protection Act | 1972 | Protects wild animals and plants; established national parks and sanctuaries |
| Water (Prevention of Pollution) Act | 1974 | Controls water pollution |
| Forest Conservation Act | 1980 | Restricts diversion of forest land |
| Air (Prevention of Pollution) Act | 1981 | Controls air pollution |
| Environment Protection Act | 1986 | Umbrella legislation for environmental protection |
| National Green Tribunal (NGT) | 2010 | Judicial body for environmental disputes |
| Montreal Protocol | 1987 | International treaty to phase out ozone-depleting substances |
| Kyoto Protocol | 1997 | Binding emission reduction targets for developed countries |
| Paris Agreement | 2015 | Global commitment to limit temperature rise; India ratified 2016 |
Biodiversity and Conservation
| Term | Meaning |
|---|---|
| Biodiversity | Variety of life forms in an area |
| Endemic species | Species found only in a specific region |
| Endangered species | Species at risk of extinction |
| Extinct species | No longer exists (e.g., Dodo, Mammoth) |
| In-situ conservation | Protecting species in their natural habitat (national parks, sanctuaries) |
| Ex-situ conservation | Protecting species outside their habitat (zoos, botanical gardens, seed banks) |
| Biodiversity hotspot | Area with high endemic species and significant habitat loss |
India’s Biodiversity Hotspots (4):
- Western Ghats (including Kerala)
- Eastern Himalayas
- Indo-Burma (NE India)
- Sundaland (Nicobar Islands)
PSC fact: India has 4 biodiversity hotspots. The Western Ghats (which includes Kerala) is one of them. India is one of the 17 “megadiversity” countries in the world.
National Parks and Tiger Reserves
| National Park | State | Known for |
|---|---|---|
| Jim Corbett | Uttarakhand | First national park in India (1936); Project Tiger |
| Kaziranga | Assam | One-horned Indian Rhinoceros |
| Gir | Gujarat | Asiatic Lion (only place in the world) |
| Ranthambore | Rajasthan | Tiger; former hunting ground of Jaipur royals |
| Sundarbans | West Bengal | Royal Bengal Tiger; largest mangrove forest |
| Periyar | Kerala | Indian Elephant; Tiger Reserve |
| Silent Valley | Kerala | Lion-tailed Macaque; tropical evergreen forest |
| Eravikulam | Kerala | Nilgiri Tahr; Neelakurinji |
Project Tiger: Launched in 1973 to protect the tiger. Jim Corbett National Park was the first Project Tiger reserve. India now has 50+ tiger reserves.
SPACE SCIENCE
Solar System
| Object | Key facts |
|---|---|
| Sun | Star at centre; mainly hydrogen and helium; age ~4.6 billion years |
| Mercury | Smallest planet; closest to Sun; no atmosphere |
| Venus | Hottest planet (thick CO₂ atmosphere); “Morning/Evening Star”; rotates backwards |
| Earth | Only planet with life; 71% water; one moon |
| Mars | ”Red Planet” (iron oxide surface); two moons (Phobos, Deimos) |
| Jupiter | Largest planet; Great Red Spot (storm); most moons historically; gas giant |
| Saturn | Most moons (146+); famous rings; least dense (would float on water) |
| Uranus | Rotates on its side; blue-green colour; ice giant |
| Neptune | Farthest planet; strongest winds; blue colour |
PSC Solar System facts:
- Order from Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune (My Very Educated Mother Just Served Us Noodles)
- Smallest: Mercury
- Largest: Jupiter
- Hottest: Venus (not Mercury — Venus has greenhouse effect)
- Red Planet: Mars
- Planet with rings: Saturn (most famous, but Jupiter, Uranus, Neptune also have faint rings)
- Pluto: reclassified as dwarf planet in 2006 by IAU
ISRO (Indian Space Research Organisation)
| Fact | Detail |
|---|---|
| Founded | 1969 |
| Founder | Dr. Vikram Sarabhai (“Father of Indian Space Programme”) |
| HQ | Bangalore |
| Launch centre | Sriharikota (Satish Dhawan Space Centre, Andhra Pradesh) |
| VSSC | Vikram Sarabhai Space Centre, Thiruvananthapuram (rocket development) |
| Motto | ”Space technology in the service of mankind” |
Key ISRO Missions
| Mission | Year | Significance |
|---|---|---|
| Aryabhata | 1975 | First Indian satellite (launched by USSR) |
| Rohini | 1980 | First satellite launched by Indian rocket (SLV-3) |
| INSAT-1A | 1982 | First Indian communication satellite |
| IRS-1A | 1988 | First Indian remote sensing satellite |
| Chandrayaan-1 | 2008 | First Indian lunar mission; discovered water on Moon |
| Mangalyaan (MOM) | 2013-14 | First Indian Mars mission; India = first country to succeed on first attempt |
| Chandrayaan-2 | 2019 | Orbiter successful; lander (Vikram) crashed |
| Chandrayaan-3 | 2023 | Successful soft landing on Moon’s south pole (23 Aug 2023); India = 4th country to land on Moon |
| Aditya-L1 | 2023 | India’s first solar observatory mission |
| Gaganyaan | Upcoming | India’s first crewed space mission |
PSC ISRO favourites:
- Father of Indian space: Vikram Sarabhai
- First satellite: Aryabhata (1975)
- First Mars mission success: Mangalyaan (2014) — cheapest Mars mission ever (~₹450 crore)
- Chandrayaan-3 landing: 23 August 2023 — south pole of Moon
- ISRO HQ: Bangalore
- Launch centre: Sriharikota
- Gaganyaan: first Indian crewed mission (upcoming)
Important Space Facts
| Fact | Answer |
|---|---|
| First man in space | Yuri Gagarin (USSR, 12 April 1961) |
| First woman in space | Valentina Tereshkova (USSR, 1963) |
| First man on Moon | Neil Armstrong (USA, 20 July 1969, Apollo 11) |
| First satellite in space | Sputnik 1 (USSR, 4 October 1957) |
| First animal in space | Laika (dog, USSR, 1957) |
| First Indian in space | Rakesh Sharma (1984, aboard Soviet Soyuz T-11) |
| First Indian-origin woman in space | Kalpana Chawla (1997, Columbia; died in 2003 Columbia disaster) |
| Largest planet | Jupiter |
| Planet closest to Sun | Mercury |
| Nearest star to Earth | Sun (next nearest: Proxima Centauri) |
| Light year is a unit of | Distance (not time) |
| 1 Light year | ~9.46 trillion km |
| International Space Station (ISS) | Multinational; orbits at ~408 km altitude |
Quick Revision — 25 Environment & Space Facts
- Greenhouse gases: CO₂, CH₄, N₂O, CFCs
- Ozone depleted by: CFCs
- Montreal Protocol: 1987
- Paris Agreement: 2015
- India’s biodiversity hotspots: 4 (Western Ghats, Eastern Himalayas, Indo-Burma, Sundaland)
- First national park in India: Jim Corbett (1936)
- Project Tiger started: 1973
- Asiatic Lion found only at: Gir, Gujarat
- One-horned rhino at: Kaziranga, Assam
- 10% Law: energy transfer between trophic levels
- Biomagnification: toxin concentration increases up food chain
- ISRO founded: 1969
- ISRO founder: Vikram Sarabhai
- ISRO HQ: Bangalore
- First Indian satellite: Aryabhata (1975)
- Mangalyaan: 2014 (first attempt Mars success)
- Chandrayaan-3: 23 August 2023 (Moon south pole)
- First man in space: Yuri Gagarin (1961)
- First on Moon: Neil Armstrong (1969)
- First Indian in space: Rakesh Sharma (1984)
- Smallest planet: Mercury
- Largest planet: Jupiter
- Hottest planet: Venus
- Red Planet: Mars
- Light year measures: Distance
Notes based on NCERT Class 8 Science (Ch. 18), Class 10 Science (Ch. 15-16), and ISRO official records. Updated April 2026.
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