Aartee Mishra is teaching live on Unacademy Plus
Environment Book Summary Presented B Aartee Mishra
CHAPTER 1 ECOLOGY (Part -2)
Eco-System It is defined as a structural and functional unit of biosphere consisting of community of living beings and the physical environment, both interacting and exchanging materials between them. An Ecosystem is a complex set of relationship among the living resources, habitats, and residents of an area. It includes-plants, trees, animals, fish, birds, micro-organisms water, soil, and people When an ecosystem is healthy (i.e. sustainable) it means that all the elements live in balance and are capable of reproducing themselves. Ecosystem can be as small as a single tree or as large as entire forest. Components of Ecowstftne ecosystem is categorised c . The components of the ecosystem is categorised into abiotic of non- living and biotic of living components. Both the components of ecosystem and environment are same.
1. Abiotic Components . Abiotic components are the inorganic and nonliving parts of the world. The abiotic part consists of soil, water, air, and light energy etc. It also involves a large number of chemicals like oxygen, nitrogen etc. and physical processes including volcanoes, earthquakes, floods, forest fires, climates, and weather conditions. Abiotic factors Energy Energy from the sun is essential for maintenance of life. In the case of plants, the sun directly supplies the necessary energy. Rainfall Water is essential for all living beings. Majority of biochemical reactions take place in an aqueous medium
Temperature Temperature is a critical factor of the environment which greatly influences survival of organisms. Organisms can tolerate only a certain range of temperature and humidity. Atmosphere The earth's atmosphere is responsible for creating conditions suitable for the existence of a healthy biosphere on this planet. It is made up of 21 % oxygen, 78% nitrogen 0.038% carbon dioxide, and other inert gases (0.93% Argon, Neon etc) . Substratum Land is covered by soil and a wide variety of microbes, protozoa, fungi and small animals (invertebrates) thrive in it. Roots of plants pierce through the soil to tap water and nutrients.
Organisms can be terrestrial or aquatic. Terrestrial animals live on land. Aquatic plants, animals and microbes live in fresh water as well as in the sea. Some microbes live even in hot water vents under the sea. Materials: (i) Organic compound_such as proteins, carbohydrates, lipids, humic substances are formed from inorganic compound on decomposition. i Inorganic_compound such as carbon, carbon dioxide, water, sulphur, nitrates, phosphates, and ions of various metals are essential for organisms to survive. Latitude and altitude Latitude has a strong influence on an area's temperature, resulting in change of climates such as polar tropical, and temperate. These climates determine different natural biomes.
As the altitude increases, the air becomes colder and drier, affecting wild life accordingly . Biotic Components .Biotic components include living organisms comprising plants, animals and microbes and are classified according to their functional attributes into producers and consumers. s- Autotrophs (self nourshinnd certain bacteria and Primary producers are basically green plants (and certain bacteria and algae) They synthesise carbohydrate from simple inorganic raw materials like carbon dioxide and water in the presence of sunlight by the process of photosynthesis for themselves, and supply indirectly to other non- producers. .
The Flow of Energy Through Ecosystems Producers, Consumers, and Decomposers Energy dispersed as heat Energy from Producers Food CONSUMER To Consumers Energy dispersed as heat CONSUMER Energy dispersed as heat dispeysed And finally to Energy as heat Plant litter, wastes and dead bodies Decomposers PRODUCER DECOMPOSER
Consumers - Heterotrophs or phagotrophs (other nourishing) .Consumers are incapable of producing their own food (photosynthesis). They depend on organic food derived from plants, animals or both. Consumers can be divided into two broad groups namely micro and macro consumers. 1. Macro consumers_They feed on plants or animals or both and are categorised on the basis of their food sources. Herbivores are primary consumers which feed mainly on plants e.g. cow, rabbit. . Secondary consumers feed on primary consumers e.g. wolves. )- Carnivores which feed on secondary consumers are called tertiary consumers e.g. lions which can eat wolves. Omnivores are organisms which consume both plants and animals e.g. man.
Energy flow and trophic levels tertiary consumers 10 kcal eagle at losS secondary consumers 100 kcal snake primary consumers 1,000 kcal rabbit energy from Sun heat loss producers 10,000 kcal
Aquatic Biomes . Freshwater Lakes and Ponds Streams and Rivers - Marshes and Swamps Marine - Oceans Coastal wetlands
Ecotone is a zone of junction between two or more diverse ecosystems. For e.g. the mangrove forests represent an ecotone between marine and terrestrial ecosystem. Other examples are - grassland, estuary and river bank Grass Land Forest Characteristics of Ecotone Ecotone It may be very narrow or quite wide has conditions intermediate to the adjacent ecosystems. Hence it is a zone of tension. It is linear as it shows progressive increase in species composition of one in coming community and a simultaneous decrease in species of the other out going adjoining community. A well developed ecotones contain some organisms which are entirely different from that of the adjoining communities.