CBSE Class 10 Science Chapter 15 Our Environment Notes||class 10 science notes

  CBSE  CLASS 10   SCIENCE 

OUR ENVIRONMENT

TOPICS TO BE COVERED

• WHAT IS ENVIRONMENT 
• ECOSYSTEM AND IT'S COMPONENTS
• TYPES OF ECOSYSTEM
• COMPONENTS OF ECOSYSTEM
• FOOD CHAIN
• TROPHIC LEVELS
• ENERGY FLOW (10%law)
• FOOD WEB
• ENVIRONMENTAL PROBLEM
• MANAGING THE GARBAGE

ENVIRONMENT-

• Everything which surrounds and influence the organism directly or indirectly is included in the environment.

ECOSYSTEM AND ITS COMPONENTS-

Ecosystem-It is a system that include the interaction between abiotic and biotic things in the environment.

• Ecology-It is the study of inter relationship of organism between the biotic and abiotic components of the environment.
• Ecosystem-Termed coined by {Earnest Haekel}

Features of ecosystem-

• It is the structural  and functional unit of biosphere.
• It has the property of self perputation.
• It may be small or large.

Types of Ecosystem-

1. NATURAL ECOSYSTEM-

• It is a ecosystem that exist naturally and without the help of human support.
• It include-Aquatic[Desert,Grassland,Forest] and Terrestrial[marine, fresh water,lakes etc.]

      2.ARTIFICAL ECOSYSTEM-

• It is a ecosystem which is created and maintained by human beings.
• It incllude-[Crop field, Aquarium,Garden].

Components of Ecosystem-

1. BIOTIC COMPONENTS-

• These include all the living organism present in the environment i.e plants, animals, micro organisms.

-On the basis of food they consume the different living organism can be categorised into 3 groups these groups are-

1. PRODUCERS-All the green plants and certain blue green algae which can produce food by the process of photosynthesis are known as producers.eg  Autotrophs.
2. CONSUMER-These are the organisms which can depend on the producer for their nutrition in food.e.g Heterotrophs. The consumer can be further divided into-

          

• Herbivores.
• Carnivores.
• Parasite.
• Omnivores.

3. DECOMPOSER-These are the microorganism which feed on decaying and dead organic matter and convert it into simpler substance.e.g bacteria and fungi.

@Importance of decomposer in environment

• They decompose the dead bodies of animals and plants,thus act as a cleaning agent for the environment.
• The balance the nitrogen cycle.
• They help in recycling the materials in the biosphere.
• If there were no decomposer there would be a heep of that organism and due to this all the environment will be polluted.

2.ABIOTIC COMPONENTS-

• The abiotic components of an ecosystem are the non living components on which living organism depend. This component are light temperature water atmospheric gases wind etc.

FOOD CHAIN

• It is a sequence of organism through which energy is transferred in the form of food by the process of one organism consuming the other.
•  It always start from producers.

Characteristics of food chain-

• It is producer based chain.
• In the food chain there is a  unidirectional flow of energy.
• Food chain runs straight.
•  The food chain have generally 3-4 trophic levels.

Types of food chain

• Terrestrial Food Chain

- Green Plants → Deer → Lion

•  Aquatic Food Chain

- Aquatic Plants → Zooplankton → Small Fish → Large Fish

Significance of food chain

• It means of transfer of food from one tropic level to other.
• It provide information about the ecosystem.
• it help in understanding the interaction between organisms of an ecosystem.
• it is the pathway of flow of energy in any ecosystem.

Tropic level

It is defined as each step for level of food chain.

The different trophic levels are –

• Producers (T1)
• Primary consumers (herbivores-T2)
• Secondary consumers (primary carnivores -T2)
• Tertiary consumers(Sec carnivores -T3)
• Quaternary consumers (Ter. carnivores T4)
• Decomposers

Food web.

• The network of large number of food chain existing in an ecosystem are known as food web.
• Is formed by interconnections of different food chain

Difference between food chain and food Web

Energy flow 

• according to this law transfer of energy from one tropic level to another topic level never be 100%
• It is so because the most of the energy get lost as heat in the environment in  each transfer.
• On average about 10% of energy can be taken to the next topic level.
• the energy at available at each topic level gets diminished progressly due to loss of energy at each level.
• the flow of energy is uniditional that is the energy which passes to the next topic like dus not come back to the low tropic level.

Biological magnification

• The phenomenon of accumulation of maximum concentration of various chemicals in the body of an organisms through each trophic level is known as biological magnification or bio magnification.

Environmental problems

Depletion of ozone layer

• Ozone-it is a layer in the atmosphere where the ozone gas is concentrated.
• It is depleted by the ultraviolet radiation come from the sun.

Formation of ozone layer-

• Ozone is a product of UV radiation acting on Oxygen molecule,the high energy UV radiation split apart some molecular oxygen into free oxygen atoms these oxygen atom are very reactive and combine with molecular oxygen to form ozone.

Causes of ozone depletion

• Uses of harmful gases like chlorofluorocarbon.
• Increases in the air pollution.

Effect of ozone depletion

• UV radiation  causes skin cancer.
• These cause to damage eyes and also cause cataract disease in the eyes.
• Due to ulteravoilet radiation the immune system of body in decreases.
• It also affect the growth of animal and plants.

Ways to protect ozone layer

• Avoiding the use of chlorofluorocarbon gases.
• Minimising the use of vehicles to avoid pollution.
• Use of Eco friendly cleaning products.
• Use of network oxides should be prohibited.
• Awareness about the depletion of ozone layer.

Managing the garbage

• The household waste is called garbage.,Every household produces a lot of garbage on daily basis.

These waste substances can be divided into main group:-

• Biodegradable substances-the substances which can be disposed of naturally by the action of microorganism like bacteria fungi etc are called biodegradable substances.e.g leaves fruits waste paper etc
• Non biodegradable substances-the substances which cannot be converted into harmless simpler substance by the action of microorganisms are known as non biodegradable substances.these are toxes harmful maybe inert and accumulate in the environment of food chain.e.g plastic insecticides metals etc

Methods of waste disposal

1. Recycling-it is a processing of waste material to form a new product.
2. Composting-by degradable domestic waste can be buried in a pit dug into a ground and converted into compost and used as manual.
3. Incineration-it is a burning of a substance at high temperature to form as it is commonly used disposed hospital waste.
4. Landfills-solid waste is dumped into a low lying area and covered with soil.
5. Sewage treatment-ornate material in the sewage is allowed to settle down and decompose in a large tank.
6. Biogas production-in some places sewage is decomposed and anaerobically  to yield biogas and manure.

By YATENDRA KUMAR 

VECTOR STUDIES