4. Environmental Management

4. Environmental Management Can you recall? 1) What is ecosystem? Which are its different components? Ans. In any environment, there are biotic and abiotic components. There are interactions among these components. All such interactions make an ecosystem. The different components in the ecosystem are as follows: Abiotic components : Air, Water, soil, sunlight, temperature, humidity, etc. Biotic components : All the types of living organisms, like bacteria, fungi, plants and animals. 2) Which are the types of consumers? What are the criteria for their classification? Ans. Primary consumers, secondary consumers, tertiary consumers or apex consumers are the different types of consumers. These types are according to the trophic level to which they belong. 3) What may be the relationship between lake and birds on tree? Ans. The birds on the tree depend on the aquatic organisms in the lake for their feeding. Birds stay on the trees which are in the vicinity of the lake, so that it is easier for them to capture fishes, frogs, etc. They must also be using the same lake water for drinking. 4) What is difference between food chain and food web? Ans. In every ecosystem, there are always interactions between producers, consumers and decomposers. This sequence of feeding interactions is called food chain. In every food chain there are links between four to five trophic levels constituting the producers, primary consumers, secondary consumers, tertiary consumers etc. The links of food chain are in linear sequence. But food web is complex network of many small food chains. In fact, food web is the collection of many small food chains. Thus, when many food chains are interwoven, they form food web. Think and Answer! 1) Write the name and category of each of the component shown in picture. Ans. By utilizing the solar energy, the green plants perform photosynthesis. Thus, they are producers of the food chain. This food is consumed by the grasshopper. Thus, it is primary consumer. Frog is secondary consumer as its diet consists of insects like grasshopper. Snake is tertiary consumer as it feeds on frogs, while the hawk is apex consumer as it can kill the snake and feed on it. Last picture in the food chain is of fungi which are acting as decomposers. Few bacteria are Food chain shown in the picture act on all the levels and are bring about decomposition. 2) What is necessary to convert this picture into food web? Why? Ans. If this food chain has to be converted into a food web, there should be interactions between the different components. Any living organism can be prey to different predators. Moreover, a predator can also be a prey for other. Frog eats different insects. The same frog can be either eaten by snake or by hawk. Ecosystem A review Biotic and Abiotic factors and their interaction with each other form an ecosystem. Every factor has important role to play for functioning of the ecosystem. Various herbivores like deer, goats, sheep, cattle, horses, camels, etc. feed upon producers. Carnivorous predators e.g lion and tiger control the population of the herbivores. The decomposers and scavengers like caterpillars, termites, insects present in the dung carry out decomposition and thus clean the environment. Existence of human beings is dependent on the balanced ecosystem. Think If fallen foliage in forest, dead trees, and caracasses in and around villages had not been decomposed for years…. Ans : i) If fallen foliage in forest, dead trees, and carcasses in and around villages had not been decomposed for years, they will remain as it is nature. ii) Complex carbon substances from fallen foliage in forests, dead trees, caracasses, etc., are converted to simpler carbon compounds by decomposers. iii) Due to decomposition, these carbon compounds easily mix with air, water and soil from where they are again absorbed by plants and incorporated into the food chain. iv) If these materials are not decomposed by decomposers, recycling of various compounds from biotic to abiotic components won’t be possible and the ecological balance would be disturbed. Discuss : ‘Jivo Jivasya Jivanam’ Ans. ‘Jivo Jivasya Jivanam’ is a Sanskrit saying which means that one living organism makes the living of the other. All the food chains occurring in the nature, function on this principle. Prey and predator interactions are based on the above concept. While discussing, students should give various examples that occure in their surrounding environment. Can you recall? 1) Which are different trophic levels in food chain? Ans. The different trophic levels in food chain are producers (First trophic level), primary consumers (Second trophic level), secondary consumers (Third trophic level), tertiary consumers (Fourth trophic level) etc. 2) What is energy pyramid? Ans. Energy pyramid is the diagrammatic representation, that depicts the energy levels at the various trophic levels. There are interactions in the form of energy transfer in all the food chains and food web. The energy pyramid shows how energy travels up a food chain. Let’s think A bird building nest on a tree feeds upon the fishes in nearby pond. Whether this bird is part of both i.e. tree as well as pond ecosystem? Ans. i) Yes, the bird becomes the part of both tree and pond ecosystem. ii) Birds perched on trees feed upon the fishes in the nearby pond and are this a part of the pond ecosystem. iii) This bird builds its nest on a tree and hence is also a part of the tree (terrestrial) ecosystem. iv) The role of bird in pond ecosystem can be explained by the following food chain : Pond ecosystem: Algae Small fishes Big fishes Bird (Producer) (Primary (Secondary (Teritary Consumer) consumer) Consumer) Complete the chart : Paddy is cultivated on large scale in various states of South India. Paddy are frequently attacked by grasshoppers. Similarly, froges are also present therein to feed upon their favourite food-frogs. However, if frog population declines all of a sudden. Let’s think – 1) What will be the effect on paddy crop? Ans. If the population of frog declines, then there will be rise in the population of grasshoppers. The paddy fields will hence be infested with insect pests. 2) Number of which consumers will decline and which will increase? Ans. The food chain if altered, result in imbalance in the ecosystem. ‘Paddy Grasshoppers Frog Snake’ , this food chain is natural. When by any reason there is decline in the number of frogs, thus secondary consumer will decline. Due to this decline, snake which is at tertiary consumer level will also decline. The primary consumers i.e. grasshoppers will increase as there is now no check on their population. Due to increase in their population the paddy production will be reduced. Due to reduced number of snakes, rats and other rodents from neighbouring areas would also rise, which are also secondary consumers. 3) What will be overall effect on that ecosystem? Ans. If frogs’ population declines, there would be imbalance of entire ecosystem. The number of prey and predator populations will change and thus the food chain will come to and end. Can you tell? i) What is environment? Ans. The physical, chemical and biological factors which influence an organism collectively is called as environment. ii) What is included in environment? Ans. Environment includes biotic and abiotic factors. Relationship between Environment and Ecosystem – Physical, chemical and biological factors affecting the living organisms in any possible way is collectively called as environment. It includes many biotic, abiotic, natural and artificial factors. two types of environment 1) Natural environment :- Naural environment consists of air, atmosphere, water, land living organisms etc. 2) Artificial environment :- Artificial environment consists of two basic factors Biotic factors and Abiotic factos. The science that deals with the study of interactions between biotic and abiotic factors of the environment is called as ecology. Environment consists of many ecosystem. In brief, biotic and abiotic factors occupying a definite geographical area and their interactions collectively constitute the ecosystem. Environment balance is maintained through continuous of various natural cycles like water cycle, carbon cycle, gaseous cycles like nitrogen cycle, oxygen, cycle etc. Environmental balance is also maintained due to various food chains of ecosystem. Can you recall? • Which cycles are operated in environment? What is their importance? Ans. The different cycles that operate in environment are water cycle, carbon cycle; gaseous cycles such as nitrogen cycle, oxygen cycle; sedimentary cycles such as phosphorus cycle, calcium cycle, iron cycle; etc. Human existence is totally impossible without the existence of nature. Hence, it is basic responsibility of human being to preserve the nature without disturbing its balance. It is said that we have got this Earth planet on lease from our future generations and not as an ancestral property from our ancestors. Hence we should not forget to conserve it for ourselves and for future generations. Can you tell? • Which factors affect the environment How? Ans. The natural as well as artificial or manmad factors affect the environment. Among natural factors, the sudden changes in the weather, the different types of natural disasters, etc.affect the normal environment. Due to such changes there are problems in the interrelationships that exist between food chain and food web. Due to various man-made causes, there are extreme destruction of environment. Industrialization, the pollution due to such industries, Urbanization, hunting and poaching of wild animals, construction of dams, roads, bridges etc are all man-made changes that cause lot of damage to environment. 2) What will happen if number of consumer in environment goes on increasing gradually? Ans. If number of consumers increase graduall, it will create the scarcity of prey organisms. Then due to lack of prey, the number of consumers will also decline.

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