Our Environment Class 10 Chapter 15 Notes
Our Environment (Class 10) is a very important chapter in your class’s 10th science syllabus. You can score very good marks in this chapter as this is easy compared to other chapters. Here, we have provided details on class 10 Our Environment Science Notes.
The environment includes all those effects and a set of conditions that impact the life of an organism like their growth, survival, evolution, and reproduction. Thus, our environment is composed of the physical surroundings, living beings, and climatic provisions of the region. All these factors interact with one another, to conserve the balance of the environment. Still, this balance is being disturbed by various human exertion.
Waste varieties and Their Effects on Our Environment
The unusable, left-over, or discarded substances are called waste substances. Improper operation of waste generated by various exercises leads to environmental imbalance.
Waste is of three types, i.e. solid (household wastes, farm wastes, industrial wastes, etc.), liquid (chemical wastes), and gaseous (smoke from chimney and automobiles, etc) wastes.
These waste substances can be broken up into two main groups
1. Biodegradable substances
2. Non-biodegradable substances
The essences which can be deposed of naturally by the act of microorganisms like bacteria, fungi, etc are called biodegradable substances. These organisms secrete an enzyme that causes the crack-up of biodegradable substances into simple forms.
Biodegradable waste can also be deposed to treatment by waste operation plants. They can be used as manure or compost to accelerate soil fertility, e.g. garbage, sewage, livestock waste, used tea leaves, waste papers, left-over food papers, etc.
Effects of Biodegradable Substances
They perform as pollutants only when their quantity becomes large. The effects of biodegradable essences are as follows-
• Decomposition of biodegradable wastes leads to foul odour.
• discarding industrial wastes reduces the fertility of the soil and leads to a reduction in crop yields.
• Breeding of flies in huge amounts on these wastes carries germs and spreads diseases.
• blowing off waste into water bodies leads to water contamination. This results in the bedspread of varied water-borne diseases.
The substances that cannot be converted into harmless simpler forms by the act of microorganisms are called biodegradable substances.
These are poisonous, dangerous, maybe inert, and accumulate in the environment.
These count for the significant pollutants of the environment. Most biodegradable wastes result from human exercise, e.g. radioactive wastes, plastic, germicides, heavy metals such as lead, arsenic, aluminium, etc.
Effects Of Non-Biodegradable Substances
The effects of non-biodegradable substances are as follows:
• Substances like radioactive wastes, lead, mercury, etc. accumulate in the environment and cause life-threatening conditions in humans and diverse living beings.
• They contaminate water and damage aquatic plants and creatures.
The ecosystem is considered the structural and functional unit of the biosphere. It’s a firm ecological unit where constant input of energy and circulation of matter takes place.
The term ecosystem was first minted by AG Tansley in 1935. All the interacting organisms in an area together with the-living members (abiotic factors) of the environment formal ecosystem, e.g., a lake, a field, or timber.
Types of Ecosystem
These are of two types:
1. Natural Ecosystem
The naturally being ecosystem without any human support is called a natural ecosystem. Depending upon the habitats, the natural ecosystem may be terrestrial (desert, grassland, and forest) and aquatic (ponds, lakes, arms, and marine).
2. Artificial Ecosystem
An ecosystem that’s created and conserved by humans is called an artificial or man-made ecosystem. These calculate on human labours to sustain. It doesn’t possess a self-regulating medium.
Agro-ecosystem is the largest man-made ecosystem. Other examples are aquariums, botanical auditoriums, parks, field crops, etc.
Biotic components contain all the living organisms present in the ecosystem, i.e. plants, creatures, and microorganisms.
The living organisms are connected by various mechanisms and exhibit interdependence on each other. These are initially classified into different groups grounded on their nutritive relationships.
Based on the food they eat, the distinct living organisms can be categorized into three groups:
These groups are as follows
All green plants and certain blue-green algae which can deliver food by the process of photosynthesis are producers. These are also called autotrophs.
They absorb the radiant energy of the sun and deliver organic compounds ( i.e. carbohydrates). They convert solar energy into chemical energy and are therefore called autotrophic, e.g. plants and blue-green algae.
These are the cradle of nutrition for the rest of the ecosystem. They take up CO2 and discharge oxygen in turn into the environment, therefore, balancing the composition of air.
They’re dependent on producers for their nutritive requirements and consume food prepared by producers. They’re, therefore, called heterotrophs.
Consumers can be further divided into the following three kinds:
- Herbivores – These are primary or first-order consumers who feed directly on the producers, i.e. plants. e.g. grazing animals like zebra, goat, horse, lamb, etc.
- Carnivores – These are the creatures that feed on other creatures. The herbivores which feed on herbivores are called second-order consumers. Some herbivores may be predators (like lions, hawks, and wolves which assault and kill their prey and feed on their masses). Some may be scavengers (like jackals that feed on breathless animals that they find). These are called third-order consumers.
- Omnivores – These are creatures that feed on both plants and animals. e.g. humans and bears.
These are microorganisms that cater to decaying and breathless organic matter. They break down the remains of dead creatures and plants, to releases varied substances that then be utilized by other members of the ecosystem, e.g. bacteria and fungi.
They’re useful in breaking down waste from the ecosystem. They assist in recycling materials, cleaning waste, and creating a place for the growth of new organisms.
The abiotic factors of an ecosystem are the non-living factors on which living organisms are dependent. Each abiotic element influences the number and variety of plants and creatures present in an ecosystem. This in turn influences the biodiversity of a region.
These factors are light, temperature, water, atmospheric gases, wind, etc. They’re presented below in detail.
- Light – Light energy (sunlight) is the primary cradle of energy in nearly all ecosystems. It’s used by green plants (which contain chlorophyll). During photosynthesis, plants produce organic substances by linking inorganic substances.
- Temperature – The allocation of plants and creatures is greatly influenced by extremes in temperature. The pattern of rain also affects the growth of the plant. This plant growth determines the general variety of animals dwelling in that place.
- Atmospheric gases – Oxygen is needed for respiration and carbon dioxide for photosynthesis. Nitrogen is made available to plants by given bacteria and through the act of lightning.
- Wind – It helps in pollination and germ dispersal of some plants. It can put off and redistribute top soil, especially where vegetation has been degraded.
- Water – Water is must-have for life. Plant and animal habitats differ from entirely aquatic environments to very droughty deserts.
The transfer of food or energy takes place through varied paths or levels in the food chain known as trophic levels. The producers (autotrophs) are extant at the first trophic level. They set up solar energy, making it attainable for consumers (heterotrophs).
The herbivores or the direct consumers constitute the second trophic degree. Small carnivores or secondary consumers are extant at the third trophic level. The big or the tertiary consumers crystallize the fourth trophic level.
It’s a direct network of living organisms in a community through which energy is conveyed in the form of food. It describes the connection of organisms about who eats whom’. It displayed as a series of branching lines hence, creating a food web.
Types of Food Chains
The option of habitat classifies food chains into two types:
- Terrestrial food chain-It’s the food chain present on the land.
e.g. Grass → Insects → Snake Hawk.
2. Aquatic food chain-It’s the food chain in different water bodies.
e.g. Phytoplankton Zooplankton → Fish → Shark.
Significance of Food Chain
- Food chain involves the transfer of energy, accouterments, and nutrients. The organisms of the food chain serve as the agents for the transfer of energy from one level to another.
- The knowledge of the food chain helps in understanding the feeding relationship as well as the interaction between organisms and the ecosystem.
- In extension to the above points, it also helps to understand the movement of toxic substances and the challenges associated with biological magnification in the ecosystem.
It’s the connection of distinct food chains, which relate at various trophic levels handling in an ecosystem. Each organism is typically consumed by two or more distinct kinds of organisms. They in turn are consumed by several other organisms. So, rather than a straight line, the relationship is shown as a series of branching lines hence, creating a food web.
Energy is accumulated by the primary producers and is conveyed through the food chain to distinct trophic levels. This phenomenon is called energy flow.
It’s unidirectional and there’s no recycling to the former level. Whenever energy is conveyed from one configuration or from one network to another, some energy is always lost. The inflow of energy in an ecosystem can be derived in the following steps:
- The green plants in a terrestrial ecosystem capture about 1% of the energy of sunlight (chemical). They convert it into food energy.
- The green plants are consumed by primary consumers. Due to this a major amount of energy is misplaced as heat. Some volume goes into digestion and in doing composition and rest goes towards excrescence and reproduction.
- Thus, 10% can be grasped as the mean valuation for the amount of organic matter that’s extant at each step and reaches the next trophic position.
- Since, only a little energy is available for the succeeding level of consumers, food chains generally correspond of three or four steps. The loss of energy at each step is veritably large. So, little usable energy is left after four trophic levels.
It’s the phenomenon of a progressive increase in the attention of non-biodegradable toxicants in organisms at each consecutive trophic level.
Causes of Biomagnification
Harmful chemicals and pesticides like DDT, etc., are sprayed on crop plants to cover them from pests and diseases. These chemicals either wash down into the soil or water bodies.
From the soil, these are soaked by plants and from water bodies, these are grasped by aquatic plants and creatures. This is why our food grains, similar to wheat, rice, fruits, and vegetables hold varying amounts of pesticides leftovers. In this manner, poisonous chemicals penetrate the food chain.
As these chemicals are non-biodegradable, they get collected in organisms’ bodies. Their attention keeps on adding at each trophic level. The maximum attention of these chemicals gets accumulated in the human body. This is because they occupy the topmost point in any food chain.
Human Impact On The Natural Environment
Humans are an essential part of the environmental variation in the environment. Any variation in the environment also affects us. Various human conditioning contaminates the environment in varied ways and poses serious environmental threats.
E.g. Depletion of layer, waste accumulation, etc.
Ozone (03) is a molecule formed by three oxygen atoms and is a fatal poison. It’s found in the stratosphere, i.e. 20-30 km above the planet.
Due to environmental pollution, the ozone layer has commenced depleting in the 1980s.
This was substantially due to the accelerating use of man-made chemicals like Chlorofluorocarbons (CFCs). These are utilized in refrigerants as coolants and fire extinguishers.
CFCs are veritably stable. They’re found to persevere in the atmosphere. Being stable, they don’t degrade handily and rise high over in the atmosphere. In the atmosphere, UV radiations breakdown CFCs molecules and release chlorine atoms. These atoms responding with ozone, disconnect ozone molecules into oxygen.
Therefore, decreasing the volume of ozone results in the depletion of the ozone layer. An illustration of ozone layer depletion can be observed in Antarctica.
Significance Of Ozone Layer
The layer of the atmosphere in which the utmost of the atmosphere’s ozone is condensed is called the ozone layer. It shields the exterior of the earth from dangerous ultraviolet (UV) radiation from the sun.
These radiations are largely dangerous to organisms. They can cause skin cancer in human beings, harm eyes (cause an ailment called a cataract), decrease crop yield, disturb global rainfall, etc.
Managing the Garbage
Household waste is called garbage. Every household produces a lot of garbage on a day-to-day base. Advancements in life have resulted in greater volumes of waste material production.
Methods of Waste Disposal
Garbage management trials include a system of disposing of garbage with the least effect on the environment.
Disposal of waste means to get free of waste. This trial should be done scientific way.
Originally the wastes should be separated as biodegradable or non-biodegradable and recyclable material. This enables the operation of proper disposal treatment.
There are various styles of waste disposal, some of them are:
1. Recycling – It’s the processing of waste materials to form substitute products. Materials like tin, barrels, metallic papers, rags, paper, glass, polythene, etc., are recyclable.
2. Composting – Biodegradable domestic wastes, similar to left-over food, fruit and vegetable peels, etc., can be buried in a hole, dug into the ground. They’re converted into compost and utilized as manure.
3. Incineration – It’s the burning of a material at high temperatures to form ash. It reduces the volume of waste vastly. It’s generally used to dispose of hospital waste.
4. Landfills – Solid waste is dumped into a low-lying region and covered with soil. A big landfill point can be utilized to dispose of waste materials for a substantial time.
5. Sewage treatment – Sewage is bored over to Sewage Treatment Plants (STPs). Then the sewage is filtered. Organic material in the sewage is permitted to settle down and decompose in bulky tanks. The water from these tanks is cleaned (filtered) and is then released into the water bodies.
Might be helpful for you :-
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I hope these notes for our environment (class 10) will help you understand the chapter better and you’ll perform well in your exams.
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