34. Man and his Environment

Environment : Plants, animals, viruses, microbes and non living things such as light, heat, soil, air, water houses and minerals constitute our environment.
Composition of air
Nitrogen 77.17%
Oxygen 20.60%
Carbondioxide 0.03%
Water Vapour 1.40%
Argon and other gases 0.94%
Others 0.80%
Biosphere : All the biomes taken together as a bigger unit constitute a single large self-sustaining biological system called biosphere. It has a structure, comprising living and non-living components. Each component performs a certain function.
Ecosystem : A community of organisms consisting of producers, consumers and decomposers interacting with one another and with the environment e.g., a pond or a sea-shore.
Population : It is a group of individual organisms of the same kind together in a particular area at a given time.
Community : The assemblage of various populations of different organisms in an area.
Biome : All the ecosystems taken together in a geographical area having the same type of climate.
Atmosphere : The non-living components of the biosphere consists of a matter of substances such as air, water, soil, minerals. The factor such as light, temperature, humidity and pressure constitute climatic conditions.
Lithosphere : The solid upper surface or crust of the earth.
Hydrosphere : The sphere of water on the surface of earth.
Abiotic components : The non-living components of the biosphere. It consists of non-living substances and environments such as soil, water, air.
Biotic components : The living components of the biosphere.
Producers : The organisms which are able to synthesise their own food.
Consumers : The organisms which consume other organisms or their products as their food.
Herbivores : These are organisms (animals) which get their food by eating the producers (plants) directly means plant eaters.
Carnivores : These are organisms (animals) which consume other animals means meat eaters.
Omnivores : Organisms which eat both plants and animals.
Decomposers : The organisms which feed on the dead bodies and remains of plants and animals.
Food Chain : The producers, consumers and decomposers represent the living component of biosphere. This interaction is through food preparation and consumption. The sequential process of one organism consuming the other form a food chain. It is represented as
Food Web : The network of various food chains which are interconnected at various trophic levels.
Trophic Level : The various levels or steps in a food chain at which the transfer of food (or energy) takes place form one organism to another.
Ten Percent Law : According to ten percent law, only ten per cent of the energy entering a particular trophic level is stored and the remaining is lost during the transfer.
Ecological Pyramids : The graphic representation of a specific parameter (such as number, biomass or energy) of a food chain.
Flow of Energy : Following points show the flow or transfer of energy.
(i) Energy is converted from one form to another.
(ii) There is a continuous transfer of energy from one trophic level to the next in the food chain.
(iii) The amount of energy available is less at each successive level than the energy at producer level.
Cycling of Materials : The minerals are absorbed by the plants from the soil or water, CO2 from air and are used in photosynthesis. The main elements are C, N, O, S, P and water. These substances after entering the producer level in ecosystem get transferred to other levels. The transfer and circulation of these substances takes places through soil, water, air and living organisms. The cycling of these chemicals in an ecosystem and ultimately in biosphere is referred to as Bio-geochemical cycles. These cycles can be represented as:
Grass—Sheep or goat—Man
(Absorbs (Receives chemicals (Receives chemicals as food) chemicals from soil) as milk and meat)
Biogeochemical Cycles : The circulation of essential chemical nutrients in a biosphere.
Nitrogen Assimilation : The process of conversion of inorganic compounds of nitrogen into organic compounds that become part of living organisms.
Ammonification : The process of conversion of complex organic compounds like proteins into ammonia.
Nitrification : The process of conversion of ammonia into nitrites and nitrates.
Denitrification : The process of conversion of nitrate salts present in the soil to free nitrogen.
Micronutrients : The nutrients required by living organisms in small amounts.
Biological Fixation : The fixation of nitrogen by bacteria and algae.
Water Cycle : Water circulates in environment. It is known as hydrological cycle. The water loss through transpiration in plants is the major source of evaporation. In atmosphere, water remains in the form of water vapour suspended in air. Most water gets evaporated from seas, rivers, ponds and lakes. At low temperatures, droplets fall as rain and thereby water returns to earth. The water cycle makes the fresh water available to the organisms.
Carbon Cycle : Carbon is a basic constituent of living organisms. It exists as carbohydrates, fats, proteins and nucleic acids. Carbon is transferred through the food chain.
Nitrogen Cycle : Nitrogen is also an important constituent of tissues of living organisms. It is an essential part of proteins, amino acids and nucleic acids. It cannot be utilized by living organisms in its elementary form. It has to be converted into usable form i.e. nitrates.
Oxygen Cycle : Oxygen forms about 21 percent of the gaseous components of atomsphere. It is present in the dissolved form in the water bodies and helps in the survival of aquatic life. Oxygen also enters and leaves the living body in the compound forms as CO2 and H2O. Organisms play major role in striking a balance between oxygen and carbon dioxide.
Atmosphere : The air envelop which surrounds the earth.
Air : The homogeneous mixture of nitrogen (78%) and oxygen (21%). It also contains small quantities of gases such as carbon dioxide, noble gases, hydrogen and oxides of nitrogen.
Particulates : Finely divided solid or liquid particles suspended in air is called particulate matter.
Air pollutants : The substances which pollute the air.
Dust : The solid particles suspended in air.
Smoke : It consists of tiny particles of carbon, oils etc. which are formed due to incomplete combustion of a fuel.
Fog : The minute water particles which remain suspended in air near the surface of earth.
Smog : It is the mixture of fog and smoke.
Aerosols : A colloidal suspension of solid or liquid particles suspended in a gas.
Green House Effect : The heating of atmosphere due to absorption of infra-red radiations by carbon dioxide molecules.
Corrosion of Metals : It is the slow destruction of metals as a result of chemical attack by air, moisture and pollutants present in the atmosphere.
Radioactive pollution : It is that phenomenon in which the nuclei of atoms of certain unstable elements undergo spontaneous disintegration and emit alpha, beta particles and gamma rays.
Noise pollution : The disturbance produced by the undesirable loud sound in the environment is called noise pollution.
Rusting : Formation of hydrated iron oxide on the surface of iron due to its interaction with moisture and air.
Ecology : The branch of science which reveals the interrelationship or, interaction between vegetative and organic environment is called ecology.
Ecosystem : The functional unit of ecology which deals with the interrelation between the living and non-living objects of the environment is called ecosystem.
Autotrophs : Chlorophyll containing green plants are called autotrophs. They act as producers in an ecosystem.
Hydrosphere : Three parts of the earth is water and one part is land. The water content of the earth is called hydrosphere which consists of ponds, pools, rivers, lakes, seas and oceans.
Lithosphere : The solid part of the earth crust forms the lithosphere. Lithosphere includes soil, rocks, etc.
Abiotic constituents, Biotic Constituents : e.g.; Light temperature, pressure, soil, water, carbon dioxide, minerals, chemical compounds etc.
Producers : Green plants are called producers.
Decomposers : Algae, Green flagellates e.g.; bacteria and Fungi.
Consumers : e.g.; Animals.
Type of ecosystems
I. Natural ecosystems
(A) Aquatic (or water).
(i) Freshwater (or Limnetic)
(a) Lentic (or standing water formation)
(1) Pond, (2) Lake, (3) Swamp,
(4) River.
(b) Lotic (or running water formation)
(ii) Marine (or sea). Under this there are tree types.
(5) Sea, 6) Rocky shore, (7) Coral reaf.
(iii) (8) Estuary (or River-mouth)
(B) Terrestrial (or land). The following types are recognised under this. (9) Trophical deciduous forest (11) Temperate deciduous forest, (12) Coniferous forest (or Taiga), (13) Desert, (14) Prairie (or Grass land).
II. Artificial (or man engineered) ecosystems :
(1) Cropland (terrestrial).
(2) Garden (terrestrial)
(3) An Aquarium.
III. Microecosystem : This is the artificial ecosystem, prepared in the laboratory by man, where the communities consist mainly of microorganisms.
Homeostasis : Homeostasis means maintenance of relatively constant conditions either within organisms or within the ecosystem.
Trophic level : The trophic structure of the ecosystem indicates the food relationship between the producers and consumers. And the food level in each step is called the trophic level. Standing crop is a term applicable to the amount of living material present in the different tropic levels in the ecosystem. Biomass the total amount living material (both plants and animals) in a given area is known as the biomass.
Standing state : The amount of non-living materials present during the particular period may be termed the standing state.
The Ecological Niche : The habitat of an organism may be defined as the place with a particular kind of environment inhabitated by the organism. And the role played by the organism in the ecosystem is known as the ecological niche.
Ecological Dominants : Species of organisms, with large numbers, dominating the community are it called ecological dominants.
Soil : It is defined as the weathered superficial layers of earth’s crust which is capable of supporting life.
Humus of Soil : It is formed due to decomposition of dead animals, plants and micro-organisms.
Humification : It refers to the process of humus formation.
Soil Erosion : It is the loss of top fertile layers of soil by wind or by floods.
Sandy Soils : 70-80% sand, 10% slit, 10% clay.
Clay Soils : Very high percentage of clay mixed with silt and humus.
Silt Soil : It consists mainly of silt particles.
Loamy Soil : 40% fine sand, 30-50 silt, 10-15% clay and rest humus.
Hydrological Cycle : The circulation of water molecules through atmosphere and land is known as hydrological cycle.
Humidity : When water in the form of invisible vapour is present in atmosphere, it is called atmospheric humidity.
Cloud : When water occurs in a visible form in the atmosphere, it is called either fog or cloud.
Troposphere : The amosphere overlying the land water surface is called troposphere. It extends up to 10 km above the land water surface.
Stratosphere : It lies above troposphere and is full of ozone.
Thermosphere : It is above stratosphere and is not fit for living. In this part the maximum absorption of radiation rays occur.
Biosphere : It is the part of the universe that supports life.
Concasoid : A race of man of which we Indian belong.
Technology : It consists of converting a non-resource into a source.
Communication : It refers to the mechanism of exchanging information among the various members of the species of a population.
Competition : The interaction between two or more species or between individuals of a species, in which a required source is in limited supply and consequently one or both of the competitors suffer in their growth and survival.
Demography : It is the branch of science that deals with the study of trends in human population of future developments.
Edaphic Factors are the factors related to soil.
Emigration means moving out of an individual from a population.
Immigration means moving in of a species from outside in a population.
Natality : Meaning birth or hatching or germination.
Reproductive Isolation : Means inability to inbreed.
Biotic Succession : It refers to a series of changes until a group of organisms is established, which can live and produce most successfully.
Camouflage : It refers to colour and patterns of animals which blend with their environment so as to minimise the risk of predation.
Climax or Climatic Climax : It is a state in the development of an ecosystem where there is no more net growth in biomass.
Space Biology : It is the study of living organism and their surrounding environment in the outer spaces like moon and jupiter.
Nuclear Biology : It is the study of affects of radiation and chemicals on the living organisms.
Exobiology : It is the study of living organisms in the universe.
Pollution : It is the addition or subtraction of some elements to or from the physical sources such as waer, air or soil that may change their natural composition.
Air Pollution : It is the release of some undesirable elements or gases into the atmosphere which are harmful to man, vegetation, animal and buildings.
Aerosols are the chemicals released into the air with force in the form of vapours from jet aeroplanes.
Water Pollution : It refers to the presence of some organic, inorganic, biological, radiological substances in water which tend to make the water unfit for human consumption.
Energy is the capacity to do work.
Antibiotics are those chemicals which are produced by micro-organism that inhibit the growth of anotehr micro-organism.
Non-renewable Resources : The resources which cannot be reproduced after exhaust are known as non-renewable resources e.g. petroleum, coal, copper, iron etc.
Ecological Balance : In nature, there exists an ecological balance. It means that the activities of various organims in the environment which interact with each other are so finely balanced that they are in equilibrium or in steady state.
Pollutant are those substances which create pollution.
Acid Rain : Automobiles running on petrol emanate huge quantities of sulphur compounds in the air. During rains these compounds get dissolved in the rain water and make it acidic. The process cleanses the atmosphere but the acidity of rain water is harmful to plants and even to historical monuments.
Commensalism : It refers to an association between two species in whcih one gets the benefit and the other is unharmed or unaffected.
Primary Succession : It includes the changes that occur when living things become established on a sterile area.
Secondary Succession : Regeneration of community occurring after an early community has been damaged.
Symbiosis : It is an association of two species of organism where both the partners derive the benefit from each other.
Mimicry : It is a protective device developed by insects and other animals by developing a superficial resemblance in colour and shape to the plant parts on which they live.
Scavenging : It is direct food relationship where animals such as a vulture or a hyena feed on other animals which have died naturally or have been killed by another animal.
Nudation : Means development of bare area without any form of life.
Invasion : It is the successful establishment of a species in a bare area.
Abyssal : It refers to the deep ocean area of perpetual darkness.
Agroecology : It is the study of relationship between agriculture, crop and environment.
Agroecosystem : Man made crop land ecosystem.
Estuary : It refers to the channel of river submerged in the sea due to rise of sea level.
Eutrophication : It means enrichment of a habitat with nutrient elements.
Nerictic : It refers to organic shallow water.
Photic zone : It refers to the depth in the sea where sunlight can penetrate and help in photosynthesis.
Photoplankton : It are capable of synthesizing the food in the presence of sun light.
Topography : It refers to the surface configuration of an area.

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