10th Class Science Our Environment Ecosystem


Category : 10th Class

*       Introduction


The total sum of all physical and biological conditions of a place, in which we are living, is called its environment. The physical condition includes; the temperature, pressure, light, soil, etc. and the biological conditions includes the plants, animals and microorganisms around it. Any change in one of these conditions can affect the organisms living in this environment. The energy in the environment comes from different sources and these energy can be used in different forms. We can convert one form of the energy to the another, depending on our requirement. The total energy during a physical and chemical changes remains the same, although it is converted from one form to the another.


*         Ecosystem

An ecosystem is a biological environment consisting of all the organisms living in a particular area. It also includes all the nonliving, physical components of the environment with which the organisms interact, such as air, soil, water and sunlight. The entire array of organisms inhabiting a particular ecosystem is called a community. In a typical ecosystem, plants and other photosynthetic organisms are the producers that provide the food. Ecosystems can be permanent or temporary. Ecosystems usually form a number of food webs. They are functional units consisting of living things in a given area, nonliving chemical and physical factors of their environment, linked together through nutrient cycle and energy flow. The different types of ecosystems are:

  • Terrestrial ecosystem
  • Aquatic ecosystem
  • Lentic, the ecosystem of a lake, pond or swamp.
  • Lotic, the ecosystem of a river, stream or spring.
  • Artificial, ecosystems created by humans.

Central to the ecosystem concept is the idea that living organisms interact with every other element in their local environment.


*           Biomes

Biomes are a classification of globally similar areas, including ecosystems, such as ecological communities of plants and animals, soil organisms and climatic conditions. Biomes are defined on the basis of the factors, such as trees, shrubs and grasses; leaf types i.e. broadleaf and need leaf, plant spacing forest, woodland, savanna and climate. Unlike ecozones, biomes are hot defined by genetic, taxonomic or historical similarities. Biomes are often identified with particular patterns of ecological succession and climax vegetation.

A fundamental classification of biomes is:

  • Terrestrial (land) biomes.
  • Freshwater biomes.
  • Marine biomes.


*            Components of an Ecosystem

We have learned about the parts of an ecosystem, climate and soils previously. From this we can have a basic understanding of the diversity of plants and animals, and how plants and animals and microbes obtain water, nutrients, and food. We can classify the organisms into two parts as biotic components and abiotic components. The biotic components include plants, animals and microorganisms; whereas the abiotic components include temperature, light, land, water, sunlight etc. Usually, biological communities include the "functional groupings". A functional group is a biological category composed of organisms that perform mostly the same kind of function in the system. For example, all the photosynthetic plants or primary producers form a functional group. The two process in the ecosystem are energy flows and ecosystems a material cycle. These two processes are linked, but they are not quite the same.


Energy enters the biological system as light, or photons, is transformed into chemical energy in organic molecules by cellular processes including photosynthesis and respiration, and ultimately is converted to heat energy. This energy is dissipated, meaning it is lost to the system as heat. Once it is lost it cannot be recycled. Without the continued input of solar energy, biological systems would quickly shut down. Thus the earth is an open system with respect to energy. Elements such as carbon, nitrogen, or phosphorus enter living organisms in a variety of ways. Plants obtain elements from the surrounding atmosphere, water, or soils. Animals may also obtain elements directly from the physical environment, but usually they obtain these mainly as a consequence of consuming other organisms. These materials are transformed biochemically within the bodies of organisms, but sooner or later, due to excretion or decomposition, they are returned to an inorganic state. Often bacteria complete this process, through the process called decomposition or mineralization.

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