VisionIAS
08:26
What is Environment?
The word Environment means ‘surroundings’ (environs). Therefore, the environment of an individual, object, or system includes all of the other entities – both living (biotic) and non-living (abiotic)-with which it is surrounded. In an environment.
What are the different types of environment?
Primarily, the environment can be categorised into two:
- Natural Environment: It includes all living and non-living things that occur naturally. For example, the environment in a forest surrounding an animal.
- Human-made/ Artificial Environment: It is the environment made by humans i.e. they don’t occur naturally.
What are the different components of an Environment?
The environment has two types of components: Biotic and Abiotic
What is an Ecosystem?
“Ecosystem” term was first coined by A.G. Tansely, in the year 1935. In simple terms, it is a community of living and non-living things that work together.
The living and non-living things continuously exchange materials and energy between them. It forms the structural and functional unit of the biosphere (sphere of life).
Ecosystem varies greatly in size. It can be as small as a pond or as large as a forest or sea.
Generalised Classification of Ecosystem:
Ecosystem is divided into two basic categories: Terrestrial and the Aquatic.
- Terrestrial: Forest, grassland and desert are some examples of terrestrial ecosystems.
- Aquatic: Pond, lake, wetland, river and estuary are some examples of aquatic ecosystems.
Ecosystems can be man-made too. Examples include an aquarium, crop field
Structure of an Ecosystem
The ecosystem consists of living (biotic) and non-living (abiotic) components. These components are linked with each other through nutrient cycling and energy flow. We will learn these processes in detail in the next discussion.
Now let us check the different components:
Autotrophs
They are the “Primary Producers”. They make their own food and do not “eat” others. Autotrophs can be of two types:
- Phototrophs: They derive their energy from the Sun – the primary source of energy on the planet. These are the green plants that make their own food by the process of photosynthesis.
- Chemotrophs: They obtain their energy from chemicals through a process called chemosynthesis and can make their own food. Example: Cyanobacteria
Heterotrophs
They are called “Consumers.” They take nourishment from others. They are not capable of making their own food. They can’t do photosynthesis. Hetero means “others”. They can again be classified into:
- Micro Consumers / Saprotrophs / Osmotrophs: These are organisms that feed on dead organic matter generated from plants and animals (‘sapro’=rotten or decaying). They are again of two types:
- Decomposers: These are those microorganisms such as bacteria and fungi that feed on and decompose other dead organic material.
- Detritus feeders: These are small animals which feed on partially decomposed organic material. They contribute to the break down of detritus (remains of dead organisms). Examples: earthworms, mites etc.
- Macro-consumers (Phagotrophs): These are consumers which feed on other living organisms for their source of energy. Phagotroph means nourishment by eating (phago=eating). They are of the following types:
- Primary consumers (Herbivores): They feed directly on plants. Example: Cow, goat, grasshopper etc.
- Secondary consumer (carnivore): They feed on primary consumers. They are the flesh-eating organisms. Example: fox, snakes, etc.
- Tertiary consumer (Top carnivore): They are the ones feeding on secondary consumers. Example: hawk, tiger, lion etc.
- Omnivores are those that eat both plants and animals. Some of us, (who are not vegetarians) are omnivores!!! Other examples include crow, rats etc.
Abiotic Components
- Climatic and physical factors -air, water, soil and sunlight; rainfall, temperature, humidity, soil texture and geomorphic conditions.
- Inorganic materials– Examples: carbon, nitrogen, sulfur, phosphorous, carbon-di-oxide, water, etc. These are involved in the cycling of materials in the ecosystems.
