BIOTIC AND ABIOTIC COMPONENTS OF AN ECOSYSTEM


Abiotic components of an ecosystem:

The nonliving or abiotic components of an ecosystem are:


1. Light

2. Water and humidity

3. Temperature

4. Atmosphere

5. Fire

6. Soil

7. Inorganic nutrients

8. Gravity


1. Light:

       Plant use sunlight during photosynthesis to prepare food.

LIght quality, its quantity and also its duration affects the ecosystem.


2. Water:

       Water is one of the raw material that is used in photosynthesis. Water is a universal solvent and covers more than 70% of the earth surface. It can dissolve minerals in the soil. which are then observed by plants through roots. Depending on the quantity of water, plants are divided into

three groups:


a. Hydrophyles

d. Mesophytes

c. Xerophytes


3. Temperature:

        Temperature plays an important role in the distribution of plants and animals. It affects the growth and function of organisms. The range of temperature for life activities lies between 10°C to 45°C. Certain animals migrate to places of optimum temperature such type of movement is known as "Thermal migration"

       The cells may rupture when temperature decreases below 0°C. The proteins and enzymes may denature at temperature of about 45°C


4. Atmosphere and Wind:

        Atmosphere is the gaseous envelope, which surrounds the earth. It contains Nitrogen (78%), Oxygen (21%) and carbon dioxide (0.04%). The green plants take up nitrogen in the form of nitrates which is used for building proteins. Oxygen is used during respiration and cO, is essential for photosynthesis.

       Air in motion is called "wind". Strong winds damage buds and produces flag from trees. Strong winds causes soil erosion, uproot trees and break the branches. Winds help in pollination and dispersal of seeds.


5. Fire:

      It is an important abiotic factor. It can bring out sudden changes in the ecosystem. Human and lightning are the main causes of fire. Fire changes dry organic matter into soluble ash which is important for the recycling of nutrients. On the other hand, fire destroys an ecosystem by destroying primary producers.


6. Soil:

      Soil is the upper layer of the earth's crust in which plants are anchored. It is a source of water and nutrients for plants. Soil consists of two layers, topsoil and subsoil.


i. Topsoil:

     The upper part which consists of particles of different sizes of the soil is called the topsoil. It is 20 to 30 cm thick and dark brown in colour.


ii. Subsoil:

       It lies below the topsoil. It is a thicker zone and is lighter brown in colour. It consists of large rock particles, stones and water. The best soil for agriculture is loam which contains equal proportion of different soil particles.


7. Inorganic Nutrients:

       Organisms depend on inorganic nutrients like CO2, O2 compounds of calcium, nitrogen and phosphorus etc. A small portion of these in solution form is readily available to the organisms and essential for the growth of the plants.


8. Gravity:

       It is a constant abiotic factor. Roots grow towards gravity to get nutrients. Birds show adaptations to overcome the problem of the gravitational pull. For example, birds posses wings and light bones. Transport of water to upper parts of the plant occurs through xylem cells.


Biotic components of an ecosystem:

       Biotic components are the living part of the ecosystem. It consists of plants, animals and microbes. They can be classified into three types:


1. Producers (Autotrophs)

2. Consumers (Heterotrophs)

3. Decomposers


1. Producers (Autotrophs):

        Producers are the green plants, algae and photosynthetic bacteria. They can prepare their own food by photosynthesis and therefore called autotrophs. They form the basis of an ecosystem. A part of this food is used by the plants themselves, while the remaining part is utilized by the consumers and decomposers. Plants are the producers of land while phytoplankton's (floating plants) are the producers of aquatic ecosystem.


2. Consumers (Heterotrophs):

      Consumers are animals. They cannot prepare their own food. They get their food from the producers therefore called heterotrophs. They are of three types.


a. Primary consumers


b. Secondary consumers


c. Tertiary consumers


a. Primary consumers:

        They are also called herbivores. They feed directly on green plants. Elephant, cows, goats, sheep, rabbits etc are the primary consumers in the terrestrial habitat. In aquatic habitat arthropods, mollusks and some fishes are the Primary consumers.


b. Secondary consumers:

        They feed on herbivores and green plants as well. Those animals which feed on herbivores are called carnivores such as fox, snake, frog, lizard etc.


C. Tertiary consumers:

        They are the top consumers. They get their food from primary and secondary consumers. Lion, tiger and hawk are tertiary consumers.


3. Decomposers

       Decomposers are also called saprophytes. They get their energy by decomposing the remains of plants and animals. They are also called cleaners of ecosystem. Fungi and many types of bacteria are decomposers. They take part in nitrogen cycle and carbon cycle.


Energy relation b/w different trophic level:

       Energy and inorganic nutrients flow through the ecosystem. Sun is the major source of energy for all ecosystems.


(i) Producers get this solar energy and convert in to chemical energy by the process of photosynthesis. A part of this stored energy is converted into mechanical and heat energy during their metabolic activities.


(ii). This energy flows to herbivorous when producers are eaten.


(iii) Herbivorous convert some of their energy to mechanical and heat energy during their metabolic activities and the rest of energy is stored in the tissues.


(iv). Energy flows to carnivores when herbivores are eaten. Energy is consumed in the same way as the herbivores.


(v) Decomposers secrete digestive enzymes into dead matter of animals and plants. Many types of bacteria and fungi act as decomposers.