i am posting the notes of biology for the students of std 9th.....hope it will help you all

Tissue

(By ABHISHEK SIR)

Q: Are plants and animal made of same type of tissue? Give reasons.

Ans: No, plants and animals are not made of same type of tissue because plants are stationary and cannot move. To stand in one place for long they need supportive tissues which could provide structural strength. Most of these tissues are dead. Whereas animals move around and consume more energy so the tissue is living.

Secondly, the growth of plants is limited to certain regions so the tissues divide throughout their life whereas growth in animals is more uniform and so there is no demarcation of dividing and non-dividing regions.

Q: What are meristematic tissues? What are its types? Mention their roles.

Ans: The tissue which helps in dividing and occurs only in certain regions is called meristematic tissue. These tissues are of three types:

ØApical meristem -it is present at the tips of stems and roots and    ‘                                                                                                                                                                           helps in increasing their length.

ØLateral meristem –it helps to increase the circumference of stem and roots.

ØIntercalary meristem -it is present at the base of leaves or at the internodes on twigs which helps them to grow.

Q: Explain the structure of meristematic tissues?

Ans: The meristematic tissue, in the plants cell is broadly divided in three parts:

ØThe uppermost part- Apical meristem

This is present at the tip of roots and leaves and helps in increasing their length.

ØThe middle part- intercalary meristem

This is present at the base of the leaves or internodes on twigs which help them to grow this helps to increase the thickness of leaves and roots.

Q: What is tissue?

Ans: The group of cells similar in structure and performing similar functions is called tissues.

Q: Define histology.

Ans: The branch of biology which deals with the study of tissue is histology.

Q: Are plants and animals made of tissues? Give reasons to support your answer.

Ans: Both plants and animals perform different functions based on which their tissues are developed. The structural organization of organs and organ system are far more specialized and localized in complex animals than even in very complex plants. There is fundamental difference between the modes of life persuaded both plants and animals, particularly in their different feeding methods. They are even differently adapted for carrying out their locomotion. All these differences in their characteristics demand the differences in the structures of their tissues.

Q: Differentiate between plant tissues and animals tissues.

Ans:

	Plants Tissues	Animal Tissues
1.	Ø Abundance Dead supportive tissues are more abundant as compared to living tissues.	Living tissues are more common than dead tissues.
2.	Ø Basic nature There is a differentiation between meristematic and permanent tissue.	Such a differentiation is absent.
3.	Ø Organization The organization of plant tissues is simple.	The organization is complex with the development of more specialized and localized organs and organ system
4.	Ø Purpose Tissue organization is a towards stationary habit.	Tissue organization is towards high nobility.
5.	Ø Meristematic tissue Due to its activity plants continue to grow throughout its life.	It is absent. Animals do not show growth after reaching a certain period is however present.

Q: Define meristematic tissue?

Ans: It is a plant tissue of thin compactly arranged immature cells that have the potential to divide and form new cells. Meristematic tissue is also called meristem. Its cells are called meristematic cells. The region where meristem is present can function as growth region.

Q: Mention the characteristics of meristematic cells:-

ØShape and size

   The cells are small spherical or polynomial in outline.

ØCell wall

   It is thin and elastic.

ØIntercellular space

   They are absent the cell are compactly arranged

ØCell content

●Nucleus is large

●Cytoplasm is dense

●Vacuoles are absent or very small

ØActivities

●Respiration is rapid

●Meristematic cells grow and divide rapidly

●Food supply is high but food is not stored

ØFunctions

●Meristematic tissue is the parent tissue from which other tissues       develop.

●Meristematic tissue takes part in growth by formation of new cells.

●the shoots lodged/bent by wind are made to grow upright by the activity of intercalary meristem.

Q: Explain the different types of meristematic tissue?

Ans: On the basis in the plant body, meristems or meristematic tissue are of three types:

ØApical

ØIntercalary

ØLateral

ØApical meristetem

●It occurs at the growing tips of stems and roots.

●Apical meristem produces growth in length of root and stem.

ØIntercalary meristem

●Intercalary meristem is the left out part of the apical meristem.

●It occurs in the intermediate position at the base of leaves, base of internodes (e.g. grasses) or below the nodes (e.g. mint)

●Intercalary meristem helps in growth of leaves and internodes.

ØLateral meristem

●It occurs on the sides both in stem and root.

●Lateral meristem is of two types: vascular cambium and cork cambium.

●Lateral meristem increases the girth of stem and root.

Q: Define permanent tissue.

Ans:

ØThey are plant tissues where the cells have lost the ability to divide, and have assumed a permanent shape, size and function.

ØPermanent tissues are differentiated and specialized meristematic cells.

ØTheir cells may be living or dead, thin walled or thick-walled.

Q: Mention the characteristics of permanent tissue.

ØShape and size:-The cells have attained a definite shape and size which do not alter afterwards.

ØSpecific functions:-Permanent cells come to have specific functions.

ØCell wall:-It can be thin and thick the thickening may be regular or irregular.

ØDivision:-Permanent cells normally do not divide.

ØGeneral:-They may be living or dead.

Q: What are the different types of permanent tissues?

Ans: Permanent tissues can be classified as

ØSimple

ØComplex

Q: Mention the characteristics of simple permanent tissues?

Ans: There are the permanent tissues in which the permanent cells are similar in structure, origin and function. Simple permanent tissues are of three types:-

ØParenchyma

ØCollenchyma

ØSclerenchyma

ØParenchyma (Para-beside enchyma-filling)

Structure:-

●This tissue is composed of large, thin-walled cells which are generally oval or spherical.

●The cells are not packed closely, i.e. there are intercellular spaces.

Location:-

●These living cells with a nucleus and a vacuole are found in the soft parts of the plant (stem, root, leaves, flower, fruits etc.).

Mesoplyll cells of the leaves in chloroplast contain parenchyma. The vascular tissues also contain parenchyma.

Function:-

●They store food, fill up spaces for the other tissues and provides temporary support to the plants.

●Presence of intercellular spaces between parenchyma cells allows the gases exchange.

●Certain parenchyma cells store waste products like tannins, resins, gums etc..

Chlorenchyma: Parenchyma containing chloroplasts is called chlorenchyma. Chlorenchyma is present in the leaf interior as well as outer cortex of young stems. It is a site of photosynthesis, i.e. preparation of food.

Aerenchyma: it is modified parenchyma found in hydrophytes or aquatic plants. Aerenchymas which enclose large air cavities. Air cavity stores gases and provide buoyancy to aquatic plants.

Epidermis: It is specialized Parenchyma present on the surface of plant organs.

ØCollenchyma (Kolla-glue, enchyma- tissue)

Structure:-

●It is a simple permanent tissue of living cells that provides flexibility to soft aerial parts (leaves, so that they can bent without breaking.

●The cell processes when thickenings of pecto cellulose, generally at the corners.

●Intercellular spaces are little.

●The cells are elongated but appear oval, circular or angular.

Location:-

●Collenchyma occurs below the epidemics in leaf stalks, leaf midribs.

Function;-

●Strength- it is a living mechanical tissue which provides both mechanical strength and flexibility. Because of collenchymas, plant organs can bend without breaking.

●Growth:- It allows growth and elongation of organs.

●Storage- Being living tissue, colenchyma stores food.

●Photosynthesis –Collenchyma cells may contain chloroplast and take part in photosynthesis.

ØSclerenchyma (Sclerous-hard, enchyma-tissue)

Structure:-

●It is a simple permanent tissue of highly thick- walled cell with narrow lumen.

●The thickening is generally made up of lignin which functions like a cement and hardens the cell wall.

●Sclerenchyma is of two types:

1. Fibers

2. Sclereids

Location:-

●Sclerenchyma occurs around vacular bundles, inside xylem and phloem, hard coverings of seed and nuts, hush of coconut etc.

Function:-

●Mechanical strength-It is a chief mechanical tissue of plants which provides them strength and enables them to bear various stresses.

●Protection:- it forms a protective covering of seeds and nuts.

●Commercial fibers: - sclerenchyma fibers of some plants are commercially exploited. Example-jute, flax, hemp, coconut fibers etc.

Protective Tissue

ØIt is an outer layer of cells that covers plants parts (stem, roots, leaves, fruits, flowers etc.) providing protection against adverse environmental conditions and pathogens, besides performing specialized functions like exchange of gases.

ØProtective tissues are of two types:

●Epidermis

●Cork

Q: Mention the characteristics of complex permanent tissues?

Ans: They are those permanent tissue which are made up of more than one type of cells which work together to perform a particular functions.

Common complex permanent are conducting or vascular bundles. They are:-

1.  Xylem

2.  Phloem

ØXylem (xylem-wood)

It is a complex permanent plant tissue which takes part in conduction of water and mineral salts inside the plants. In addition, it provides mechanical strength. It contains four types of cells:-

1.  Tracheids

2.  Vessels

3.  Xylem fibers

4.  Xylem parenchyma

ØPhloem (Phloeis-Inner bark)

It is complex permanent plant which takes part in conduction of organic food inside the plants. It is also called living conducting tissue as its transport channels are made up of lining cells. It is made up of four types of cells:-

1.  Sieve tubes

2.  Companion cell

3.  Phloem fibers

4.  Phloem Parenchyma

Xylem:-

1.  Tracheids-

·       Elongated cells with pointed ends

·       No nucleus and cytoplasm at maturity

·       Walls are thickening with the deposition of lignin, except certain points called “pits”.

Function

·       Conduction of water and minerals

·       Mechanical support

2.  Vessels-

·       Elongated with blunt ends.

·       No nucleus and cytoplasm at maturity

·       Walls are lignified but preforations are present at the end of their walls.

·       Each vessel is made up of a series of cells.

Function:

·       Conduction of water and menials

·       Mechanical support

3.  Xylem fibers-

·       These are sclerenchymatons fibers with pointed ends, thick walls and narrow lumen.

Function:

·       Mechanical support

4.  Xylem Parenchyma-

·       These are thin-walled living cells.

Function

·       Stores food

·       Lateral conduction of water

Phloem:

1.  Sieve tubes-

·       Like vessels, sieve tube is also made up of many cells where each cell is called sieve tube element

·       Have lining cytoplasm without nucleus at maturity

·       End wall are called “sieve plates” and these plates have perforation called “sieve pores”.

Function

·       Conduction of food

2.  Companion cell-

·       They are long narrow, thin walled. Nucleated cells associated with sieve tube elements.

Function

·       They control their own activity as well as the activity of sieve tube element

3.  Phloem fibers-

·       These are sclerenchymatous fibers with pointed ends.

·       Thick walled “fibers” with narrow lumen.

Function

·       Mechanical support

4.  Phloem parenchyma-

·       These are thin walled living cells.

Function

·       Storage of food.

Q: How animal tissues are classified?

Ans: Animal tissues are classified into four categories:

ØEpithelial

ØConnective

ØMuscular

ØNervous

Q: Mention the characteristics of epithelial tissue.

Ans:

Ø Epithelial tissue covers most organs and cavities of the body.

Ø Epithelial tissue cells are tightly packed in a single or multi-layered sheet.

Ø Epithelial tissue cells are tightly packed in a single or multi layered sheet.

ØThey have only a small amount of cementing material between them and almost no intercellular spaces.

ØAll the types of epithelial tissue rest on an extra cellular fibrous ‘basement membrane’.

ØThe epithelial cell process the power of division and regeneration.

Q: How epithelial tissues are classified?

● Squamous Epithelial tissues

ØIt is composed of thin flat cells which are arranged like the tiles of a floor.

ØThe cells have centrally placed nucleus which is round or oval.

ØAll the cells rest on delicate and non cellular ‘basement membrane’.

ØIt is present in ‘lung alveoli’, Bowman’s capsule of nephron in kidney and blood vessels.

ØHelp in the exchange of material across them by simple diffusion.

ØCuboidal epithelial tissue

Characteristics:

● It is composed of cuboidal cells

● The cells have centrally placed rounded nucleus.

● All the cells rest on delicate and non-cellular ‘basement membrane’.

● Some cells of their epithelium may become specialized or gland which may secrete substances. These epithelia are called glandular epithelia

● It is present in kidney and sweat glands.

Functions:-

● Helps in secretion, absorption and excretion.

ØColumnar Epithelial tissue

Characteristics

● It is composed of ‘elongated cells’ which are placed side-by side like columns.

● The nucleus is oval-shaped and generally placed near the base.

● All cells rest on delicate and non-cellular ‘basement membrane’.

● sometimes, hair like projections are present on the outer surface of the epithelial cells.

These types of epithelium are called ‘ciliated columnar epithelium’.

● It is present in the living cells of alimentary canal.

● Tree ends of intestinal cells have striated border which is helpful in absorption.

ØStratified epithelium

Characteristics

● It is composed of “several layers’ of cells.

● The cells of outer layer becomes flat and hard.

● The innermost layer rests on basement membrane and is called ‘germinating layer’.

●it is present in the epidermis of skin, mouth, oesophagus and cornea.

Function

● A little role in secretion and absorption but provides to the underlying tissues.

Connective Tissues

Ø This tissue serves to connect or bind the cells of other tissues in the body and gives them rigidity and support.

ØThe connective tissue is found throughout the body.

ØIt is generally made up of three basic components:

● Lining cells

● Thick, fibrous structures called fibers.

● Non-lining intercellular matrix.

Q: How Connective tissues are classified?

Ans: Connective tissues are of three types

●Connective tissue Proper

●Skeletal tissue

●Vascular tissue

Characteristics:-

ØIn this type of tissue, the matrix is relatively less rigid. It is classified into two groups:

1.  Loose connective tissue

2.  Dense connective tissue

Loose connective tissue

·       It is most common connective tissue having ground substances and most of cells and fibers.

·       It has rich blood and nerve supply.

·       It is of two types:

A. Areolar

B. Adipose

A.  Aerolar

ØIt is the most widely distributed connective tissue in the body.

ØIt consists of ground substances (matrix), white and yellow fibers and irregular cells scattered in the matrix.

ØThis tissue is found in between skin and muscle around blood vessels and nerves and in the bone narrow.

ØIt supports internal organs and helps in the repair of the tissue.

B. Adipose

Ø It is modified aerolar tissue. Cells store flat globules, hence called adipose cells or ‘adiposities’ (fat cells).

ØIt is present below the skin and between the internal organs.

ØIt is more in females as compared to males.

ØThis tissue stores fat and acts as an insulator.

●Dense connective tissue

ØThis tissue has more fibers than cells in matrix.

ØThis tissue is of two types:

A. Tendons

B.  Ligaments.

Basically the connective tissue Proper is classified into five groups.

     I.        Aerolar tissue

   II.        Adipose tissue

 III.        White fibrous tissue

IV.        Yellow elastic tissue

  V.        Reticular tissue

Q: Differentiate between tendons and ligaments.

Tendons	Ligaments
It is a dense connective tissue which joins muscle to bones	It is a dense connective tissue which joins bones to bones
They have parallel arranged collagen fibers	They have loose network of irregular by arranged yellow fibers
They are strong and inelastic	They are strong and inelastic

●Skeletal tissue

ØIt is of two types:

·       Cartilage

·       Bone

ØIn this tissue, the matrix is quite rigid.

Q: Difference between bones and cartilage

Ans:

Bone	Cartilage
It is rigid, non-flexible and strong structure. We cannot bend the bones.	It is a semi-rigid, soft and flexible structure. We can fold the cartilage of ears.
Matrix is made up of a protein called ‘Ossein’.	Matrix is made up of a protein called ‘chondrin’.
Bone cell (Osteocytes) are provided with canaliculi so that they get inter connected with each other.	Cartilage cells (chondrocytes) are not provided with canaliculi.
Matrix has the deposition of calcium and phosphate.	There is no deposition of calcium and phosphate.
Mammalian bones show haversion system.	There is no haversion system
Bone cells are arranged in concentric circles.	No arrangement of concentric circles.

●Vascular tissue

·       It is also known as blood vascular tissue.

·       It comprises of blood and lymph.

·       This tissue helps in the transport of materials from one place to another.

Q: What is blood? What are the components of blood?

Ans: Blood is a bright red colored fluid connective tissue. The liquid matrix of the blood is called ‘plasma’ which is a straw colored fluid. The plasma contains the different types of corpuscles or cells (60% plasma and 40% blood cell).

As we discussed that the blood comprises of a fluid part called plasma and the blood corpuscles or cells. The different types of blood cells are:

·       Erythrocytes or RBCs or Red Blood Cells

·       Leucocytes or WBCs or White Blood Cells

·       Blood Platelets or Thrombocytes.

Q: Mention the functions of blood.

Ans: ØRBCs helps in transport of oxygen and carbon di oxide.

ØIt helps in the transportation.

ØIt helps in the distribution of hormones.

ØBlood maintains water level of the body.

ØIt also maintains the body temperature.

ØBecause of the WBCs, it provides resistance to the body.

ØBlood platelets help in blood clotting.

Q: what is lymph? Explain.

Ans: It is the slightest, clear, straw-colored, alkaline fluid present in the lymphatic vessels. It resembles blood plasma in composition except that it does not have RBCs and proteins and contains less calcium and phosphorous than blood.

The functions of lymphs are as follows:

ØIt picks up fats from intestine for pouring into blood.

ØIt transfers newly formed ‘lymphocytes’ from lymph nodes into the blood.

ØIt provides immunity because it contains lymphocytes.

MUSCULAR TISSUE

Muscular tissues are made up of elongated cells called muscle fibers. Some of the characteristic features of muscular tissues are as follows:

ØMuscles contains special protein (myosin and actin) called contractile protein which helps in ‘movement’ and ‘locomotion’.

ØThe cytoplasm of muscle fibers are called sarcoplasm and its ER is called sarcoplasmic recticulum (SR).

ØSome muscle fibers made be bounded by a specialized membrane called sarcolemma.

ØA muscle fiber may contain many myofibrils arranged along its long axis.

Q: what are the different types of muscular tissue?

Ans: On the basis of structure, location, functions the muscular tissue are grouped in 3 categories:

ØUnstraited muscles.
ØStaited muscles

ØCardiac muscles.

Q: Differentiate between unstraited, straited and cardiac muscles.

Ans:

Unstraited	Straited	Cardiac
They are involuntary muscles.	They are voluntary muscles.	They are involuntary muscles.
Fibers are long spindle shaped.	Fibers are long and cylindrical	Fibers are short and cylindrical
Fibers are not interconnected.	Not interconnected	Interconnected
They are not show alternate light and dark bands.	They have alternate light and dark bands	They have alternate light and dark bands
They are found in the alimentary canal & blood vessels	These muscles are present in general musculature.	There fibers are found in the heart region.

NERVOUS TISSUE

Q: what is the nervous tissue made up of?

Ans: The nervous tissue is made up of specialized cells called neurons.

Q: What is neuron?

Ans: Neurons is the structural and functional unit of the nervous system. These are long and may be upto a meter long.

Q: Explain the structure and function of neuron?

Ans: A neuron consists of two distinct regions:

ØCell body (SOMA) - it contains nucleus and granular cytoplasm. The granular particles are called nissll’s granules. Our cell organelles are also present in the cytoplasm.

ØCytoplasmic processes- from the cell body two types of cytoplasmic processes come out.

·       Dendrons- they are short protoplasmic extensions which break up into 5 branches called dendrites. These processes conduct nerve impulses toward the cell body.

·       Axon- it is long, generally unbranched protoplasmic extension of the neuron. At its terminal end, it gives rise to many branches which are known as nerve ending or axon terminal or telodendrons. Axon conducts nerve impulses away from the cell body. The axon may be covered by a myelin sheath which is broken at intervals called nodes of ranvier. If these sheaths are present then the neurons are called medullated or myelinated neurons.

Functions:

Ø Neurons receive and conduct sensations in the form of electrical impulses.

Ø The impulses travels from one neuron to another through the junction point called synapse.

                        (Diagram of neuron)

IMPROVEMENT OF FOOD RESOURCES 

(BY ABHISHEK SIR)

1) How can we meet the increasing demand of production?

Ans: - Since our production is increasing rapidly, so in order to meet the increasing demand of production, we need to increase the field of agriculture and animal products and this can be done by increasing

 Or improving the production through modern scientific techniques.

2)  Why is it necessary to improve the plants and animals?

Ans: -The answer to this question can be explained in a way that the most fundamental reason for            improving the plants and animals is supplying food to the increasing population of our country. It has been estimated that more than a quarter of a billion tones will be required every year in very near future. So we can say that ‘population explosion’ for the improvement of food resources i.e. plants and animals.

3)  Is the current level of production sufficient for us?

Ans: -The current level of production which includes the input like ‘agricultural revolution’ and other conventional method might have supplemented our demand of food to some extent so far. But now, we have come to a point that on one hand the agricultural revolution have definitely increased the production to a much higher level but on the other hand it has led to overuse of natural resources. So, in this way no more increase of food produce can be carried out further. Therefore, here comes the necessary for improvement of crop yields.

4)  What are the major groups of activities for improving crop yields?

Ans: -The major group of activities for improving crop yield can be classified as:

Ø  Crop variety improvement

Ø  Crop production improvement

Ø  Crop protection management

·         Crop variety improvement-This approach depends upon finding a crop variety that can give a good yield. Varieties or strains of crops can be selected by breeding for various useful characteristics such as disease resistance, response to fertilizers, product quality and high yields. On way of incorporating desirable characters into crop varieties is by hybridization. Another way of improving the crop is by introducing a gene that would provide the desired characteristics. This results in genetically modified crops.

·         Crop production management-The different farming practices and agricultural technologies that are implemented by a farmer for raising a crop and finally selling it can be called crop production and its management is known as crop protection management. The production practices can be at different levels, i.e. from no cost production to high cost production depending on the inputs.

·         Crop protection management-After raising any crops by following proper crop production management its protection is a must. The field crops are infested by a large number of weeds, insect pests and disease. If weeds and pests are not controlled at appropriate time then they can damage the crops so much that most of the crops will be lost. The crop protection management involves application of weedicides, pesticides, proper storage of food grains and other crops.

5) Define hybridization.                                                                                                                          Ans: - Hybridization is a process of crossing between genetically dissimilar individuals. The organisms obtained as a result of crossing over is known as hybrid.

6) What are the factors for which crop variety improvement is done?

 Ans: -The factors for which crop variety improvement is done are:

Ø  Higher yield

Ø  Improved quality

Ø  Biotic and abiotic resistance

Ø  Change in maturity duration

Ø  Wider adaptability

Ø  Desirable agronomic characters

7) What is nutrient management?

Ans:-Different plants or crops require different minerals in different quantities. Most of the nutrients are obtained by the plants or crops either from air or soil. In order to increase the yield, the soil can be enriched by supplying these nutrients in the form of manures and fertilizers. This is known as nutrient management.

8) What are manures? What are its different types?

Ans: - Manures contain large quantities of organic matter and also supplies small quantities of nutrient to the soil. Manure is prepared by the decomposition of animal excreta and plant waste.                                                                          The different types of manures are:

Ø  Compost and vermin compost

Ø  Green manure

9) Compare the use of manure and fertilizers in maintaining soil fertility.

Ans: -

MANURE	FERTILIZERS
v  They are organic substance obtained by the decomposition of animal waste and plants residue by microbes.	v  They are generally inorganic compound.
v  They are bulky as well as not easy to store and transport.	v  They are compact and hence they are easy to store and transport.
v  They are not nutrient specific.	v  They are nutrient specific.
v  They provide a lot of organic matter and humus to the soil.	v  They do not provide any humus to the soil.
v  They are comparatively cheap.	v  They are expensive.

10) What is eutrofication?

Ans: - Increase in the growth of algae and decrease in the content of oxygen gas (O₂) in water is known as eutrofication. It destroys the life supporting environment in lakes and ponds.

11) What is irrigation? Mention the sources of irrigation.

Ans: - The process of providing water to the crops in field with the help of tube wells and pumps is called irrigation. Following are the sources of irrigation:

Ø  Wells

Ø  Rivers

Ø  Lakes

Ø  Lands

Ø  Reservoir etc..

12) What is mixed cropping? Mention its advantages.

Ans: - The practice of growing two or more crops at the same time in a field is called mixed cropping.

             Its advantages are:

·         Growing crops with different requirement minimizes the risk of crop failure. If the shortage of nutrients or water makes it difficult for one crop to grow, the might still yield a good harvest.

·         It is economically beneficial too.

13) What is intercropping? Mention its advantages.

Ans: -Intercropping is a modification of mixed farming. In this two or more crops are grown in a systematic                         way. Its advantages are:

·         The seeds of the two crops are planted in definite rows, it is easier to use fertilizers and pesticides required by each crop.

·         It also helps to harvest and thresh the two crops separately.

14) What is crop rotation? What are its advantages?

Ans: - Crop rotation is the practice of growing different crops in succession in the same field.

           Its advantages are:

·         It helps in regaining soil fertility.

·         This method keeps the field under continuous production.

15) How do biotic and abiotic factors affect crop rotation?

Ans: - Crop rotation can go down due to biotic and abiotic stresses under different situation. Varieties resistant of these stresses can improve crop production.

16) Define weeds. How do they cause the loss of crop production?

Ans: - Weeds are unwanted plants which grow along with the plants. Example: Amaranthus, Chenopodium (bathua), Xanthium (gokhroo), Parthenium (congress grass) etc..

They compete with the main crops for water, sunlight and space and thereby reduce the crop yield.

17) Name the methods of weeds control.

Ans: - Some of the methods of weeds control are:

·         Physical Method –Hand weeding, Ploughing, Burning etc..

·         Chemical Method – It involves the killing of weed by spraying certain chemical called weedicides.

·         Biological Method –In this method a natural enemy of weed plant is used.

18) What are weedicides?

Ans: - Chemicals used to kill the weeds are called weedicides and are also known as herbicides. Example:

·         2,4-D (2,4 – Dichlorophenoxy acetic acid)

·         2,4,5-T( 2,4,5 – Trichlorophenoxy acetic acid)

·         T C A ( Trichlorophenoxy acetic acid)

19) How do pests affect the food production?

Ans: - There are various organisms such as rats, insects, bacteria, fungi etc. which damage the crop and reduces their yield are called the pests. It is important to protect the crop from these pests.

20) What are pesticides? Give examples.

Ans: - Certain chemicals which are sprayed to destroy the pests which affect the crops are called pesticides. Example: domex, hits- sprays, rat poison etc..

21) What are the hazards of the use of pesticides?

Ans: - Almost all pesticides are toxic to man, therefore, improper or excessive use of pesticides can be harmful or hazardous for man and animal. They may also cause environmental hazards.

22) Why storage of food grains important?

Ans: - After harvesting of crops the food grains have to be made available throughout the years. This can be done by proper storage of food grains and also facilitate the distribution of food materials.

23) Mention the factors responsible for the damage of the stored food material.

Ans: - The factors responsible for the damage of food materials are:

Ø  Biotic – These are the factors which are living organisms such as insects, microbes and rats.

Ø  Abiotic – The various abiotic factors are :

·         Temperature

·         Moisture content in food grains

·         Moisture content in air

·         Material of the container used for storage

24) Mention the preventive and control measures which are used for grain storage.

Ans: - The preventive and control measures used for grain storage are:

·         Strict cleaning of the produce before storage.

·         Proper drying of the produce so that there is no moisture.

·         Fumigation, using chemicals that can kill pests.

·         Improvement in storage structure.

25) Define:

a)      Animal husbandry – It is the scientific management of animal livestock. It can also be defined as the science of feeding, rearing, breeding and caring of farm animals.

b)     Livestock –Those animals which are reared or used commercially for obtaining their products are known as livestock.

26) Why improvement of animals is necessary?

Ans: - The main reason for the improvement of animals is to meet the increasing demand for animal products like milk, eggs and meet due to the increase in the population.

27) Mention two reasons for why a cattle farming is done?
Ans: - The two major reasons for cattle farming are:

Ø  Milk production

Ø  As draught animal for agricultural work such as ploughing.

28) Mention the names of two exotic and two indigenous varieties of cattle.

Ans: - The two varieties of cattle are:

Ø  Indigenous (Red Sindhi, Sahiwal)

Ø  Exotic ( Jersey, Brown Swiss)

29) Mention the two varieties of Indian cattle.

Ans: - The two varieties are:

Ø  Bos indicus (cow)

Ø  Bos Bubalis (buffalo)

30) How milk production can be increased?

Ans: - Milk production can be increased by:

·         Increasing the lactation period.

·         Carrying out hybridization or crossing over of higher breed.

31) What is breed?

Ans: - A breed is a group of common origin within a species with certain special identifiable characteristics.

32) Define hybrid.

Ans:- The organisms having desired characters and is a product of crossing over between superior variety is known as hybrid.

33) What are the measures that must be taken to keep the cattle healthy?

Ans: - The measures that can be taken are:

·         The animal should be kept in properly, well-ventilated shelter to protect them from heat, rain and cold.

·         Cattle sheds must be cleaned regularly.

·         The animal must be given good, nutritive field and clean water.

·         The animals be vaccinated to immunize them against common diseases or infections.

34) Give some idea about the animal feeds.

Ans: - Animal feed generally contains:

Ø  Roughage-It includes low nutrient bulky food containing relatively large amount of fiber.

Ø  Concentrates- These are the feeds which are rich in one or more materials.

35) Mention some diseases related to cattle.

Ans: - Some diseases are:

Ø  Foot and mouth diseases

Ø  Anthrax

Ø  Cowpox

Ø  Rinder paste or cattle plague

36) What are the categories in which fowl can be divided?

Ans: - Fowls can be divided into two groups:

Ø  Broilers- they are used for their meat.

Ø  Layers- they are used for laying eggs.

37) What are the steps that must be practiced to keep the poultry birds healthy?

Ans: - The steps are:

·         Maintenance of normal temperature in their place of living is required.

·         Prevention and control of diseases and pests.

·         Maintenance of hygienic condition.

·         Appropriate vaccination from time- to -time.

·         Properly balanced poultry feed should be provided to avoid any nutritional deficiency.

38) Name two breeds each of indigenous and exotic breeds.

Ans: - The two breeds are:

Ø  Indigenous-aseel, kajal etc...

Ø  Exotic-white leg horn, Rhode Island red etc...

39) Mention some diseases which poultry birds suffer.

Ans: - Some diseases are:

Ø  Fowl pox

Ø  Ranikhet

Ø  Bird flu

Ø  Fowl cholera

40) Define pisciculture.

Ans: - The rearing and management of fishes is called pisciculture.

41) What are the two categories of obtaining fishes?

Ans: - The different ways are:

Ø  Capture fishing- when the fishes are obtained from the natural resources, the method is called capture fishing.

Ø  Culture fishing-when the fishes are obtained by fish farming, it is called culture fishing.

42) Name some popular marine fishes of high economy.

Ans: - The high economic value fishes are:

           Mullets, bhetki, prawns, mussels, pearlspot

43) Name some general marine fishes.

Ans: - Some general marine fishes are:

            Pomphret, mackerel, tuna, saraines and Bombay duck.

44) What are the different ways in which inland fisheries is carried out?

Ans: - Inland fisheries can be carried out by various modes:

Ø  Fresh water resources- include canals, ponds, reservoirs and rivers.

Ø  Brackish water resources- it includes estuaries and lagoons where sea water fresh water is mixed together.

Ø  In rice field- fish culture is done in combination with paddy crops.

Ø  Composite fish culture-it is an extensive fish farming system where fishes of different species differing in feeding habit and habitat are cultured together.

45) Name some fresh water fishes.

Ans: - Some fresh water fishes are:

            Catla, rohu, grass carp, common carp, silver carp.

46) What is composite fish culture? Explain.

Ans: - This is a very intensive fish farming system. In this system, a combination of five or six fish species is a used in a single fish pond. The species in pond are selected in such a way that they should not compete for food i.e. they should have different food habitsso that they can take food in different parts of ponds.

47) What is apiculture?

Ans: - The practice of bee keeping is called apiculture. It is carried out for commercial honey production.

48) Mention the uses of honey.

Ans: - The uses are:

Ø  It is used in the treatment of digestive disorder and liver ailments.

Ø  It is a blood purifier.

Ø  It is used of treatment of cough, cold, sore throat and ulcer of tongue and stomach.

Ø  It is one of the ingredients of pastries and cakes.

49) What are some of the local and foreign varieties of bee?

Ans: - The local and foreign varieties of bees are:

LOCAL VARIETIES	FOREIGN VARIETIES
v  Apis cerena indica (Indian bee)	v  Apis mellifera (Italian bee)
v  Apis dorsata (rock bee)	v  Apis adamsoni ( African bee)
v  Apis florae (little bee)

               

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