Mppsc, Pre_Unit-7, (Updated 2024-2025), §Environment§

∆} Ecology:- "It is the scientific study of relationship of living organisms with each other & with their environment."

∆} "Oikos" :- Home or place to live in & "Logos" :- Study

"Study of home of nature"

∆} Environmental resources of energy flow & mineral cycling.

∆} Ecological principals or concepts are described in the classical texts of Vedic period as Vedas, Samhitas,  Brahmanas, Aranyaka & Upanishads.

∆} Surgical text - Sushrutasamhita.

∆} Information of land, water, air & season were indispensable for the life & that polluted air & water were injurious to health - Charak Samhita.

∆} Environment:- "Everything that surrounds or affect an organism during its lifetime, called environment."

{Total sum of living & non-living components}

∆} All organisms are dependent on other organisms & environment for - food, energy, water, oxygen, shelter & for other needs.

∆} It comprises of both - living (Biotic) & non-living (Abiotic) components.

∆} Environment is not static.

∆} Following two components of environment

∆} External environment of fish consist of abiotic components as Temperature, Water & Light, in which nutrients, oxygen & organic matter are dissolved.

∆} Biotic environment consists of Microscopic organisms like plankton.

∆} Internal environment of fish enclosed by outer surface body.

∆} Internal environment stable as compared to external environment.

∆} Injury, Illness & Excessive stress - upsets the internal environment.

∆} If a marine fish is transferred to a fresh water environment, it will not be able to survive.

∆} Main 6 levels of organisation in ecology

∆} Organism is an individual living being that has ability to act or function independently.

∆} Examples- Plant, Animal, Bacterium & Fungi.

∆} Group of organisms of same species called population.

∆} Population growth can be positive or negative.

∆} Main factors of population increase - Birth, Immigration.

∆} Main factors of  population decrease - Death, Emigration.

∆} Main limiting factors for the growth of  population are- Biotic & Abiotic components.

∆} Population of plants & animals seldom occur by themselves - "Community".

∆} In order to survive, individuals of any one species depend on individuals of different species.

∆} Major community- 

-Large size, well organised & independent.

- Depend only on sun's energy.

- Example: Tropical Evergreen in North-Eastern region of India.

∆} Minor community- 

- Not completely independent.

- Example: A mat of lichen on cow-dung 

∆} Structural & functional unit of Biosphere, consisting of community of living beings & physical environment - Ecosystem.

∆} Ecosystem includes - Animals, Plants, Fish, Birds, Trees, People, Water & Soil.

∆}When an ecosystem is healthy, means - All elements live in balance.

∆} Components of ecosystem - Biotic & Abiotic.

∆} Biotic components-

- Primary producers/Autotrophs/Self-nourishing 

- Consumers/Heterotrophs/Phagotrophs 

a) Micro(Saprophytic/Decomposer)

b) Macro

- Abiotic components-

a) Energy 

b) Rainfall 

c) Temperature 

d) Atmosphere 

e) Substratum 

∆} Ecosystem classified into two categories:-

A) Terrestrial Ecosystem- 

-Forest

-Grassland

-Desert

B) Aquatic Ecosystem-

-Fresh water

-Saline water

-Marine water

#) Ecotone:- 

-"Zone of junction".

- Ex. Mangrove forest represent an ecosystem between marine & terrestrial ecosystem.

#) Niche:-

- "Unique functional role or place of species."

- No two species have exact identical niche.

- Plays a crucial role in - "Conservation of organisms.

∆} Biome- "Terrestrial part of biospere is divisible into enormous region."

∆}No two biomes are alike.

∆}Climate determines the boundary of biome.

∆} Abundance of animals & plants are found.

∆}Most productive agricultural areas of the earth - Tropical Rain Forest .

∆} Part of the earth where life can exist - Biosphere .

∆} Highly integrating & interacting zone comprising of - Air, water & land.

∆}Life in biospere is abundant.

∆} Biosphere is absent in extreme of North & South poles, Highest Mountains & Deepest Oceans .