OUR ENVIRONMENT class 10 presentation full lesson explained
- 2. ECO-SYSTEM AND ITS COMPONENTS FOOD CHAINS AND WEBS HOW DO OUR ACTIVITIES AFFECT THE ENVIRONMENT? OZONE LAYER AND ITS DEPLETION MANAGING OUR GARBAGE PRODUCTION OVERVIEW Today's Agenda
- 3. ECOSYSTEMS An ecosystem is a self-contained unit of living things (plants, animals and decomposers), and their non-living environment (soil, air and water). The examples of ecosystems are grassland (meadow), a forest, a desert, a mountain, a pond, a lake, a river and a sea. Most of the ecosystem in the world are natural ecosystems but some of them are also man-made ecosystems or artificial ecosystems. Artificial ecosystem includes crop-fields (agriculture lands), parks and aquarium. 1. 2. 3. 4.
- 4. A POND IS AN ECOSYSTEM Can anyone give me an answer why? Ponds are water bodies that are shallow, hence sunlight reaches till the bottom facilitating plant growth there. It offers components of a good ecosystem such as biotic factors (aquatic insects, fishes, phytoplanktons and microbes) as well as abiotic factors (water, soil, air, light, etc).
- 6. ABIOTIC COMPONENTS The abiotic components (or non-living components) of an ecosystem include the physical environment like soil, water and air alongwith the inorganic substances like carbon dioxide, nitrogen, oxygen, water, phosphorus, sulphur, sodium, potassium, calcium and other elements present in them. The physical factors or climate factors like light, temperature, pressure and humidity are also considered abiotic components of the ecosystem.
- 7. The biotic components (or living components) of an ecosystem is a community of organisms (like plants and animals), which is made up of many different inter-dependent populations. The biotic community (or living world) of an ecosystem includes three types of organisms:- Producer organisms (or Autotrophs) Consumer organisms (or Heterotrophs) Decomposers (or Saprotrophs) 1. 2. 3. BIOTIC COMPONENTS
- 8. Ecosystem functions as a self-sufficient or independent unit in nature. Ecosystem has both living and non-living components. All these components make the ecosystem functions as follows: From the nutrient pool of the earth (soil, water and air), carbon dioxide and water are absorbed by the producer organism (green plants). With the help of sunlight energy, the producer organisms convert these inorganic substances into organic compounds like carbohydrates which act as a food. Thus, producers trap the solar energy and then provide the basic food or energy for all other life forms in the ecosystem. The consumers (animals) derive their energy needs, directly or indirectly, from the producers (plants). When the producers (plants) and consumers (animals) die, then the decomposer organisms act on their dead bodies to return the various elements back to the nutrient pool (soil, water and air). Thus, an ecosystem involves input of energy and matter which are exchanged between living and non-living components in a cyclic process. FUNCTIONING OF ECOSYSTEM
- 9. Let's Discuss and Analyze Together
- 10. Producers are the organisms which can prepare their own food from simple inorganic substances like carbon dioxide and water by using sunlight energy in the presence of chlorophyll. The examples of producers are green plants and certain blue-green algae. PRODUCERS
- 11. Those organisms which consume food prepared by producers are called consumers. All the animals are consumers. If an animal eats grass or other green plants or their products itself we say that it gets the food from producers directly. If an animal eats the meat of another animal (which eats grass), then we say that it gets the food from producer indirectly. Consumers can be further classified as herbivores, carnivores and omnivores. CONSUMERS
- 12. Herbivores feed directly on plants. Herbivores are primary consumers. The herbivores may eat grasses, leaves, grains, fruits or the bark of trees. (Deer, Elephant, Squirrel) Carnivores feed on the flesh of animals. Those animals which eat only other animals as food are called carnivores. The carnivores eat the meat (or flesh) of other animals. (Lion, Tiger, Vulture) Those animals which eat both, plants and animals, are called omnivores. Man is called an omnivore because he eats both, plant food (such as grains, pulses, fruits and vegetables) as well as meat of animals (such as goat, chicken and fish). HERBIVORES, CARNIVORES AND OMNIVORES
- 13. Planktons are very minute or microscopic organisms freely floating don the surface of water in a pond, lake, river or ocean. Planktons are of two types: Phytoplankton and Zooplanktons. The microscopic aquatic plants freely floating on the surface of water are called phytoplanktons. Eg: Algae The microscopic aquatic animals freely floating on water are called zooplanktons. Eg: Protozoa PLANKTON
- 14. DECOMPOSERS The micro-organisms which break down the complex organic compounds present in dead organisms like dead plants and animals and their products like faeces, urine, etc., into simpler substances are called decomposers. The bacteria and fungi act as decomposers by the secretions of their body surfaces which decompose the organic matter present in dead plants and animals into simpler substances and liberate ammonia, carbon dioxide, etc.. The bacteria which act as decomposers are called putrefying bacteria. Decomposers help in the recycling of materials in ecosystem. The decomposers are also known as micro-consumers or Saprotrophs.
- 15. DO YOU HAVE QUESTIONS SO FAR? Feel free to make this an open discussion for questions or clarifications before proceeding.
- 16. Food chains and webs A food chain is the flow of food energy from one organism to the next and to the next and so on. They usually start with a producer (plants) and end with a carnivore. In a food chain an organism gets food from one group of organisms. What is a food chain?
- 17. Food chains and webs
- 18. Features of food chain Producers based : All sustainable food chains are producer based. Energy : Producers obtain energy from sun. All others (consumers) obtain the energy from food originally built up producers. There is unidirectional flow of energy. Biogenetic Nutrients : Inorganic nutrients must keep on circulating with the help of decomposers. Otherwise, food chains cannot be sustained. Straight : Unless linked with another, food chain runs straight. Size : Food chains are generally short with 3-5 trophic levels. Populations : Size of populations decreases with the rise in trophic level. Top carnivores are always very few. Operation at different trophic levels : An organism can operate at more than one trophic level, e.g., snake feeds on herbivorous rat as well as carnivorous frog.
- 19. Importance of food chain Food chains provide pathway for passage of food and energy distribution . They provide information about the living components of the ecosystem Food chain indicates the interactions and interdependence among the different organisms. The effect of reduction or or increase in the population at a trophic level can be known.
- 20. Food Webs Food web is a connection of several interconnected food chains. In a food web an organism gets food from more than one group of organisms.
- 21. Features of food Webs It doesn’t allow any population to starve. It does not allow species to grow as an increased availability. It doesn’t allow any species to overgrow. It allows endangered population to grow in size. It provides stability to ecosystem.
- 22. Each step in a food chain where transfer of food energy takes place is called trophic level. The first trophic level consists of producers. The second trophic level consists of primary consumers. The third trophic level consists of secondary consumers. The fourth trophic level consists of tertiary consumers. Since the transfer of food energy decreases at every trophic level, the number of trophic levels are limited and do not exceed four or five. Trophic levels :-
- 23. Green plants (producers) absorb about 1% of solar energy falling on the leaves and stores it as food energy during photosynthesis. During the transfer of food energy from one trophic level to the next, 90% of the energy is lost to the environment and only 10% is transferred to the next trophic level. So there is a decrease in the amount of food energy transferred at every trophic level by 10%. This is known as the 10% law. Energy Flow In Trophic levels :-
- 24. Harmful chemicals like insecticides and pesticides which are used to protect crops from insects and pests are absorbed by plants and enter the food chain. Since these chemicals are non biodegradable, they get accumulated at every trophic level and their concentration increases. Since human beings occupy the highest trophic level, the concentration of these harmful chemicals is maximum in our bodies. The increase in concentration of harmful chemicals in the bodies of organisms at higher trophic levels is called biological magnification. Biological magnification (Biomagnification) :-
- 25. DO YOU HAVE QUESTIONS SO FAR? Feel free to make this an open discussion for questions or clarifications before proceeding.
- 26. HUMAN ACTIVITIES AFFECT THE ENVIRONMENT Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Changes like these have triggered climate change, soil erosion, poor air quality, and undrinkable water. These negative impacts can affect human behavior and can prompt mass migrations or battles over clean water. We shall be looking at two of the environmental problems in detail, that is, depletion of the ozone layer and waste disposal.
- 27. Ozone molecule contains three oxygen atoms (O3). At higher levels in the atmosphere the UV radiation splits some oxygen molecules (O2) into free oxygen atoms which combines with oxygen molecules (O2) to form ozone. It is highly poisonous. Depletion of ozone layer in the atmosphere :- The ozone layer present in the higher layer of the atmosphere protects the earth from the harmful UV radiation from the sun. UV radiation causes skin cancer in humans. The ozone layer is being damaged by the use of chemicals like chloro fluoro carbons (CFCs) used in refrigerators and fire extinguishers. So the use of CFCs is now being reduced to protect the ozone layer.
- 29. i) Land fills ii) Recycling iii) Production of biogas and manure iv) Preparation of compost v) Incineration vi) Sewage treatment The household waste is called garbage. Some of the garbage is biodegradable and some are non biodegradable. Garbage causes pollution of air, water and soil. So it should be disposed properly. Some of the methods of garbage disposal are :- Managing the garbage we produce :-
- 31. A biodegradable material can be defined as a material which can be decomposed by bacteria or other natural organisms and not be adding to pollution. Biodegradable wastes are such waste materials which are and can be degraded by natural factors like microbes (e.g. bacteria, fungi and few more), abiotic elements like temperature, UV, oxygen, etc. Some examples of such wastes are food materials, kitchen wastes, and other natural wastes. A Non-Biodegradable material can be defined as a kind of substance which cannot be broken down by natural organisms and acts as a source of pollution. Unlike biodegradable wastes, non-biodegradable cannot be easily handled. Non- biodegradable wastes are those who cannot be decomposed or dissolved by natural agents. They remain on earth for thousands of years without any degradation. A notable example is the plastics which are a commonly used material in almost every field. To give these plastics a long lasting effect, improved quality plastics are being put to use. This made them more temperature resistant and more durable even after use. Other examples are cans, metals, and chemicals for agricultural and industrial purposes.
- 32. Improvements in our life-style have resulted in greater amounts of waste material generation. Changes in attitude also have a role to play, with more and more things we use becoming disposable. Changes in packaging have resulted in much of our waste becoming nonbiodegradable. How has that impacted our environment? Class Discussion
- 33. RECAP OF TODAY'S CLASS The various components of an ecosystem are interdependent. The producers make the energy from sunlight available to the rest of the ecosystem. There is a loss of energy as we go from one trophic level to the next, this limits the number of trophic levels in a food-chain. Human activities have an impact on the environment. he use of chemicals like CFCs has endangered the ozone layer. Since the ozone layer protects against the ultraviolet radiation from the Sun, this could damage the environment. The waste we generate may be biodegradable or non-biodegradable. The disposal of the waste we generate is causing serious environmental problems.
- 34. THANK YOU! Done By Ishani Vishwanathan