Lakhmir Singh Manjit Kaur Class 10 Biology Ch 5 ‘Our Environment’ Inside Questions & Answers

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Inside Questions of Lakhmir Singh Manjit Kaur Class 10 Biology Chapter 5 ‘Our Environment’.

Board CBSE
Class 10
Subject Biology
Chapter Name Our Environment
Done by Sourav Saha (B.A., B.Ed.)

(1) What is called environment? What does it include?

Ans. The physical and biological world where we live is called our environment.

It includes our physical surroundings like air, water bodies, soil and all the organisms such as plants, animals, human beings and micro organisms like bacteria and fungi.

(2) Name one organisms in our environment who change the natural environment to fulfil their needs.

Ans. Human beings.

(3) Define Biodegradable wastes. Give example.

Ans. Those waste materials which can be broken down to non – poisonous substances in nature in due course of time by the action of micro organisms like certain bacteria are called biodegradable wastes.

Ex. Cattle dung, Compost, Animal bones, leather, tea leaves, wool paper, wheat, wood, hay etc.

(4) Define Non Biodegradable wastes. Give Example.

Ans. Those waste material which can not be broken down into non poisonous or harmless substance in nature are called non biodegradable wastes.

Ex. DDT, Plastics, Polythene bags, Synthetic fibre, Aluminium cans, Glass objects, Metal Articles etc.

(5) Why some materials are biodegradable whereas others are non biodegradable.

Ans. The micro organisms like bacteria and other decomposer organisms present in our environment are specific in their action. They breakdown the natural materials or products made from natural materials but do not break down man made materials such as Plastics. So it is due to the property of de4composer organisms of being specific in their action that some waste materials are biodegradable whereas others are non biodegradable.

(6) Why should we use paper, cotton, jute bags instead of plastic bags.

Ans. These is because they are biodegradable materials whereas plastic bags should be avoided because plastic is a non biodegradable material.

(7) How do living organisms interact with another?

Ans. Living organisms interact with another through their food chains in which one organism consume another organism.

(8) What is ecosystem. Examples.

Ans. An ecosystem is a self contained unit of living things and their non living environment.

Example: a grassland, a forest, a desert, a mountain, a pond, a lake, a river etc.

(9) Write some example of artificial ecosystem.

Ans. Crop fields, Gardens, Parks and aquarium.

(10) Explain about components of an ecosystem.

Ans. All the ecosystems are made up of 2 main components –

(i) Abiotic components

The abiotic components of an ecosystem include the physical environment like soil, water and air alongwith the inorganic substance like CO2 nitrogen, oxygen, water, phosphorus, sulphur, sodium, potassium.

The physical factors or climatic factors are also considered abiotic components of the ecosystem.

(ii) Biotic components

The biotic components of an ecosystem is a community of organisms which is made up of many different inter dependent populations.

The biotic community of an ecosystem includes three types of organisms name Autotrophs, Heterotrophs and Saprotrophs.

(11) What is Autotrophs? Give example.

Ans. Autotrophs also known as producer organisms. They synthesize their own food.

Ex. Green plants.

(12) What is Heterotrophs? Give example.

Ans. Consume organisms are also called Heterotrophs. They are depended on others for food.

Ex. Animals.

(13) What is Saprotrophs? Give example.

Ans. Decomposer organisms called Saprotrophs. They consume the dead remains of other organisms.

Ex. Bacteria, Fungi.

(14) Write the functioning of an ecosystem briefly.

Ans. From the nutrient pool of the earth, Carbon Di Oxide and water are absorbed by the producer organisms. With the help of sunlight energy the producer organisms convert these inorganic substance into organic compounds like carbohydrates which act as food. Thus producer trap the solar energy and then pro vide the basic food or energy for all other life forms in the ecosystem.

The consumer derived their energy needs directly or indirectly from producers. When producer and consumer die then the decomposer organisms act on their dead bodies to return the various elements back to the 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.

(15) Which are called producer in the living world?

Ans. Green plants.

(16) Write some example of common consumer organisms.

Ans. Some examples of common consumer organisms are – man, goat, deer, rfish, lion, cow, buffalo etc.

(17) In how many groups consumers can be divided? Explain.

Ans. Consumers can be divided into three groups –

(i) Herbivores:- Those animals which eat only plants are called herbivores.

Ex. Cow, Buffalo etc.

(ii) Carnivores: Those animals which eat only other animals as food are called carnivores.

Ex. Lion, Tiger etc.

(iii) Omnivores: Those animals which eat both plants and animals are called omnivores.

Ex. Man, Dog.

(18) What is called secondary consumer?

Ans. The small carnivores which feed on herbivores are called secondary consumer.

Example: Frog, Lizard, Bird etc.

(19) Define tertiary  consumer.

Ans. The large carnivores which feed upon the small carnivores are called tertiary consumers.

(20) What is called planktons?

Ans. Producers and consumers which are extremely small. These are called planktons.

(21) Name the two types of Planktons.

Ans. The two types of plankton are : Phytoplanktons, and Zooplanktons.

(22) What is called phytoplanktons?Give example.

Ans. The microscopic aquatic plants freely floating on the surface of water called phytoplanktons.

Ex. Algae.

(23) Define zooplanktons.

Ans. The microscopic aquatic animals freely floating on water are called zooplanktons.

Ex. Protozoa.

(24) Define Decomposer.

Ans. 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. Ex: Bacteria, Fungi.

(25) Write in short Importance of Decomposers.

Ans. The decomposers help in decomposing the dead bodies of plants and animals and hence act as cleansing agents of environment.

(26) Write one example that decomposer maintains the fertility of the soil.

Ans. The decomposers like putrefying bacteria and fungi decompose the dead plants and animals bodies into ammonia. This ammonia is converted into nitrates by the nitrifying bacteria present in soil. These nitrates act as fertilizer in the soil and are again absorbed by the plants for their growth.

Thus it is only due to the presence of decomposers that the various nutrient elements which are initially taken by the plants from the soil, air and water are returned to the soil, air and water after the death of plants and animals.

(27) What is food chain? Write one example.

Ans. The transfer of food or energy from one organism to another called food chain.

Ex. Grass —Deer —- Lion.

(28) Write an brief example to understand the meaning of food chain.

Ans. Suppose there is a field having a lot of green plants. Now plants can be eaten up by the rats. Therefore these rats can be eaten up by cats moreover cats can be eaten up by dogs. So we find that there is a sequence in which one organism eats up by other organism to fulfil its belly.

(29) Write one example of four step food chain.

Ans. Plants – Worms – Birds – Cats.

(30) Write one example of food chain operating in an aquatic ecosystem.

Ans. Algae – Protozoa – Small Fish – Big fish.

(31) What is called food web?

Ans. The inter connected food chains operating in an ecosystem which establish a network of relationships between various species is called food web.

(32) Define Trophic levels.

Ans. The various steps in a food chain at which the transfer of food takes place are called trophic levels.

(33) Write the various trophic levels in a food chain.

Ans. The various trophic level of food chain are:-

Producer – First trophic level.

Herbivores – Second trophic level.

Carnivores – Third trophic level.

Top Carnivores – Fourth trophic level.

(34) How Sahara desert are formed. Describe briefly.

Ans. When romans started capturing lions, the population of lion in the forest was reduce to a large extent. Lions is a predator which kills the herbivores animals like deer, sheep, goat, buffalo etc.

So when the population of lion decreased there was no one to kill these of herbivorous animals. Thus the number of herbivorous animals day by day increased and once they ate up all the vegetation in that region and turn lush green forests into vast desert called Sahara desert.

(35) Write the effect if all the lions are removed from the food chain.

Ans. If all the lions are removed from the chain therefore the number of herbivores animals (Deer, Buffalo, sheep, Goat etc) will increase rapidly and they will lead to excessive grazing of grass. The density of producers like grass will be very much reduced.

Overgrazing may even eliminate the grass and other green plants completely and turn lush green forest into a desert area having no vegetation at all.

(36) Write the effect if all the deer are removed from the food chain.

Ans. Deer is a food  for lion. If all the deer are removed from the forest, then there will be no food for the lions. SOME OF LIONS also will die to absence of food. In which the population of lion will decrease. The decrease of population lion also disturb other food chain in which lions operate.

The hungry lions of the forest can come out of the forest in search of food and may kill other domestic animals and humans.

(37) What we should remember about the transfer of energy in the ecosystem?

Ans. We should remember the following points-

(i) Energy is not created in the ecosystem. Energy is only converted form one form to another.

(ii) There is a continuous transfer of energy from one trophic level of organisms to the next trophic level in a food chain.

(iii) At each trophic level of organisms some of the energy is utilized by the organisms for their metabolic activities like respiration and for growth.

(38) Flow of material in Ecosystem is cyclic but flow of energy is unidirectional. Give reason.

Ans. The materials like water, carbon and nitrogen are taken up by the plants from the soil, air and water bodies etc. and made into food. This food is then passed on to the animals. Like herbivores and carnivores in a food chain. After the death and decay of plants and animals the materials like water, carbon and nitrogen present in their bodies returned to soil, air and water from where they taken originally. These materials can then be reused for the growth of new plants. In this way the materials are used in a cyclic manner. So the flow of materials like water, carbon and nitrogen etc in the ecosystem is said to be cyclic.

The flow of energy in the ecosystem is said to be unidirectional because the energy lost as heat from the living organisms of food chain can not be reused by plants in photosynthesis.

(39) Name the scientist who gave ten per cent law for energy transfers in food chains.

Ans. Raymond Lindeman.

(40) Describe about ten percent law.

Ans. According to ten percent law, only 10 percent of energy entering a particular trophic level of organisms is available for transfer to the next higher trophic level.

(41) Calculate the amount of energy available to lion in the following food chain if plants have 20000 J of energy available from the sun.

Plants —-.> Deer —–Lion

Ans. Plants can trap only 1 percent of the sun’s energy falling on them. Now 1/100 x 20000 is 200 J,. so the plants have actually 200 J of energy available in them as food.

The plants are eaten up by deer. Now according to 10% law 10/100 x 200 J = 20 J of energy will be available in deer as flesh food.

The deer will transfer 10/100 x 20 J = 2 J of energy to the lion.

(42) Why the number of trophic levels in a food chain is limited?

Ans. This is because afterthat the energy available for the next organism will be so small that it will be insufficient to sustain  the life of that organism.

(43) What is called biological magnification?

Ans. The increase in concentration of harmful chemical substances like pesticides in the body of living organisms at each trophic level of a food chain known as biological magnification.

(44) Which of the following will have the maximum concentration of harmful chemicals in its body?

Peacock, Frog, Grass, Snake, Grasshopper

Ans. The organism which occurs at the highest trophic level in the food chain will have the maximum concentration o9f harmful chemical in it body. In this case grass is eaten by grasshopper, grasshopper is eaten by frog, frog is eaten by snake and snake is eaten by peacock. According to it,

Peacock occurs at the highest trophic level, therefore peacock will have the maximum concentration of harmful chemicals in its body.

(45) How Ozone gas is formed?

Ans. Ozone is formed high up in the atmosphere by the action of ultraviolet radiation on oxygen gas.

(46) Why ozone layer is very important for the existence of life on earth?

Ans. This is because it absorbs most of the harmful ultraviolet radiation coming from the sun and prevents them from reaching the earth.

(47) Define garbage. Give some example.

Ans. The household wastes is called garbage.

Ex. Waste paper, unwanted plastic objects, glass articles, metal objects etc.

(48) Write the name of some important methodes of waste disposal.

Ans. They are – Recycling, Preparation of compost, Incineration, Landfill, sewage treatment.

(49) What is Incineration?

Ans. Incineration means reducing to ashes. The burning of substance at high temperature to form ash is called incineration.

(50) Briefly describe all the method of waste disposal.

Ans. All the method of waste disposal are –

Recycling: The solid wastes like paper, plastics and metal etc are recycled.

Ex. Send of waste paper to paper mills where it is reprocessed to form new paper once again.

Preparation of compost: Biodegradable domestic wastes such as left over food, fruit and vegetables and leaves of potted plants etc can be converted into compost by burying in a pit dug into ground and used as manure.

Incineration means reducing to ashes. The burning of substance at high temperature to form ash is called incineration.

Landfill: The disposal of wastes by putting it in low lying areas of ground and covering it with earth is called land fill.

Sewage Treatment: The dirty drain water containing urine and faeces which is carried from our homes by the underground pipes is called sewage.

If untreated sewage is dumped into the river it can pollute the river water. Thus sewage is disposed of by treating it at the sewage treatment plant. The treatment of sewage produces clean water which is discharged into the river. The organic matter present in sewage is digested in the digesters of sewage treated plant to produce sewage gas and manure.

(51) Write the beneficial effect of using paper cups.

Ans. (i) Paper cup are biodegradable. So after using when it is thrown it will decompose automatically by the action of microorganism in due course of time. So no harms will effect in the soil.


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