FST -1

9th Part

Given above is a figure, based on which the following questions are given. Answer them. 

(i) What ecological phenomenon has been depicted in the figure? Define it.

A.  The figure depicts the food chain. Within an ecosystem, there are many different food chains. Some organisms are involved in several of the food chains at the same time. So a number of food chains become interwoven into a food web. interlocking food chains provide stability to the ecosystem.

(ii) Select and name some organisms and use them to prepare a food chain with four trophic levels.

A.   Plants ----> Goat ------> Wolf -------> Lion

B.   Plants ------> Rat -------> snake -------> Hawk

(iii) State the terms for the trophic levels, naming the components of the constructed food chain. 

A.  Solar energy is converted by plants into food materials which are consumed by the goat, the goat is consumed in the next step by the wolf and in the end wolf by a lion which is the last stage.

(iv)  What happens to the energy flow through the constructed food chain? Who gets the least energy and why?

A.  The energy from the producer to the last level decreases considerably. The loss of energy in the form of heat given out by different organisms. Energy flowing through an ecosystem is thus first captured by the producers. From the producers, the energy passes to various consumers, via food. At the end of the chain, we find that very little energy is left for the last trophic level because some energy is always lost in going from one level to the next. This loss of energy limits the number of trophic levels in the ecosystem, and so they are seldom more than five. This also clearly shows that why the steps in a food chain are limited to four or five. Lion gets the least energy. 

(v) Name the principal source of energy for any ecosystem. Is it a renewable or a non-renewable source, and why? 

A.  The principal source of energy for any ecosystem is sunlight which is renewable energy. Solar energy is converted by plants into food materials and is stored within the body of the plant. All food materials that we or other animals consume are manufactured directly or indirectly by plants. It is renewable as it is not coming from fossil fuels.

Q.  Resource Mapping                          

A.  Using various techniques like remote sensing, satellite imaging, etc. resource Mapping is done to locate different resources like water, minerals, forests. vegetation as well as the types of land. Mapping of resources makes it possible to visualize how land use could be managed to the best advantage. The rural land use map tells us about the health of forests and the state of deforestation, about pastures, and agricultural crops. It also tells us how much land and of what kind is unutilized. The urban land use maps show housing, commercial buildings, sports facilities, essential services such as roads, water supply and disposal of waste, etc. Likewise, the preparation of regional land use maps will focus upon the broader aspects of development such as land used for agriculture, industrialisation and urbanization, for obtaining natural resources (forestry, mining etc.), water resource development (dams, reservoirs and canals), transportation network (rails, road etc.) and also the zones prone to natural hazards like floods, cyclones, earthquakes, landslides and avalanches etc.

Q.  Distinguish between renewable and non-renewable resources giving any two examples of each type.            

A.  Renewable - Some of the resources of the earth are replaced from time to time by natural multiplication as for example, is vegetation. In other words, these resources are inexhaustible and are therefore called renewable resources. Forests, pastures, wild life. and aquatic life is renewable resources. Water is also a renewable resource because it recycles.

Non-renewable - There are some resources, such as minerals, coal, petroleum, gas, etc which once consumed are lost forever. They cannot be regenerated nor expanded. Mineral deposits were formed slowly in millions of years. Once a deposit is used, it cannot be regenerated. For example, petrol gets burnt up and cannot be recovered. These are known as non-renewable resources. Similarly, the formation of soil is a very slow and long term process and it takes thousands of years. It is, therefore, not renewable in the life span of even several generations of people. Hence it is also a non-renewable resource.

Q.  (a) Write a brief account on the causes and effects of deforestation in India. Support your answer with appropriate real-life examples. Name the states in India where maximum deforestation has occurred.    

A. Causes for deforestation - 

#  Shifting cultivation, i.e., the process of slashing and clearing of the forest, burning much of the fallen vegetation and cultivating a mixture of crops for two or three years, until the soil loses its productivity is one of the prime reason for deforestation.

#  The conversion of forests to pastures for cattle grazing. 

#  Overgrazing - Grazing intensity is high in most of the forest areas of India. This has depleted vast forest areas. In addition to.depletion of vegetation cover, trampling by cattle, hardens the soil, preventing forest regeneration. When there are no plants, the soil becomes loose, and is lost by winds or is washed off by heavy rains.

#  Commercial exploitation of forests due to the increasing demand for timber is one of the main causes of forest destruction. Wood (for building for making boxes to transport goods, for making paper, and just for burning) is in great demand, and this represents a major threat to our lush green forests.

#  Developmental activities such as irrigation projects, the building of roads, etc. have led to the destruction of forests. This amounts to acquiring good things, like roads, by losing something which is even better.

Effects - Destruction of forests causes soil erosion, silting of lakes & rivers, resulting in devastating floods and loss of thousands of species of plants and animals forever. Trees can grow on hillsides, even when the soil layer is quite thin. When the trees are cut down to clear them for cultivation and the soil is ploughed, there is less protection from the wind and rain. Heavy rainfall washes the soil off the hillsides into the rivers. The hillsides, thus, are left bare and useless, and on the other hand, the rivers become choked up with mud and silt resulting in floods. The disastrous floods in our country have been attributed largely to deforestation.

               The degradation of forests leads to the destruction of habitat for many species of plants and animals. Presently, over one hundred species of wild animals need immediate protection as their population has dwindled to dangerously low levels. Similarly, many plants, too, have suffered from the onslaught of human activities. In a recent list prepared by the Botanical Survey of India, 135 species of Indian plants have been listed, which need immediate protection for their survival. Similarly, over 200 species of animals all over the world have become extinct.

            According to the satellite data, India lost 1.3 million hectares of forest every year between 1972 and 1982. Arunachal Radesh. Manipur and Andaman & Nicobar Islands are the only areas that fulfill-the stipulation of forest cover in hill regions laid down by the National Forest Policy in 1952. The maximum deforestation has occurred in Madhya Radesh, which lost nearly 2 million hectares, Maharashtra lost one million hectares, Orissa, Andhra Pradesh and Jammu & Kashmir lost nearly a million hectares of forest land each during the above said period.

Q.  List the four types of resource maps.   

A.  Four types of resource maps are - 

#  Soil Maps showing the types of soil their composition and biological productivity.

#  Mineral Maps showing locations of various kinds of mineral deposits in relation to settings of the earth's crust.

#  Hydrological Maps show the presence of underground water aquifers, i.e., rock formation containing water in recoverable quantity, in terms of the depth of water table.

#  Snow Cover Maps demarcate the extent of snowpacks on high mountains.

Observe carefully above picture and answer the following questions based on it :

(a)What does the picture depict? Define it.

A. The picture depicts a pond, which is an ecosystem. It is made up of basically two types of components: living and non-living. The living components include various types of plants, frogs, birds, fish, turtle, insects and numerous kinds of microscopic life forms called microbes. The water, the dissolved gases such as oxygen, and carbon dioxide, the minerals, soil, and stones constitute the non-living components. The various components of the pond interact with each other. The pond is a small world in itself. Here living organisms are born, they live, breath, feed, excrete, move, grow, mate, reproduce, become food for each other and die within the pond itself.

(b)  Name three abiotic and three biotic components are seen in the picture.

A. The living things that affect an organism are called biotic factors like fish, tortoise, frog. Those things that are not alive are called abiotic factors like temperature, oxygen and carbon dioxide dissolved in the water, minerals dissolved.

(c)  Name three animals seen here and use the names to construct a food chain.

A.  Plants ----> insects ------> frogs ------> Fish ------> Man

(d)  Name the principal source of energy which keeps the system alive.

A.  Solar energy.

(e)  State the ecological role of plants seen here.

A. Solar energy enters the ecosystem mainly through green plants, and also through some kinds of bacteria and algae which are called producers. During the photosynthesis process, green plants use the energy of sunlight along with carbon dioxide and water to produce carbohydrates which we may call food. Photosynthesis produces oxygen as a by-product. To carry on photosynthesis and make food, green plants need not only sunlight, water, and carbon dioxide, but also small amounts of some minerals such as calcium, potassium, and magnesium which is available in dissolved form in the water.

Photosynthesis:

Carbon dioxide + water + solar energy + minerals + food + oxygen

(f)  What happens to the dead bodies and wastes of the organisms seen here? 

A.  Green plants are called producers because they produce their own food. Plants live and die, they may be eaten up by animals who also eventually die. There are organisms - the decomposers which act on dead plants and animals and for their existence. The dead bodies of plants & animals are principal source of food for these decomposers. The decomposers, such as bacteria, fungi and worms, convert the dead bodies of the plants and animals back to their elementary forms.