Mains Paper II · 4 Environment & Ecology · APPSC Group 2
4.1 Ecology and ecosystems notes
8 notes, in reading order.
- 4.1.1Ecology: levels of organisation, habitat and niche
Ecology studies how organisms interact with each other and with their physical surroundings, at levels that run from a single organism up to the whole biosphere.
Advanced · 8 min · Read here - 4.1.2Ecosystem structure: biotic and abiotic components
An ecosystem is a functional unit of nature in which living organisms interact with each other and with their non-living surroundings, linked by energy flow and nutrient cycling.
Advanced · 7 min · Read here - 4.1.3Energy flow and productivity: food chains, food webs, trophic levels and decomposition
Energy enters an ecosystem as sunlight, is fixed by producers, and flows one way through trophic levels while most of it is lost as heat; decomposers return the nutrients locked in dead matter.
Advanced · 8 min · Read here - 4.1.4Ecological pyramids and the ten per cent law
Ecological pyramids show the number, biomass or energy at each trophic level; only the pyramid of energy is always upright, because only about a tenth of energy passes from one level to the next.
Advanced · 6 min · Read here - 4.1.5Ecological succession: primary, secondary and climax
Ecological succession is the gradual, fairly predictable change in the species of an area over time, until a stable climax community in balance with the climate is reached.
Advanced · 7 min · Read here - 4.1.6Population and community ecology: growth, interactions and keystone species
Populations grow by births and immigration and shrink by deaths and emigration, within limits set by resources, while species in a community interact in ways that can help, harm or leave each other unaffected.
Advanced · 9 min · Read here - 4.1.7Terrestrial biomes: ecology and adaptations
A biome is the largest recognisable assemblage of plants and animals on Earth, shaped mainly by temperature and rainfall, and its species show adaptations to those conditions.
Advanced · 8 min · Read here - 4.1.8Aquatic ecosystems: freshwater, estuarine, mangrove and marine
Aquatic ecosystems range from fresh water to salt water; estuaries, mangroves and coral reefs are among the most productive, and they protect coasts as well as feeding fisheries.
Advanced · 8 min · Read here
Practise Ecology and ecosystems. Questions with answers explained, from the same topics.
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