- 1 Environment
- 2 Ecosystem and its components
- 3 Types of Ecosystems
- 4 Components of Ecosystem
- 5 Example of an Ecosystem
Environment includes everything around the organism, i.e. both non-living (abiotic) and living(biotic) components.
The abiotic components are the physical factors such as climatic factors (e.g., temperature, light, wind, humidity, precipitation, water etc.) and edaphic factors (e.g., soil texture, substratum, topography, background, minerals, pH etc.)
The biotic components include all kinds of living organisms with which the organism interacts.
This interdependent interaction among organisms as well as with the abiotic components maintains a balance in nature.
Increase in human population and great advancement in technology damaged the balanced and healthy environment.
Ecosystem and its components
All living organisms (microorganisms, algae, fungi, plants, animals and human beings) regularly interact with each other and with the non-living (abiotic) physical surroundings to maintain a balance in nature.
An ecosystem may be defined as a structural and functional unit of the biosphere comprising living organisms and their non- living environment that interact by means of food chains and chemical cycles resulting in energy-flow, biotic diversity and material cycling to form a stable, self-supporting system.
Types of Ecosystems
In the biosphere, ecosystems may be classified on the basis of their nature, duration and size.
On the basis of nature, ecosystems may be classified as:
1. Natural ecosystems
2. Artificial ecosystems
(1) Natural ecosystems: These ecosystems operate in the nature by themselves without any human interference. Examples of natural ecosystems are a pond, a lake, a meadow, a desert, a grassland, a forest, an ocean etc.
(2) Artificial ecosystems: These are maintained by man and hence are also termed man-made or man-engineered ecosystems. In these ecosystems, man maintains/disturbs the natural balance by the addition of energy and planned manipulations. Examples of artificial ecosystems are croplands, orchards, gardens, aquarium etc.
On the basis of duration, ecosystems may be classified as :
1. Temporary ecosystems
2. Permanent ecosystems
(1) Temporary ecosystems: These are short-lived ecosystems which may be natural or man-made.
Examples : Rainfed pond and laboratory culture of protozoans.
(2) Permanent ecosystems: These are self-supporting natural ecosystems that maintain themselves for relatively long duration.
Examples : a lake, a forest, a desert etc.
On the basis of size, ecosystems may be classified as:
1. Small ecosystems
2. Large ecosystems
(1) Small ecosystems: Small-sized ecosystems are also termed microecosystems.
Example : a flowerpot, water in a dish, a site under a stone etc.
(2) Large ecosystems: Very large-sized ecosystems are also termed macro-ecosystems, e.g., an ocean, a forest, a desert etc.
Components of Ecosystem
The various components of any ecosystem may be grouped into two main types:
A. Abiotic (non-living) components
B. Biotic (living) components
(A) Abiotic (non-living) components
These include the non-living physico-chemical factors of the environment. These components not only affect the distribution and structure of organisms but also their behaviour and interrelationships.
Abiotic factors include :
(1) Inorganic substances
(2) Organic compounds
(3) Climatic factors
(1) Inorganic substances
Inorganic substances, e.g., carbon, nitrogen, oxygen, calcium, phosphorus etc. and their compounds (water, carbon dioxide, etc.) constitute the main abiotic component. These occur either in the form of compounds dissolved in water in the soil or in free state in air.
(2) Organic compounds
These include carbohydrates, proteins, lipids, nucleic acids etc. These are present in living organisms and dead organic matter. The dead organic matter is broken down by the action of decomposers (e.g., bacteria, fungi of decay) into inorganic substances for their recycling.
(3) Climatic factors
These include light, temperature, humidity, wind, rainfall, water etc. and also edaphic factors (e.g., soil and substrate, topography, minerals, pH etc.).
(B) Biotic (living) components
The living organisms present in an ecosystem form the biotic component. Regarding the mode of obtaining food, the organisms occurring in an ecosystem are classified into three main categories:
(3) Decomposers (reducers).
These include all green plants and blue green algae. These organisms can utilise solar energy with the help of photosynthetic pigments (e.g., chlorophyll) to form glucose (simple carbohydrate) from simple inorganic substances, namely, carbon dioxide and water. This process is called photosynthesis.
6CO2 + 6H2O → C6H12O6 + 6O2
From the basic organic glucose, the plants then form complex organic compounds such as starches, proteins and lipids. As green plants and blue green algae prepare their organic food themselves with the help of sunlight, they are known as photoautotrophs or simply autotrophs.
These are mainly the animals. They are unable to synthesize their food. Therefore, they utilise materials and energy stored by the producers. These also take other organisms. They are known as the heterotrophs.
The macroconsumers are of following types :
(a) Primary or first-order consumers: These include the animals which eat plants or plant products. They are called herbivores.
Cattle, deer, goat, rabbit, hare, rats, mice, grasshoppers are the common herbivores in terrestrial ecosystems, and snails, mosquito larvae, tadpoles, tortoises etc. are the common herbivores in the aquatic ecosystems.
(b) Secondary or second order consumers: These include the animals which feed on herbivores. They are called carnivores. Cats, dogs, foxes etc. are secondary consumers in the terrestrial ecosystems, and water bugs, water beetles, frogs, small fish etc. are secondary consumers in the aquatic ecosystems.
(c) Tertiary or third order consumers: These are larger carnivores which feed on secondary
consumers, e.g., large fish and water birds in aquatic ecosystems, and wolves, snakes etc. in terrestrial ecosystems.
(d) Quaternary or fourth order consumers: These are the largest carnivores which feed on tertiary consumers. They are not eaten by other animals and are also called top carnivores. Tigers and lions are examples in land ecosystems and dolphins and whales are examples in aquatic ecosystems.
(3) Decomposers (reducers)
These include bacteria and fungi of decay. They obtain food from the organic materials of dead producers (e.g., plants) and consumers (e.g., animals) and their waste products.
The decomposers degrade dead remains of plants and animals and waste organic matter into
(a) simple small organic molecules which they utilise themselves, and
(b) inorganic substances that are released into the environment for reuse as raw materials by the producers. The decomposers are also called saprotrophs.
Example of an Ecosystem
(1) Plants like grasses, flower bearing plants (e.g., rose, jasmine etc.) and trees. All these are producers.
(2) Animals such as frogs, insects and birds. All these are consumers. All these living organisms interact with each other and their growth, reproduction and other activities are influenced by the abiotic components of ecosystem.
(3) Decomposers are microorganisms present in the soil. These provide raw materials back to the environment, by decomposition of dead, decaying matter, for their reuse by the producers.