Class 10 Biology Notes For Structure, Functions, Units and Types of Ecosystem

Ecosystem- What Are Its Components

How do living organisms and physical beings interact with each other to maintain a balance in nature?

An ecosystem (Tansley, 1935) is a self-sustaining nature that consists of a distinct Vegetation community of living organisms and physical components of the environment, all interacting and exchanging materials amongst themselves.

An ecosystem is the structural and functional unit of the biosphere. For its sustenance, each ecosystem requires a regular input of energy and circulation of materials.

Ecosystem may be small or large, natural or artificial, permanent or temporary, terrestrial or aquatic. Two large natural ecosystems are ocean and forest The largest artificial ecosystem is agro-ecosystem.

An artificial ecosystem requires human support for its persistence. Visit your school garden which is also an artificial ecosystem. See that the gardener has grown grass, trees, bushes, flower-bearing plants like rose, jasmine, sunflower, etc.

Some animals are also found in the garden, Example ants, frogs, butterflies, honey bees, squirrels, birds, etc. Aquarium is also human human-supported artificial system.

Activity 5.3 Aquarium— An Artificial Ecosystem

A common aquarium kept in a household is a large-sized glass box in which small-sized fish are reared in freshwater. The aquarium has an aerating pump and light.

Many small water plants like Hydrilla are also planted to augment the availability of oxygen. Some small aquatic animals like snails may also be added. Fishes are provided with fish food at regular intervals.

It is available in the market. After 3-4 weeks the aquarium is cleaned of debris as the decomposing system cannot cope with the decaying materials.

Components of Ecosystem

An ecosystem has two types of components-abiotic and biotic.

Abiotic Components

They are nonliving substances and physical factors of the ecosystem. Among the physical factors are climatic factors, edaphic factors, and topographic factors.

1. Climatic Factors. They include duration and intensity of light, temperature, periodicity rainfall, humidity, and air currents.
2. Edaphic Factors. They are soil factors like the type of soil, its, nutrients, and soil water.
3. Topographic Factors. They are the nature of the area like plains, mountains, valleys, etc.
4. Non-living Substances. They include inorganic nutrients and organic remain

Biotic Components

Biotic components are various types of living organisms present in an ecosystem. They show many types of interactions and interdependence.

The whole group or assemblage of living organisms found in an ecosystem is called a biotic community. It consists of three groups— producers, consumers, and decomposers.

While producers are autotrophs the Other two are heterotrophs. HeterotroPhs obtain readymade food while autotrophs manufacture their food.

1. Producers. They are autotrophs that manufacture their food from inorganic raw materials with the help of solar energy absorbed by chlorophyll. The process is called photosynthesis.

Photosynthesis is performed by green plants, algae, phytoplankton, blue-green algae, and some bacteria.

Two things occur in photosynthesis the conversion of solar energy into chemical energy and the formation of organic food. Organic food is used by autotrophs as well as heterotrophs for bodybuilding and the release of chemical energy.

Autotrophs are called producers because they manufacture food not only for themselves but for all other living beings or heterotrophs.

Functions.

1. Producers convert solar energy into chemical or usable forms of energy. They are, therefore, also called transducers or converters,
2. Producers manufacture food for themselves as well as other organisms.
3. They pick up CO2 and release oxygen in their photosynthesis.

Consumers. They are heterotrophic organisms that feed on other organisms. Consumers are divisible into four categories-herbivores, carnivores, omnivores and parasites. Except for some parasites, plants all others are animals.

1. Herbivores. They are first-order or primary consumers who directly feed on plants and their seeds or fruits. They have special enzymes or symbionts to digest the cellulose of plants, for Example cow, buffalo, goat, sheep, horse, camel, deer, rabbit, mice, squirrels, grasshoppers, etc. Herbivores of aquatic ecosystems are small fish, mollusks, and zooplankton.
2. Carnivores. They are animals that feed on other animals. Primary carnivores or second-order consumers feed on herbivores, for Example frogs, jackals, foxes, wildcats, some fishes, birds, and snakes.
3. Secondary carnivores or third-order consumers prey upon primary carnivores, for Example, peacocks, and snakes feeding on frogs, owls, tigers, and lions, Tigers and lions feeding on deer are, however, primary carnivores.
4. Top carnivores are those carnivores that are not preyed upon by other animals, for Example tigers, lions, sharks, and eagles.
5. Omnivores. They are animals including humans which feed on both plant and animal matter, for Example cockroaches, crows, dogs, bears, and ants.
6. Parasites. They feed on living hosts without killing them. Parasites belong to different groups and attack nearly all types oforganisms. They can be ectoparasites or external parasites (for example Cuscuta, lice) and endoparasites or internal parasites (For example Plasmodium, Ascaris).
7. Functions of Consumers, (z) They exert biological control over different types oforganisms so that the population of all the organisms remains checked, Many consumers help producers in their pollination and fruit dispersal.

Decomposers. They are microscopic saprotrophic organisms (bacteria, fungi) that feed on organic remains. Decomposers secrete enzymes to degrade the organic remains.

The process of decomposition yields two types of substances:

1. Simple soluble organic substances that are absorbed by the saprotrophs.
2. Inorganic nutrients. The release of inorganic nutrients is called mineralization. They are absorbed by plants for the manufacture of food. Being microscopic, decomposers are also called microconsumers.
3. Functions. They are regularly cleaning the earth by feeding on organic remains, They help in the recycling of inorganic nutrients or biogeochemicals.

Activity 5.4 Who Eats Whom?

Study the various populations of a biotic community. It consists of producers, herbivores, and carnivores. Producers manufacture food.

Their number is the largest in an ecosystem. Producers are eaten by herbivores. They keep the population of producers under check. Herbivores are eaten by carnivores.

They keep the population of herbivores under check. Otherwise, the herbivores can destroy the population of producers. The population of carnivores depends upon the population of herbivores. If the herbivore population is small, the carnivores get starved and die.

In an aquarium, if you happen to add a carnivorous fish, the fish population of the aquarium will disappear after some time.

The carnivorous fish will also die after some time. An ecosystem will remain healthy and sustainable if the number of individuals at the lower trophic level is large as compared to some individuals at the higher trophic level.