Environmental Science PDF - AECC 1 Unit 1 - Environment & Its Components

Environmental Science- I AECC 1 Environmental Science – (Part I): Unit 1: Environment & Its Components Dr. Papiya Majumdar Reference book: Dept. of Chemistry Erach Bharucha - Sister Nivedita University Environmental Studies...

Environmental Science- I AECC 1 Environmental Science – (Part I): Unit 1: Environment & Its Components Dr. Papiya Majumdar Reference book: Dept. of Chemistry Erach Bharucha - Sister Nivedita University Environmental Studies for Undergraduate courses - UGC Unit 1: THE MULTIDISCIPLINARY NATURE OF ENVIRONMENTAL STUDIES: Environment & Its Components 1.1 DEFINITION, SCOPE AND IMPORTANCE 1.1.1 Definition Environmental studies deals with every issue that affects an organism. It is essentially a multidisciplinary approach that brings about an appreciation of our natural world and human impacts on its integrity. It is an applied science as its seeks practical answers to making human civilization sustainable on the earth’s finite resources. 1.1.2 Scope As we look around at the area in which we live, we see that our surroundings were originally a natural landscape such as a forest, a river, a mountain, a desert, or a combination of these elements. Most of us live in landscapes that have been heavily modified by human beings, in villages, towns or cities. But even those of us who live in cities get our food supply from surrounding villages and these in turn are dependent on natural landscapes such as forests, grasslands, rivers, seashores, for resources such as water for agriculture, fuel wood, fodder, and fish. Thus our daily lives are linked with our surroundings and inevitably affects them. We use water to drink and for other day-to-day activities. We breathe air, we use resources from which food is made and we depend on the community of living plants and animals which form a web of life, of which we are also a part. Everything around us forms our environment and our lives depend on keeping its vital systems as intact as possible. 1.1.2 Scope…….contd…. Our dependence on nature is so great that we cannot continue to live without protecting the earth’s environmental resources. Thus most traditions refer to our environment as ‘Mother Nature’ and most traditional societies have learned that respecting nature is vital for their livelihoods. This has led to many cultural practices that helped traditional societies protect and preserve their natural resources. Respect for nature and all living creatures is not new to India. All our traditions are based on these values. Emperor Ashoka’s edict proclaimed that all forms of life are important for our well being inFourth Century BC. Over the past 200 years however, modern societies began to believe that easy answers to the question of producing more resources could be provided by means of technological innovations. For example, though growing more food by using fertilizers and pesticides, developing better strains of domestic animals and crops, irrigating farmland through mega dams and developing industry, led to rapid economic growth, the ill effects of this type of development,led to environmental degradation. 1.1.2 Scope…….contd…. The industrial development and intensive agriculture that provides the goods for our increasingly consumer oriented society uses up large amounts of natural resources such as water, minerals, petroleum products, wood, etc. Nonrenewable resources, such as minerals and oil are those which will be exhausted in the future if we continue to extract these without a thought for subsequent generations. Renew-able resources, such as timber and water, are those which can be used but can be regenerated by natural processes such as regrowth or rainfall. But these too will be depleted if we continue to use them faster than nature can replace them. For example, if the removal of timber and firewood from a forest is faster than the regrowth and regeneration of trees, it cannot replenish the supply. And loss of forest cover not only depletes the forest of its resources, such as timber and other non-wood products, but affect our water resources because an intact natural forest acts like a sponge which holds water and releases it slowly. Deforestation leads to floods in the monsoon and dry rivers oncethe rains are over. Our natural resources can be compared with money in a bank. If we use it rapidly, the capital will be reduced to zero. On the other hand, if we use only the interest, it can  What is Environment? Environment can be defined as a sum total of all the living and non-living elements and their effects that influence human life. While all living or biotic elements are animals, plants, forests, fisheries, and birds, non-living or abiotic elements include water, land, sunlight, rocks, and air. The natural environment or natural world encompasses all living and non-living things occurring naturally, meaning in this case not artificial. The term is most often applied to Earth or some parts of Earth. This environment encompasses the interaction of all living species, climate, weather and natural resources that affect human survival and economic activity. The concept of the natural environment can be distinguished as components: Complete ecological units that function as natural systems without massive civilized human intervention, including all vegetation, microorganisms, soils, rocks, the atmosphere, and natural phenomena that occur within their boundaries and their nature. Universal natural resources and physical phenomena that lack clear-cut boundaries, such as air, water, and climate, as well as energy, radiation, electric charge, and magnetism, not originating from civilized human actions. What is Geographical Distribution? the natural arrangement and apportionment of the various forms of animals and plants in the different regions and localities of the earth. What are the types of Geographic Distribution? There are mainly three types of geographic distribution, namely, cosmopolitan, endemic, and disjunct distribution. Cosmopolitan Distribution A species is said to be cosmopolitan if it can be found in almost all types of its appropriate habitat existing on the Earth. The cosmopolitan species of living organisms are extremely widespread, typically found on all continents and in different climates. Such a widespread geographic distribution of species is known as cosmopolitan distribution. The types of habitats of the cosmopolitan species include cities, rural settlements, mountains, islands, oceans, and others. In addition to different abiotic and biotic factors, the availability of abundant food resources, shelter, and other factors collectively result in the cosmopolitan distribution of a species. House mouse - These widespread mammalian species are found in appropriate habitats across the world, except in Antarctica, due to human travel. It is found in North America, South America, Oceania, Africa, Europe, and Asia. Some common examples of animals that have a cosmopolitan distribution are: Osprey - It is a large fish-eating bird of prey with a cosmopolitan distribution. Ospreys are found in temperate and tropical regions of all continents, except Antarctica. They can be found in various continents, namely Australia, North America, South America, Africa, Asia, and Europe. What is Endemic Species? Endemic species are those plants and animals that exist only in one geographical region. Species can be endemic to large or small areas of the world. Some may be endemic to the particular continent; some are endemic to a part of a continent, and others to a single island. Often an endemic species is confined to a certain area because they are highly adapted to the particular niche. They may eat only a certain type of plant that is found nowhere, or a plant is perfectly adapted to flourish in a very particular climate and soil type. Endemic distribution Endemism is a term used in biology to talk about the distribution of a taxon limited to a small geographic area and which can therefore be found naturally in this place. In consequence, endemic species are those that live in a limited area, such as a mountain range, lake or island, among others.  Some Key Examples of Endemic Animals across the World Nilgiri Blue Robin It is endangered and endemic to the shoal forest of southern India. This small passerine bird is found to occur only above 1200 m altitudes in high-altitude grasslands of Western Ghats.  Polar bear (Ursus maritimus): this carnivorous mammal lives in the polar region and in the frozen areas of the Northern Hemisphere. It is the only surviving super- predator in the Arctic. Panda: This mammal is typical of Asia, although it has become a symbol of China the country that has done most to save it from extinction.  Some Examples of Endemic Plants Sapria Himalayana - It is a root parasite plant that is reported from Arunachal Pradesh and also found in Meghalaya, Manipur, and Assam. Nepenthes Khasiana - Nepenthes Khasiana is a carnivorous plant which is located in the Khasi Hills of Meghalaya. It is a pitcher plant and it is believed that it is the only species of pitcher plant which is found in India.  Holgrem's buckwheat is endemic to Great Basin National Park, USA. Both the orange-breasted sunbird (Anthobaphes violacea) and the Kniphofia uvaria plant it feeds on are found exclusively in South Africa.  Endemic vs Native Species A native species is found in a certain ecosystem due to natural processes such as natural distribution. The koala, for example, is native to Australia. No human intervention brought a native species to the area or influenced its spread to that area. A native species is not necessarily restricted to its native area or the place of its origin. It may be found in other areas of the world as well. On the contrary, the endemic species is specific to a particular region and is found nowhere else. Disjunct distribution In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically. Disjunct distribution is also known as range fragmentation. Disjunct distribution occurs due to several reasons such as mountain formation, rise in sea level, and continental drift. Disjunct distribution can also occur due to the shifting or migration of the organism to new areas. Disjunct distribution can occur due to rafting or other animals transporting organisms to different places through migration. Other causes for disjunct distribution maybe due to flooding or changes in the flow of wind or due to introduction or foreign species accidentally or deliberately. Extinction of animals can also cause disjunct distribution.  Divisions of Environment 1. Atmosphere: The layer of air surrounding the earth at a height of around 1600 km and it consists of many gases is known as atmosphere. The major constituents of the atmosphere are nitrogen, oxygen and water vapor. The minor constituents are argon and carbon dioxide, the trace components include inert gases like methane. It gives Oxygen for human respiration (metabolic requirements). It gives Oxygen for wild fauna in natural ecosystems and domestic animals used by man as food. It provides Oxygen as a part of carbon dioxide, used for the growth of plants (in turn are used by man). Living creatures cannot survive without air even for a span of a few minutes. To continue to support life, air must be kept clean. Major pollutants of air are created by industrial units that release various gases such as carbon dioxide, carbon monoxide and toxic fumes into the air. Air is also polluted by burning fossil fuels. The buildup of carbon dioxide which is known as ‘greenhouse effect’ in the atmosphere is leading to current global warming. The growing number of scooters, motorcycles, cars, buses and trucks which run on fossil fuel (petrol and diesel) is a major cause of air pollution in cities and along highways. Air pollution leads to acute and chronic respiratory diseases such as various lung infections,  The atmosphere forms a protective shell over the earth: The exosphere (Ancient Greek: ἔξω éxō "outside, external, beyond") is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the density is so low that the molecules are essentially collision-less. The thermosphere is the fourth layer of the Earth's atmosphere that absorbs the sun's radiation, making it very hot. The thermosphere puts on the auroras, a dazzling light show caused by colliding particles, and the thermosphere is also where satellites orbit the Earth. It is characterized by high temperature and large variability, in response to changes in solar ultraviolet radiation and solar-driven geomagnetic activity. The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere. Within this layer of the atmosphere, ultraviolet radiation causes photoionization/photodissociation of molecules, creating ions; the thermosphere thus constitutes the larger part of the ionosphere. The mesosphere lies between the thermosphere and the stratosphere. “Meso” means middle, and this is the highest layer of the atmosphere in which the gases are all mixed up rather than being layered by their mass. The mesosphere is 35 kilometers thick The stratosphere is 50 kilometers thick and contains a layer of sulphates which is important for the formation of rain. It also contains a layer of ozone, which absorbs ultra-violet light known to cause cancer and without which, no life could exist on earth. The lowest layer of atmosphere, troposphere the only part warm enough for us to survive in, is only 12 kilometers thick.