Std.8 Ch.1 Living world and Microbes

Question 1:

Use Whittakar method to classify bacteria, protozoa, fungi, algae, prokaryotic and eukaryaotic microbes.
 

ANSWER:

The characteristic features of each of the five kingdoms classified by Whittaker are:

Kingdom Monera

• Absence of a well-defined nucleus or membrane-bound organelles

• Absence of multicellular body designs; all are unicellular

• Presence or absence of a cell wall

• Autotrophic or heterotrophic mode of nutrition

Kingdom Protista

• They are unicellular, eukaryotic organisms.

• They can be autotrophic or heterotrophic.

• Some members have cilia or flagella, which helps in locomotion.

Kingdom Fungi

• They may be unicellular or multicellular, eukaryotic organisms.

• Their body consists of mycelium, which is made up of multicellular filamentous hyphae.

• Their cell walls are made up of tough, complex sugar called chitin.

• They are saprophytes, which feed on dead organic material.

Kingdom Plantae

• They are multicellular, eukaryotic organisms.

• Cell wall is made up of cellulose and not chitin unlike that of fungi.

• Most plant cells contain chlorophyll pigments. Hence, they are autotrophic.

• They are non-motile.

Kingdom Animalia

• They are multicellular eukaryotes.

• Cell wall is absent in them.

• Chloroplast is absent in animal cells. Hence, they have a heterotrophic mode of nutrition.

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Question 2:

Complete the five kingdom method of classification using living organism prokaryotes, eukaryotes, multicellular,  unicellular, protista, animals, plants, fungi. 

ANSWER:

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Question 3:

Find out my partner 

A	B
Fungi	Chlorella
Protozoa	Bacteriophage
Virus	Candida
Algae	Amoeba
Bacteria	Prokaryotic

ANSWER:

 

A	B
Fungi	Candida
Protozoa	Amoeba
Virus	Bacteriophage
Algae	Chlorella
Bacteria	Prokaryotic

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Question 4:

State whether the following statements are true or false. Explain your statement.
A. Lactobacilli are harmful bacteria.
B. Cell wall of fungi is made up of chitin.
C. Organ of locomotion in amoeba is pseudopodia.
E. Tomato wilt is viral disease.

ANSWER:

A. Lactobacilli are harmful bacteria.- False
Lactobacilli are not harmful bacteria, infact they are found in gastrointestinal tracts of animals and humans. They are also an important part of dairy products such as milk, yogurt etc.

B. Cell wall of fungi is made up of chitin.- True
C. Organ of locomotion in amoeba is pseudopodia.- True
E. Tomato wilt is viral disease.- True

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Question 5:

Give answers.
A. State the merits of whitetaker's method of classification. 
B. Write the characteristics of viruses.
C. Explain the nutrition in fungi.
D. Which living organisms are included in the kingdom monera ?
 

ANSWER:

 a. The merits of Whitakker's method of classification are:

• Unicellular and multicellular organisms are kept under separate categories.
• Autotrophs and heterotrophs are placed in separate groups.
• A separate kingdom was assigned to fungi because of its mode of nutrition.
• It is more natural than two kingdom classification.
• Prokaryotes are placed under a separate category of monera.
   

b. The various characteristics of viruses are:

• They are smaller and simpler than bacteria.
• They are ultra microscopic and visible only under electron microscope.
• They are considered to be on the boundary line of living and non-living things. 
• They are obligate parasites and cannot live on their own.
• They cannot multiply on their own. They require living machinery to multiply.
• Viruses consist of genetic materials (DNA or RNA) surrounded by a protective coat of protein (capsid). 
• Viruses are responsible for causing many dreadful diseases in plants, animals, and humans.​

c. The mode of nutrition in fungi is saprotropic and they are called saprophytes. It is a mode of nutrition in which an organism obtains its nutrients from the decaying organic matter.

d. Organisms with following characteristics are inlcuded under the kingdom monera:

• Absence of nucleus and membrane-bound organelles
• Presence or absence of cell wall
• Can be either autotrophic or heterotrophic
• Are all unicellular and include mainly bacteria and blue green algae

Examples include bacteria and blue green algae.

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Question 6:

Who am I ?
A. I don't have true nucleus, cell organelles or plasma membrance.
B. I have nucleus and membrane bound cell orgenelles.
C. I live on decaying organic matter.
D. I reproduce mainly by cell division.
E. I Can produce my replica.
F. I am green, but don't have organs.
 

ANSWER:

A. I don't have true nucleus, cell organelles or plasma membrance. - Monera
B. I have nucleus and membrane bound cell orgenelles. - Protozoa
C. I live on decaying organic matter. - Fungi
D. I reproduce mainly by cell division.- Bacteria
E. I Can produce my replica. - Viruses
F. I am green, but don't have organs. - Algae

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Question 7:

Draw neat and labelled diagrams.
A. Different types of bacteria.
B. Paramoecium
C. Bacteriophage.

ANSWER:

a.  Structure of bacteria







b. Structure of Paramoecium






c. Structure of bacteriophage



 

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Question 8:

Arrange the follwing in ascending order of size Bacteria, Fungi, Viruses, Algade.

ANSWER:

Viruses →Bacteria →Fungi→Algae

First Unit Test Portion 2022_2023

Ch.1. The living world: Adaptations and Classification

Question 1:

Find my match!
 

'A' Group		'B' Group
(1)	Lotus	(a)	Flower and leaves attract insects
(2)	Aloe	(b)	Haustorial roots for absorption of food
(3)	Cuscuta	(c)	Adapted to live in deserts
(4)	Venus flytrap	(d)	Adapted to live in water

ANSWER:

'A' Group		'B' Group
(1)	Lotus	(d)	Adapted to live in water
(2)	Aloe	(c)	Adapted to live in deserts
(3)	Cuscuta	(b)	Haustorial roots for absorption of food
(4)	Venus flytrap	(a)	Flower and leaves attract insects

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Question 2:

Read the paragraph and answer the following questions.
I am a penguin. I live in polar region covered by snow. My abdomen is white. My skin is thick with a layer of fat underneath. My body is spindle-shaped. My wings are small. My toes are webbed. We live in flocks.
(a) Why is my skin white and thick and why is there a thick layer of fat underneath?
(b) Why do we live in flocks sticking close to each other?
(c) Which geographical region do I inhabit? Why?
(d) Which adaptations should you have to enable you to live permanently in the polar region? Why?

ANSWER:

a. Having black and white skin is a type of adaptation known as camouflaging. It is called counter-shading and makes it harder for both the predators and the prey to see penguins from all sorts of angles. The white chest of penguin protects them in the water by camouflaging them from being seen from below against the lighter sky coming through the waters surface. Their black backs help them blend in with the darker, deeper ocean waters below them, thus protecting them from their predators. They have thick layer of fat because it keeps them warm under such extreme cold conditions.

b. We know that penguins live in the coldest regions of earth and in order to find warmth and solace they remain in flocks with each other. In order to escape the extreme cold conditions, they nestle together to keep each other warm. 

c. Penguins are found in regions of Antarctica, South America, Africa and Australia. Many species can also be found in New Zealand and the sub-Antarctic islands. 

d. The following adaptations are required to survive in polar regions:

• black and white skin with a thick layer of fat beneath it
• skin should be covered with feathers
• small body with small wings
• presence of strong muscles in chest and wings

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Question 3:

Who is lying?
(a) Cockroach – I have five legs.
(b) Hen – My toes are webbed.
(c) Cactus – My fleshy, green part is a leaf.

ANSWER:

The cockroach is lying beacuse it has six legs and not five.
The cactus is also lying because its fleshy, green part is a stem and not a leaf.

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Question 4:

Read each of the following statements. Write a paragraph about adaptation with reference to each statement.
(a) There is extreme heat in deserts.
(b) Grasslands are lush green.
(c) Insects are found in large numbers.
(d) We hide.
(e) We have long ears.

ANSWER:

a. There is extreme heat in deserts and dry conditions prevail in this region. The animals and plants which are found in this region have special modifications which help them to survive in such environment. For example, cactus and acacia plants withstand hot and dry environment of the desert with the help of various modifications. They have thick cuticle on their leaf surface and their stomata are arranged in deep pits to minimise water loss by transpiration. They have special photosynthetic pathway, CAM in which stomata remains closed during day time. Their leaves are reduced to spines to minimise water loss, and photosynthetic functions are performed by flattened stems.
Similarly desert animals have adaptive features like- thick skin to prevent the loss of water, long legs with flat and cushioned soles, long and thick eyelashes and nostrils which are protected by folds of skin.

b. Grasslands are lush green due to the presence of diverse types of bushes and grasses. Grasses are tall so that animals like tiger, lion, elephant can remain hidden in them. Animals which are found in grasslands have adaptations like strong legs to run fast and capture their prey, claws, sharp and pointed canine. The herbivores which are found in this region have eyes below the forehead which gives them wide angle vision which protects them from predators.

c. Insects are found in large numbers because they have developed mechanisms which help them to survive even in harshest of environment. They are found in extreme conditions of deserts and Antartic region due to these modifications. For example grasshopper have long, strong hind legs that help them jump, house flies have sponging mouthparts to slurp up food, stinky bugs and walking sticks have the ability to camouflage.

​d. There are certain species which are able to hide themselves by blending their colour with that of the surrounding. This adaptive mechanism is termed as camouflage and is a method to protect oneself from the predators and prey. For example, grasshopper, lizards, butterflies, chameleon, frogs etc.

e. Animals with long ears are found in grasslands. It is an adaptive mechanism which enables them to receive sounds from long distances and from different directions. Another important function of long ears is that they act as a cooling system. 

The large ears have thin skin and contain an extensive network of blood vessels that provide a large surface area for heat exchange. These vessels swell when the animal is hot to allow the blood to cool and contract when temperatures drop to conserve heat.

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Question 5:

Answer the following.
(a) Why is the camel called the 'Ship of the desert'?
(b) How can the plants like cactus and acacia live in deserts with scarce water?
(c) What is the inter-relationship between adaptations of organisms and their surroundings?
(d) How are organisms classified?

ANSWER:

a. Camel is called the "Ship of Desert" because it is the only means of transport found in deserts. The body of a camel has undergone various modifications that help it to survive in the hot and dry conditions of the deserts.

• Camels have very long legs that help them to walk in the sand and prevent the heat of the sand from reaching their bodies. 
• They have a prominent back or hump. It stores food which helps it to survive without food in the deserts for several days.
• Another important adaptation that helps the camel to survive in the desert is its ability to conserve water. They do not sweat and excrete only small amounts of water through urine. The camel dung is dry and devoid of water.
• All this helps the camel to conserve water and enables them to live without water for several days.

b. Cactus and acacia plants withstand hot and dry environment of the desert with the help of various modifications. They have thick cuticle on their leaf surface and their stomata are arranged in deep pits to minimise water loss by transpiration. They have special photosynthetic pathway, CAM in which stomata remains closed during day time. Their leaves are reduced to spines to minimise water loss and photosynthetic functions are performed by flattened stems.

c. Adaptation is defined as the modification or change in the organism's body or behaviour that helps it to survive in a particular environment. The environment in which an animal survives consists of many different things and it must learn to adapt to each of these factors in order to survive. These factors can be in the form of climate, the kinds of food plants that grow in it, other animals that may be predators or competitors etc. This fact is evident from the following examples:

• Cactus has thick cuticle on their leaf surface and their stomata are arranged in deep pits to minimise water loss by transpiration. They have special photosynthetic pathway, CAM in which stomata remains closed during day time. Their leaves are reduced to spines to minimise water loss, and photosynthetic functions are performed by flattened stems.
• Camels have very long legs that help it to walk in the sand and prevent the heat of the sand from reaching their bodies. The camel has a prominent back or hump. It stores food which helps it to survive without food in the deserts for several days.

d. The hierarchy of classification was developed by Carolus Linnaeus. It refers to the organisation or classification of organisms in the order of rank or importance. According to this system, kingdom is the highest rank. It is divided into phyla or divisions, which are further subdivided into classes. Further divisions include order, family, genus and species, in that order. Thus, species is the basic unit of classification.

Std.VI Ch.1.Natural Resources

Question 1:

Fill in the blanks.
(a) The layer of ozone gas absorbs ………… rays that come from the sun to the earth.
(b) Of the total water available on the earth, fresh water forms ...... percent.
(c) Both ...…. and ……... constituents are present in the soil.

ANSWER:

(a) The layer of ozone gas absorbs UV rays that come from the sun to the earth.
(b) Of the total water available on the earth, fresh water forms 0.3 percent.
(c) Both biotic and abiotic constituents are present in the soil.

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Question 2:

Why is it said that – ?
(a) The ozone layer is a protective shell of the earth.
(b) Water is life.
(c) Seawater is useful even though it is not potable.

ANSWER:

a. The ozone layer acts as a protective layer for life on the earth because it absorbs harmful ultraviolet radiations of the sun. These radiations, if reach the Earth’s surface, can cause skin cancer.

b. Water is one of the most precious resource which we have on earth. All the biochemical processes which occur in plants and animals, our surroundings etc. require water to function. It is required for the existence of life on earth as it is an essential component of all the biological processes. We cannot imagine our lives without the presence of water. 

c. Although sea water is not potable, it has various other kinds of uses which prove its importance:

• Water from oceans can be used for making hydroelectricity, a form of renewable source of energy.
• It can be used as a cheap transport method.
• They can be used for the activities like scuba diving, water sports etc. which is a means of boosting the tourism and economic growth of a country.
• Nuclear power plants require coolants like water to bring down the temperature of the reactors. For this purpose several gallons of water is required and this demand is fulfilled by the water from oceans.
• They support a variety of flora and fauna which have both ecological and economical value.

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Question 3:

What will happen if –
(a) Microbes in the soil get destroyed.
(b) The number of vehicles and factories in your surroundings increases.
(c) The total supply of potable water is finished.

ANSWER:

a. Soil contains various kinds of microbes like bacteria, fungi, algae, protozoa etc. All of these microorganisms play an important roles like:

• Certain bacteria and blue-green algae have the ability to fix atmospheric nitrogen. This, in turn, enriches the fertility of soil. Such microorganisms are known as biological nitrogen-fixers. Example − Rhizobium is a symbiotic bacterium which lives in the root nodules of leguminous plants. Rhizobium fixes atmospheric nitrogen into nitrogenous compounds.
• The bacteria and fungi present in soil decompose dead organic wastes of plants and animals, and convert them into manure. The manure contributes to the humus content of the soil, thereby helping in increasing its fertility.
• Not only these, microorganisms which are found in soil are also a part of many biogeochemical cycles which would not take place in their absence.

The above points explain the fact that how important microbes are and if they are destroyed its effect can be irreversible.

b. Vehicles and factories are the major sources of air pollution. If the number of vehicles and factories increase in our surroundings, it is obvious that it would result in increased levels of air pollution. Not only air pollution but they also result in noise pollution. In case, the no. of industries increase in our surrounding it means, more trees would have to be cut down to make way for them and thus resulting in damage to the environment.

c. If the total supply of potable water is finished then the life on earth will end. Water is required for the existence of living beings and in its absence, it owuld hamper their developemnt process and their survival.

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Question 4:

Match the following.
 

Group ‘A’		Group ‘B’
(1)	Carbon dioxide	(a)	Generation of soil
(2)	Oxygen	(b)	Rain
(3)	Water vapour	(c)	Plants and food production
(4)	Microbes	(d)	Combustion

ANSWER:

Group ‘A’		Group ‘B’
(1)	Carbon dioxide	(c)	Plants and food production
(2)	Oxygen	(d)	Combustion
(3)	Water vapour	(b)	Rain
(4)	Microbes	(a)	Generation of soil

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Question 5:

Name the following.
(a) Constituents of the biosphere
(b) Biotic constituents of soil
(c) Fossil fuel
(d) Inert gases in air
(e) Gases that are harmful to the ozone layer

ANSWER:

(a) Constituents of the biosphere- hydrosphere and atmosphere
(b) Biotic constituents of soil- microorganisms and insects
(c) Fossil fuel- coal and petroleum
(d) Inert gases in air- oxygen and nitrogen
(e) Gases that are harmful to the ozone layer- carbon tetrachloride

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Question 6:

True or false?
(a) Land and soil are the same thing.
(b) The water in a lake is called ground water.
(c) It takes about 1000 years to form a 25 cm thick layer of soil.
(d) Radon is used in decorative lights.

ANSWER:

(a) Land and soil are the same thing.- False
(b) The water in a lake is called ground water.- Flase
(c) It takes about 1000 years to form a 25 cm thick layer of soil.-False
(d) Radon is used in decorative lights.- False

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Question 7:

Answer in your own words.
(a) Explain with the help of a diagram how soil is formed.
(b) Why is there a shortage of water even though it occupies about 71% of the earth’s surface?
(c) What are the various constituents of air? Write their uses.
(d) Why are air, water and land considered to be valuable natural resources?

ANSWER:

a. Soil is formed by the process of weathering during which rocks break down to form soil particles. This breaking down of rock occurs over a period of millions of years. Weathering can be physical, chemical, and biological. The bedrock breaks down into pieces due to the effects of heat, cold, water, wind and rain. Microbes, insects and rodents also help iin this process. The roots of trees also help in the process of weathering.




b. Although water occupies about 71% of the earth's surface, all of it is not potable water. Most of the water is available in the form of seas and oceans which is salty in nature. This saline water has its limitations and cannot be used for many purposes. Around 2.7% of water exists in frozen state or as groundwater which is unaccessible. Only 0.3% of water is available as potable water which is fit for human consumption.

c.

Constituents of air	Uses
1. Nitrogen	Required in building proteins. Useful in production of ammonia. Used in airtight packaging of food products.
2. Oxygen	Necessary for respiration and combustion.
3. Carbon dioxide	Used by plants to make their foods. Used in fire extinguishers.
4. Argon	Used in electric bulbs.
5. Heluim	Used for obtaining low temperatures. Used for generating lifts in airships.
6. Neon	Used in decorative lights and street lighting.
7. Krypton	Used in fluorescent tubes.
8. Xenon	Used in flash photography.

d. The following points elucidate the fact that air, land and water are valuable natural resources:


Importance of air:

• The importance of air can be understood by the fact that earth supports life becuase of the present of this air in our surrounding.
• It is required for various biological functions and biogeochemical cycles.

Importance of land:

• All terrestrial organisms live on land.
• We use it for the purpose of land farming, building houses, roads etc.
• The plants and animals which we use also grow on the land.
• The minerals which we obtain from deep inside the earth are also important resources. For example, petrol, coal etc.

Importance of water:

• Water plays an important role in various vital processes that are carried out by our body. All cellular processes take place in water medium.
• The availability of water plays an important role in deciding the number of individuals of each species that will be able to survive in a particular area, and also the sustainability of life in the region. 
• Fresh water is utilized by humans for consumption. 
• Water is central to the lives of aquatic animals which live in water.

EVS I: Chapter 01- Our Earth and Our Solar System

Std.V Roman Numerals

Thank You

UNIVERSE

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