Environment Management

ecosystem

Name Of MembersShivamRaviJaiSimarpalJaskaran HimanshuRoyNavilVikasPetrickImranPranavShikhaPoonamVigneshNilofer

Meaning Of Ecosystem• The term ecosystem was first used by A.G.Tansley in 1935. He defines

the term ‘ecosystem’ as “a particular category of physical systems consisting of organisms and inorganic compounds in a relatively stable equilibrium, open of various sizes and kinds.”It is comprised in two major parts i.e. Biome (the whole complex of plants and animals of a particular spatial unit) & Habitat (physical environment)

• The example of a fish in the lake or a tree in the forest indicate clearly that if we want to understand the living of different organisms and their habitats properly, then we must not considered them in isolation. We must consider them as a part of an interacting system.

• The examples of natural ecosystems are ponds, lakes, grassland, desert, etc. In these ecosystems the biotic and the a biotic environment interact in different ways and work like a system. Biosphere in other words is said to be the parts of Earth where atmosphere, the hydrosphere and lithosphere have met through which life has become possible.

Kinds of Ecosystem:

Ecosystems

Natural Ecosystem

Terrestrial

Aquatic

Fresh water

Marine

Artificial Ecosystem

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Functions of Ecosystems:

• Functions of any ecosystem mainly refer to the interaction between biotic and a biotic components. The primary interactions between these two components are influenced by the ultimate source of energy i.e. Sunlight.

Functions of Ecosystems

Photosynthesis Energy Flow Material Cycling

Energy Material Flow:

• The most important feature of all ecosystems is the flow of energy because ecosystems depend on a steady and regular supply of energy to maintain structural organization and carry out all life preserving activities.

• The most important step to provide energy for all the organisms in the ecosystem is the ultimate source of energy i.e. Sun. The average energy reaching on the earth surface is about 2 cal/ Out of this huge solar energy only about 5% solar energy is converted into chemical energy by plants.

Continued…….• The initial conversion of solar energy into chemical

energy by the primary producers is the most important step in providing energy for all other living organisms in any ecosystem. The movement of energy is through the process of eating. No energy can be created or destroyed.

• The energy from the sun is used up by plants. This energy is transmitted to the herbivores, and further is transferred to carnivores. Then the dead bodies are consumed by the scavengers and microorganisms present in the soil. The dead organic matter is consequently released into the soil in the form of nutrient pool. The matter provided by nutrient pool is used by plants in the manufacture of food. Hence, it can be seen that energy flow is unidirectional but material flow is cyclic in nature.

Food Chain and Food Web:-

• The point where food energy is transferred from one group of organisms to the other group is known as tropics level.

• A simple sequence of organisms such as a plant, an insect, etc. which feed on one another, form a food chain.

• Plants form primary tropics level, the insects form the herbivore tropics level, the snake eating frog form the carnivore tropics level and a bird eating a snake form the top order tropics level.

• Many food chains operate simultaneously. Many times these food chains are connected to each other. Example plant may form food for many herbivores, which in turn may form food for carnivores and so on. Hence, these food chains are interconnected to form a food web. It is very complex.

Plants Herbivore Carnivore (first)

Carnivore (second)

Ecological Pyramids:

• It refers to the representation of trophic level and functions of an ecosystem graphically. These are three types of ecological pyramids:-Pyramid of Numbers

Pyramid of Biomass Pyramid of Energy

It depicts the number of organisms at each trophic level. The pyramid may be inverted or upright.

It is based on total biomass at each trophic level in a food chain. The pyramid may be inverted or upright

It depicts the amount of energy present at each trophic level. This pyramid is always upright.

Characteristics of Resources:

• A substance is merely part of nature until a society has a use for it. Consequently a natural resource is defined by three elements of society:

a) A society’s cultural values influence people’s decision that a commodity is desirable and acceptable to use.

b) A society’s level of technology must be high enough to use the resource.

c) A society’s economic system affects whether a resource is affordable and accessible.

• Let us consider petroleum as an example of a natural resource in North America:

• Cultural Values: North Americans ant to drive private automobiles rather than public transports.

• Technology: Petroleum is the preferred fuel in private automobiles because these are easily powered by gasoline engines.

• Economic system: North Americans are willing to pay high enough prices for gasoline.

• The same elements of society apply to the study of any example of a natural resource i.e Rice to the Japanese, Diamonds to the South Africans, Forests to the Brazilians, and air quality to Los Angeles. A combination of three factors is necessary for a substance to be valued as a natural resource. Differences in these three factors help geographers to understand why a resource may be valuable in one place and ignored elsewhere.

Types of Resources:

• A natural resources can be of the following types:

i. Biotic and A biotic resources.

ii. Renewable or Flow and Non-Renewable resources or fund.

Biotic Resources Abiotic ResourcesA biotic resource is the resource which is directly or indirectly derived from photosynthetic activity of green plants. For example Food fruits, wood, fibre, milk and milk products, fish meat, leather,etc.are termed as biotic resource. Coal, oil and natural gas are also biotic resource as they were produced by photosynthetic activity of plants which occurred millions of years ago.

Mineral material, fresh water, rocks, salts, and chemical, etc. are termed as abiotic resources as biological activity is not involved in their formation.

Continued………..Renewable or flow resources Non-renewable resources

They are replaced continually at least within a human lifespan and can be regenerated. These resources have the capacity to replenish or renew by themselves. Solar energy, air, wind, water, trees, grain, livestock are some examples.

They form so slowly that for practical purposes they cannot be replaced when used i.e they cannot be regenerated once they are exhausted. Coal, oil, gas and ores of uranium, aluminium, lead, copper iron, etc. are some examples.

Limitations of Renewable resources:

• Most of the biotic resources which are developed as a result of only recent photosynthetic activity of green plants are renewable in nature. The biosphere constitutes an excellent life support system which can fulfill all human needs. But its size and productivity is limited by availability of water, nutrients and environmental conditions.

• Though an enormous quantity of water is present on our planet, for fresh water life depends largely on precipitation, which too is available only in a finite quantity annually. Its uneven distribution over earth’s surface has caused large surface area to become deserts. A large part on earth’s surface is too cold or rocky for any productive use, whereas a large area has to be devoted to forests and wildlife which due to their obvious importance cannot be curtailed beyond certain limits. This leaves only a limited area at our disposal for agriculture and pastures.

• Growing more and more from the same crop fields involves expensive use of fertilizers, energy input, irrigation and high yielding varieties. Global livestock and fisheries resources can also not be expanded beyond certain limits. It is only upto a limited extent that resources of biosphere can be safely exploited. Over exploitation tends to damage the biotic system and thereby the overall productivity. It could cripple the very resource base which is so important to our existence. They cannot be stretched beyond a certain limit. With careful management this limit can be enlarged.

Finite Nature of Natural Resources:

• Neither energy nor matter can be created or destroyed. No one, howsoever advanced technology, can create something out of nothing nor can anything be so discarded as to become nothing. A constant flow of materials is needed to maintain living beings, a society, or an economy which must come from somewhere, whereas a continuous stream of wastes discarded has to go somewhere. The total amount of matter present on our planet is fixed except for cosmic particles entering and some gases leaving from outer atmosphere. This has been so throughout the known history of our planet the elemental composition of earth’s atmosphere, hydrosphere and the lithosphere is fixed, stable and known.

• The enormous changes which take place everyday involve changes in the state, mix and distribution of materials on earth. Volcanoes erupt, emit lava, ash and gases, create new islands or bury cities. Each year man extracts billions of tons of materials and fuels from earth, transforms them chemically creating new molecular combinations which never existed before. All these activities require energy, which comes only from just two sources – the incoming solar radiations and the residual heat of earth’s core. Fusion energy is the only source of energy which man has not been able to harness till date.

Continued………• In other words, as far as matter is concerned, our planet

is nearly a closed system – nothing enters or leaves it. It regularly receives large amounts of energy from sun, much of which has to be re-radiated back to space in order to maintain a heat balance. Therefore, mankind’s immediate environment, the planet earth, is limited in size and space as well as in its material resources. There is a constant entry of energy into the system as solar radiation, however, material resources of our planet are fixed in quantity and have to be used again and again in a cyclic fashion.

Conservation of Resources:

• Conservation may be defined as “careful and rational use of resources and their preservation from reckless exploitation and destruction. It means judicious use of resources to preserve for future needs. It includes control and management of resources in such a way that they will be useful to man forever.”

• Excessive exploitation, high rate of consumption and misuse, etc. are considered as dangerous as it would lead to their depletion. Rapid growth of population during the last 100 years and rising standard of living and per capita income are likely to increase the rate of exploitation and consumption of many natural resources. Conservation of exhaustible resources is very urgent need of the time.

• For example “power resources like coal or oil, once we burn, it vanishes. It cannot be used again. Conservation of such resources therefore, is must, otherwise within next few hundred years, there would not be any coal or oil, left for the future economic development. Such resources must be used only when their use is most essential, or we must find out substitutes for them so that we can use them for longer time.”

Methods of Conservation of Some Resources:

Soil

Natural Vegetation

Minerals

Water

Wealth:

• Wealth is goods and services owned. In popular usage “wealth” can be described as an abundance of items, usually in the form of money, real estate and personal property. An individual who is considered wealthy, affluent, or rich is someone who has accumulated substantial wealth relative to other in their society or reference group.

• In economics, wealth refers to the value of assets owned minus the value of liabilities owned at a point in time. Wealth can be categorized into three types i.e Personal property, including homes or cars, money savings and the capital wealth of income producing assets, including real estate, stocks, bonds, etc.

• Wealth refers to accumulation of resources ‘Richness’ refers to abundance of such resources. A rich individual or community or country, thus has more resources than a poor one The concept of wealth is relative. For example a person with US $10,000 in USA may not be considered as wealthy person but “a person with same amount in countries like Bangladesh will be considered as wealthy person.”

Man and Global Resources:

• Systematic exploitation, modification and destruction of natural ecosystems began right from the time when man learned to use fire, domesticate animals and grow plants for food. Man’s interaction with the environment can be divided into three phases. These are the phases:

I. The phase of food gathering and hunting.

II. The phase of plant and animal domestication, pastoralism and settled agriculture.

III. The phase of science, technology and industrialization.