International Tiger day is celebrated on July 29 to raise awareness about the conservation of wild cat.However with several countries taking measures to curb poaching,illegal wildlife trade,and habitat loss,etc.The tiger is the largest of the world’s big cats and this magnificent creature, with its distinctive orange and black stripes and beautifully marked face, has a day that is dedicated to it.

We cannot deny the fact that tigers are the largest species of the cat family and also one of the most iconic animals on the planet.There is a very famous quote,”Where Tigers thrive,it is a sign that the ecosystem is healthy”.

Why Tigers are so important?

As top predators,Tigers help to keep their environment healthy.Generally the predators prey on other animals.In this case, herbivores such as deer.But without enough Tiger to eat them, herbivores can overgraze and damage the land, disrupting the balance of the local environment.By keeping the prey species under their control,they protect the vegetation which inturn maintains the integrity of streams,forests and crop plants that provide people around the world with clean air,fresh water,food and financial benefits.

And also Tiger is the symbol of wilderness and well being if the Eco system.By conserving and saving tigers the entire ecosystem is conserved.

Reasons for the declining population of Tigers

⭐ Tigers were poached for their furs.Tigers may prey upon agricultural animals and have been illegally shot at or poisoned by consuming baited carcasses.

⭐ From elephant ivory to orchids,the illegal wildlife trade touches tens of thousands of species around the world.Its become increasingly with organized networks obtaining, transporting, selling and bribing their ways to big profit.

⭐ Nowadays with the increasing population,forest are becoming less by clearing of forests for several reasons like agriculture, industries,etc.made a loss of around 93% of the natural habitats of Tigers.

⭐The combined effect of climate change and sea level rise leads to the wiping out of Sundarbans, one of the habitat of Bengal Tigers.

⭐ Several animals die due to certain diseases like Feline Panleucopania, tuberculosis,etc.,

Tigers are of various colours like White Tigers,Brown Tiger with black stripes,White Tiger with black stripes,and golden Tigers.Watching them walking is a lovely sight.So far the four species of Tigers including Bali Tiger,Caspian Tiger,Javan Tiger and Tiger hybrids are extinct.

According to the WWF,the current population of the wild cat is 3,900.By next year,WWF aims to double their population to 6000.International Tiger Day play a important role in it by spreading awareness and by working towards conservation of tigers.

“So protect and conserve Tigers”

Some Insects are injurious to man as vectors of human diseases.Through the ages millions of people have died of diseases transmitted by insects.There are a number of insect borne diseases,and they may be transmitted in different ways.

⭐Housefly

House flies are cosmopolitan in distribution.They are closely associated with humans and thrive best where people are careless in the disposal of wastes.Adult flies are non parasitic.They feed on all kinds of decaying and decomposing matter.It is an important mechanical vector in the transmission of diseases like typhoid, dysentery and cholera.The housefly cause diseases through food contaminations.

House fly control is normally done in three different ways, namely sanitary, mechanical and chemical methods.Populations of house flies can be controlled by proper disposal of manure, garbage,sewage,food waste,human excreta and other organic materials.Mechanical practices such as screening, using of traps or sticky paper or baits can be valuable in excluding houseflies.Insecticides may be used against larvae.Spraying with 2% malathion,1% chlordane or lindane,0.5% tremephos are effective.

⭐Sand flies

These flies are 4 mm long.Only the female possess piercing sucking mouth parts and are haematophagous.The males are non parasitic, feeding on moisture.They are small slender insects with hairy bodies.Through biting this fly transmits the disease called kala-azar.During the day time the flies remain hiding.At night they come out to feed.The sand fly attacks during night times.The insect sucks the parasite from an infected person,along with blood.Inside the body of the fly,the parasite undergoes changes.When an affected fly bites man,the parasites pass into the blood and fresh infection is effected.The parasites mostly concentrate in the capillaries of spleen,liver and bone marrow.The disease is characterized by the symptoms like anaemia and emaciation.

Spraying of 5% DDT/BHC easily kills the flies.The pyrethrum ointment used on exposed part of the body works as a repellent.

⭐Rat fleas

Both male and female fleas take in the bacillus pasteurella pestis from infected rats during feeding.This rat flea is responsible for the transmission of plague from man to man,or from rat to man.When this bacterium is introduced into the skin,the lymph glands become inflamed.This is known as bubonic plague.When the rat flea sucks the blood of man or a rat infected with plague,the bacilli enter into its stomach and grow there into larger numbers.The flea thus heavily laden with the bacilli,may bite a healthy man and introduce the bacilli into the wound and cause infection.The bacilli are deposited by the flea on the skin along with the faeces.The bite of the flea causes scratchings and the bacilli are introduced into the blood when the skin is scratched.

Destruction of rats and other rodents is an effective method.Dusting of 1 to 2% chlordane,or 2% Y-BHC is very much effective in the elimination of fleas on the body of pet animals.Application of 5% DDT is recommended for spraying at the time of the spread of plague in all areas.

⭐The human louse

Louse is a blood sucking ectoparasite of man.It is cosmopolitan in distribution.The human louse is a major vector for three important human diseases,relapsing fever,typhus and trench fever.Wearing clean clothes,and having regular bath avoids infestation.

⭐ Mosquitoes

Mosquitoes are cosmopolitan in distribution.They are nocturnal in habit and are found in abundance in damp,marshy lands near stagnant water.Only female mosquitoes are adapted to suck the blood of human beings and function as carrier of viral,protozoan and nematode diseases.

When the infected mosquito bites another person,the larvae penetrate the superficial skin to find their way into the lymphatic vessels,and attain sexual maturity.In severe infection the adults cause blocking of lymphatic system which results in the enlargement of legs,arms,scrotum,and mammary glands.Another type of mosquito transmits yellow fever through a virus.

Memory refers to the processes that are used to acquire, store, retain, and later retrieve information. There are three major processes involved in memory: encoding, storage, and retrieval. Human memory involves the ability to both preserve and recover information we have learned or experienced.

The term memory denotes a specific brain function of storing and retrieving of informations related to experiences.Tge duration of memory varies from few seconds or hours,to several years.

Types of memory

⭐Sensory memory:It means the ability to retain sensory signals in the sensory areas of the brain for a short interval of time following the actual sensory experience.This is the initial stage of memory process.

⭐ Primary memory:It is the memory of facts,words, numbers,letters,or other information.The information in this memory is instantaneously made available so that a person need not search through his or her mind for it.

⭐ Secondary memory:It is the storage in the brain of information that can be recalled at some later time(hours,days,months or years later).This is also called long term memory,fixed memory or permanent memory.

Physiology of memory: Certain anatomical, physical or chemical changes occur in the pre synaptic terminals or perhaps in whole neurons that permanently facilitated the transmission of impulses at the synapses.

All the synapses are thus facilitated in a thought circuit.This circuit can be re excited by any one of many diverse signals at later dates thereby causing memory.The overall facilitated circuit is called a memory engram or a memory trace.

Amnesia: Amnesia means memory loss.It is the inability to recall memories from the past.

An aquarium is a container made of glass,or with glass walls.It permits watching the fishes swimming easily and for prolonged periods of time.It is a hobby which appeals to young and old and has opened up a flourishing business in all big cities.

And also,next to birds,fishes are perhaps the most colourful of animals.They are graceful in their shape,body form and movement.

Setting up an aquarium tank

Tank selection: The choice of an aquarium tank,depends largely on where it is to be housed,the extent of one’s enthusiasm and the money one wants to spend.While selecting a tank it is very important to note that it is of good construction.Shallow and wide tanks are preferable as they have more surface area to facilitate oxygenation through atmospheric contact.Further such tanks can accommodate more number of fishes.

Before setting up the tank,a suitable place has to be selected.In order to get a good view of both fishes and plants in an aquarium tank,the light should come obliquely.Hence, instead of the window sill,a place nearer to its side may be selected.To avail maximum sunlight an eastern exposure is preferable.The support or table for positioning the tank must be strong and in level.It is also essential to have a cover with a provision for installing lights and feeding.

If the tanks are purchased they should be checked for leakage.Their sides should be cleaned with 1% potassium permanganate solution, besides repeated washing with tap water.The next step in the setting up of an aquarium is the collection of sand that is necessary to make the bed at the bottom of the tank.The sand for the tank bottom can be collected from the sea shore or a river.This sand has to be washed to remove the dirt.It is advisable to put the sand in a shallow pan or aluminium vessel and heating it.The cleaned sand may be exposed in the bright sun.These processes ensure the killing of all bacteria or germs.The cleaned sand should be spread evenly in the tank bottom.Over the top layer of sand a thin layer of stone chips or very small pebbles may be placed.

Quality of water for Aquarium tank

Rain water free from contaminants or tap water is ideal for aquarium tanks.A tap water of domestic supply is likely to have chlorine which is harmful to fish.This water may be stagnated for about one or two days before use.If the water is hard it must be properly treated.The tank should be filled with the desired water without disturbing the bottom sand.

Planting:The aquarium tank after being filled with water can be planned with selected varieties of aquatic plants.The plants provide shade, shelter and sanctuary for fish.Besides decorating the aquarium tank,they also help in spawning and as food for certain fishes.The plants provide oxygen through photosynthesis.Over crowding of plants has to be avoided to ensure an adequate supply of oxygen to fishes.

Lighting:Light besides beautifying the aquarium helps in the photosynthesis of aquarium plants.Fishes also require light to trace their food.Further the light is known to influence the growth of fish.Strong sunlight destroys bacteria and keeps the tank healthy.For a moderate tank bulbs of 60 watts each may be lit for eight hours a day.It is better to use fluorescent lighting for promotion of plant growth and for even distribution of light.

Introduction of fish in an aquarium tank

The number of fishes suitable for stocking in an aquarium tank depends mainly on the surface area of the tank,it’s dissolved oxygen content and size of the fish.It is reported that 1 cm long fish may lead about 75 cm^2 of the surface area.The fishes are generally introduced two or three days after planting when the water would be clear and well oxygenated by plants.Before introduction into the Aquarium tank,the fish may be treated with 2 percent potassium permanganate solution to avoid parasitic attack.

Feeding: Fishes may be fed once or twice a day according to their preference and satiation.Excess food and detritus may be removed 30 minutes after feeding,by siphoning out using rubber tubing.If the level of the water gets reduced in course of time it should be restored by the addition of some rain water or chlorine free tap water.

A large number of fishes are cultured in aquaria for their beauty and graceful movements.The movement of colour fishes in an aquarium would certainly please the ailing and convalescing people.The aquarium may gladden one’s heart.

A person who migrates or who has migrated from one country to another with a view to being employed other than on his own account.India is a vast country with high percentage of uneducated, unemployed and unskilled labour suffering from acute poverty.Regional imbalances add to their problem.Many of them are unable to find means of livelihood within their habitat.

Frequent droughts,famines and other calamities force these poorest sections to migrate.These sections of people are constantly on the move seeking avenues of manual work.Such migrants are mostly employed by contractors in road works,quarry and brick works,mining works, clearing forests and in many hazardous works.A few of them become domestic help,and some become menials in hotels and other establishments.As migrant Labour,there is no protection to their person,no guarantee of a fair wage.They are forced to live in unhygienic transit slums without clean water and nutritious food.There is no guarantee for health care and no provision for care and education of their children.

Migrant labour,means,the labour who goes on moving from place to place seeking manual employment on temporary basis.They are constantly exploited by contractors.As they work in regions of different languages it becomes very difficult to become organised and to articulate on their needs and to demand and secure necessary remedies.In fact,most of the migrant labour are treated almost like bonded labour.

Wider highways,huge buildings for industries, business and institutions are coming up fast, however the conditions of the human labour involved in the expanding economy cannot be ignored.More than half of the labour involved in these developmental activities are migrant labour.

⚫Management of hazardous wastes

Hazardous wastes may remain dangerous for thousands of years.Tye hazardous waste include radioactive refuse, metallic compounds, organic solvents, acid asbestos, organic cyanide’s, hospital wastes, disposable medical equipments and tools.

The hazardous methods are adopted for the disposal of hazardous wastes.

⭐Landfills:There are permanent storage facilities for military related liquid and radioactive waste materials in secured lands.High level radio active wastes are stored in deep underground storage.

⭐Deep well injection:It involves drilling a well into dry,porous material below ground water.Hazardous waste liquids are pumped into the well.They are soaked into the porous material and made to remain isolated indefinitely.However fractures in the impermeable layer may permit the injected wastes to escape and contaminate ground water.

⭐ Surface impoundments:This method is used to dispose large amounts of water carrying relatively small amounts of chemical wastes.Surface impoundments are simple excavated depressions(ponds)into which liquid wastes are drained.Solid wastes settle and accumulate which water evaporates.If the pond bottom is well sealed and if evaporation equals input,wastes may be stored in the impoundment indefinitely.

⭐Incineration:The hazardous biomedical wastes are usually disposed off by means of Incineration.Human anatomical wastes,discarded medicines,toxic drugs,blood,pus, animal wastes,microbiological and biotechnological wastes etc are called Bio medical wastes.

⭐ Bioremediation:This is another rapidly developing clean up technology.Cleaning environment with biological options such as microbes and plants is called Bioremediation.Some naturally occurring bacteria and other microorganisms have the capability to degrade or absorb or detoxify the wastes such as heavy metals.

⚫ Management of non hazardous wastes

⭐ Sanitary land fills:The refuse is spread in a hollow land or in a trench and compacted with a layer of clear sand fill.The sanitary land fills are far more desirable than open dumps but the ground water contaminated is always a potential problem.Once a land fill operation has been completed the site must be inspected periodically.This land fill is suitable for recreational activities such as parks and play ground.

⭐Incineration:Municipal incinerators burn combustible solid waste and melt certain non combustible materials.Since the high temperature destroys pathogens and their vectors,it is a good method of disposal from health point of view.

⭐Reuse and recycling techniques: Resource recovery is a broad term that is used for the retrieval of valuable materials or energy from a waste.The separating out of materials such as rubber,glass,paper and scrap metal from refuse and reprocessing them for reuse is named as reclamation of waste or recycling.

Paper(54% recovery) can be repulped and reprocessed into recycled paper, cardboard,and other paper products.

Glass(20% recovery)can be crushed, remelted and made into new containers or crushes used as a substitute for gravel or sand in construction materials such as concrete and asphalt.

Some forms of plastics(2.2% recovery) can be remelted and fabricated into carpet fibre,fill for insulated apparel, irrigation drainage,tiles and sheet plastics.

Metals can be melted and fabricated (39% recovery).

Food wastes and yard wastes(leaves,grass etc.) can be composted to produce humus soil conditioner.

Textiles can be shredded and used to strengthen recycled paper products.

The Sangam Tamils had their own system of music,dance and drama(Pann,Aadal and Koothu).The Panar and Viraliyar were proffesional musicians and dancers.String instruments (Yaazh) wind instruments (kuzhal) and drums(Muzhauu) were used in such performances.Festivals and worship were also associated with dance and music(Kuravai,Veriyaattu).The pallava inscription at kudumianmalai refers to a great musician Rudracharya.

The Devaram and Divya Prabandam were set to Ragas.The puranic themes were enacted in the form of Koothu or gaathas.The Devadasis or temple servants were excellent dancers.

In the field of architecture the Sangam age did not produce enduring structures with the advent of the Pallavas a new style in art and architecture appeared in Tamilnadu.At first Mandapams were excavated out of rocks with excellent sculptural representations(Mahisasura mandapam,Varaha mandapam).Then single rocks were converted into ratha like temples(monolithic rathas at mahabalipuram).They built structural temples by filling up stone slabs(Shore temple,kailasanathar temple and vaikuntha perumal temple).These temples were noted for their Vimanas.The imperial cholas developed this style further.Elaborate campuses,protective walls,pillared halls,huge towers and multi shrines marked the chola temple architecture.The Tanjore Brihadeeswaram,Gangai Kinda cholapuram and Darasuram are outstanding specimens of chola architecture.All these temples have excellent sculptural representations.The Sittannavasal caves , kailasanathar temple and Brihadeeswarar temple have the best specimens of paintings.The chola bronze images of Nataraja,Siva,Vishnu and other dieties have earned global acclaim.

The Tamil had developed their own system of mathematics time calculation, astronomy and medical systems.

The Sangam literature refers to “Enn” kanakku Nazhigai ,Yamam kaatham and kol.They also refer to seasons as Elavenil,Elaiudir etc.References to native medicines like Elathi,Tirikadukam,Siru pancha Mulam etc reveal Tamil’s versatile achievements.Kaniyans were both astronomers and astrologers.The Tamil Siddhas produced excellent treaties on Siddha system of medicine and these treaties elaborate diagnosis, treatment by herbs and chemicals and also provide pharmacological details.

The movement in plants is mostly seen as bending, turning, twisting or as elongation of plant parts.Plants are fixed in a place with their roots in the ground.They lack the power of locomotion,but they can move individual parts or organs when subjected to external stimuli like light,water, chemical substances and touch.

These plants movements made in response to external stimuli fall into two main categories namely Tropic movements and Nastic movements.

Tropic movement

These are directional movements and are in response to stimulus,which comes mostly from one direction.The growth may be towards the stimulus or at the specific angle to the stimulus.Movement in which the direction of stimulus determines the direction of response is called tropism.

Depending on the types of the stimulus the tropic movement is classified as follows:

If the growth or movement of a plant part is towards the stimulus,it is called positive tropism.If the growth or movement of a plant part is away from the stimulus,it is called negative tropism.

⭐ Phototropism

The movement of a plant part in response to light is called Phototropism.If the plant part moves towards the sunlight,it is called positive phototropism.If the plant part moves away from the sunlight, it is called negative phototropism.The stem always grows towards light and the root always grows away from sunlight.

⭐ Geotropism

The movement of plant part in response to gravity is called Geotropism.If the plant part moves in the direction of gravity,it is called positive geotropism.If the plant part moves against the pull of gravity,it is called negative geotropism.Roots of a plant always grow downwards in the direction of gravity and the stem always grows upwards against gravity.

⭐Chemotropism

The movement of a plant part in response to a chemical stimulus is called Chemotropism.If the plant part moves towards the chemical,it is called positive chemotropism.On the other hand if the plant part moves away from the chemical,then it is called negative chemotropism.

⭐Hydrotropism

The movement of a plant part in response to water is called Hydrotropism.If the plant part moves towards water,it is called positive hydrotropism.On the other hand if the part moves away from water it is called negative hydrotropism.The roots of a plant always go towards water and they are positively hydrotropic.

⭐Thigmotropism

Climbing plants have weak stems.They cannot stand erect.They use thin thread like climbing organs called tendrils.Tendrils are sensitive to touch or contact of other objects,then the side of the tendril in contact with the object grows slower than its other side.This causes the tendril to bend towards the object by growing towards it,wind around the object and cling to it.The winding movement of the tendril of a climbing plant is an example for Thigmotropism.

Nastic movement

The movement of a plant part in response to an external stimulus in which the direction of response is not determined by the direction of stimulus is called Nastic movement.

Some of the Nastic movements are as follows:

⭐Thigmonasty

The non directional movement of a plant part in response to the touch of an object is called Thigmonasty.The best example for thigmonasty is mimosa pudica.If we touch the leaves of the sensitive plant,then its leaves fold up and droop immediately.

⭐Photonasty

The non directional movement of a plant in response to light is called Photonasty.The opening of leaves and flowers during the day and their closure at night is an example.A dandelion flower opens up in the morning in bright light but closes in the evening when the light fades and it gets dark.

⭐Thermonasty

The non directional movement of a plant in response to temperature is called Thermonasty.In crocus, the flowers open at high temperature and close at low temperature.

Any animal which becomes a source of trouble or loss to human is called a pest.Among insects such pests are numerous and are of different kinds.An insect is usually called as a pest when it causes appreciable damage and loss to the crops or other belongings.The pests may be classified as major or occasional.The insects damaging standing crops cereals, fruits and other plant products of commercial importance are designated as crop pests.Those insects destroying stored grains are called store pest.Insects causing damage to household articles are called the household pests.

⚫Pest of cotton

⭐Pink boll worm-Pectinophora gossypiella

This pest causes damage to the buds,flowers and seeds.

⭐Red cotton bug-Dysdercus koenigii

This bug sucks the cell sap of green bolls and leaves.

⭐Spotted boll worm-Earias vitella,E.insulana

E-vitella is abundant in high rainfall areas,where as E-insulana abounds in areas receiving scanty rains.The caterpillars of Earias.bore into the stem portion of young seedlings and apical shoots and later eat into buds,flowers and bolls.The attacked shoots wither,droop and ultimately die.

Control:The attacked shoots and bolls should be collected and destroyed.Avoid growing lady’s finger during the off-season in the vicinity of the cotton fields.

⚫Pests of paddy

⭐Rice stem borer-Tryporyza incertulas

This pest bores into the stems of the young mature stages of paddy.

⭐Rice bug-Leptocorisa acuta

It mainly feeds on paddy but is also found feeding on millets,maize,sugarcane and some grasses The adults and nymphs feed on the milky juice of the forming grains which as a consequence become chaff.

Control:In nurseries and fields,the leaves of paddy plants containing eggs should be clipped and burnt.As the bugs feed and breed on various types of grasses,removal of such grasses from the fields will help in reducing the population.

⚫Pest of sugarcane

⭐ Sugarcane root borer-Emmalocera depressella.

This pest causes damage to the stem below the soil surface.

⭐ Sugarcane shoot borer-Chilo infuscatellus

This pest causes damage to the shoot.

⭐ Sugarcane top shoot borer-Scirpophaga nivella
The damage by the borer actually starts from the mid rib of the top leaves into which it bores and makes tiny holes.

Control: Effective control of this pest is possible only by integrating mechanical and chemical control methids.Mechanical methods include the collection and destruction of egg masses and affected top shoots and sowing of resistant varieties.

⚫Pests of vegetables

⭐Red pumpkin beetle-Raphidopalpa foveicollis

This pest causes damage to the leaves, flowers and buds of younger plants.

⭐Brinjal shoot and fruit borer-Leucinodes orbonalis

The pest starts damaging the Brinjal plant a few weeks after its transplantation.When the shoot is attacked by the caterpillar it droops and withers, finally drying up When the petioles of the leaves are bored into by the larva the leaves wither and drop.

Control: Prompt collection and destruction of the plant parts harbouring larvae help in reducing the infestation.

⚫Pest of coconut palm

Rhinoceros beetle-Oryctes rhinoceros.The adult causes infestation by feeding the young leaf fronds.They make burrows and throw out a fibrous mass.The infestation is marked by a number of holes on the fronds,when they open out.The attack results in the destruction of growing plant as a result of which the tree dies.

Control:The beetles should be destroyed by inserting specially designed hooked rod.In earlier developmental stages beetles should be destroyed by tackling the breeding places like manure pits near gardens.

⚫Pests of stored grains

⭐Rice weevil-Sitophilus Oryzae

This is a very serious major pest of stored grains in farm storage.Generally, infestation starts in grains only during storage which may lead to heat spots in the grain.The grains are hollowed and the weight is reduced.

Control:The weevil is unable to breed at a grain moisture content of 9% or less.Hence dry storage of grains can avoid infestation by the pest.

⭐Pulse beetle-Callosobruchus chinensis

It affects both in fields and in stores.The pest attacks leguminous pods in the field from where they are carried to godowns.The larvae bore into the pulses and grains.They feed and grow inside.The damaged grains are unfit for human consumption.

Control: Control can be achieved by growing suceptible crops atleast a kilometer away from storage godowns which are the main source of infestation.

⚫ Pests of household goods

⭐Silverfish-Lepisma saccharina

It is cosmopolitan in distribution.It is commonly found living in moist warm places and among old books.It mostly attacks old books and magazines.It infects starched clothes,rayon fabrics,book labels or bindings where glue has been used.

Control:The books should not be kept in damp places.Books should be exposed to sunlight frequently.Dusting of 5% malathion has proved to be an effective control measure for heavily infested cases.

Fish farming is the raising of fish for personal income or profit Based on the environment in which culture is done.is the fastest growing area of animal food production. Today, about half the fish consumed globally are raised in these artificial environments.

Characters and cultivable fish

The following criteria should be considered before selecting a fish for farming purpose.

⭐Rate of growth:Fish which grow to a larger size in shorter period are suitable for culture.

⭐ Adaptation to climate:The cultured species of fish should be able to adapt to the local climatic conditions of the farm.

⭐Tolerance:The fish should have the capacity to tolerate wide fluctuations in the physico chemical conditions such as oxygen, salinity, temperature etc of the water.

⭐Acceptance of artificial feed:When more number of fish is to be accommodated in a limited space,there is the need for supplementary feeding on compounded diets.The fish should show ready preference for these feeds.

⭐ Resistance:It is desirable that the cultured fish is Hardy enough to resist the common diseases and attack of parasites.

⭐ Amiability and compatibility:The fishes proposed to be cultured together should be able to live together without interfering or attacking the other.

⭐Conversion efficiency:The species of fish which give more edible flesh per unit of food consumed,is preferred.

⭐Consumer’s preference:Food preference of people vary with the geographic regions Hence,the species cultured should be easily marketable locally or to the targeted consumers.

Marine fishes

Besides the food fishes,there is an enormous potential for the mass culture of a variety of ornamental fishes,which can bring in high profit,also from overseas markets.

Fish pond

A successful aquaculture practice with a good harvesting is usually due to proper construction, preparation and maintenance of the fish pond.

Types of fish ponds

Within the fish farming pond system there can be different pond components, namely nursery, rearing, production, segregation and breeding ponds.Nursery ponds are shallow, while the others are moderately deep.In larger production ponds,water can be maintained at a depth of 2 and 3 metres.A fencing around the fish farm,may be construed for protection.

Preparation of pond

Before the culturing of fish,the pond should be conditioned.

Conditioning

A layer of lime is spread over the bottom,for two weeks.It removes the acidity of the soil, facilities desirable geochemical cycles and kills unwanted soil organisms.Water may be let in slowly after two weeks and filled to the desired depth.The quality parameters such as temperature, oxygen content,pH, turbidity,hardness, alkalinity and plankton growth should be checked for their optimal levels,before stocking the fish.

Manuring

After 15 days of limiting,the fertilization is to be done in order to develop the fish food organisms.Manure may be of organic or chemical nature.

Management of fish farm

Feed and water quality are the two major factors governing the productivity of the fish culture pond.Besides,seed quality, stocking and other management measures also determine the extent of fish production.

Feeding

Apart from natural food,most cultured species take artificial feeds.In general artificial feed should contain 30-40% protein,5-10% fat,50-60% carbohydrate,less than 5% cellulose,10% water, vitamins and minerals.

Routine management and diseases

Analysing water parameters, replenishment of water, regular feeding, observation for mortality and disease symptoms should be routine checks in the management of aquaculture ponds.

A fouling organism is an animal or plant species that exists in water and attaches to the surface of a material immersed in the water. When attached to a ship’s hull, these organisms accumulate and grow to form undesirable layers of material.

Several aquatic organisms cause damages to submerged surfaces.Since this infestation has an economical importance,several studies are being made.Marine sedantary organisms may affect piles,floats,wooden dry docks and boats.These organisms are called foulers.Most of these organisms are distributed all over the world through the agency of ships.They are of economic importance,since fouling of ships results in increased resistance to movement through water, reducing the efficient, lowering of speed, increasing fuel consumption and leading to wear and tear of engine.The efficiency of underwater sound equipments fitted on to commercial and naval vessels is also seriously affected as result of the accumulation of fouling Organisms.

Pipes and conduits used to convey salt water in ships, industrial plants,oil refineries,nuclear power plants and aquaria become clogged and the flow is interrupted by the growth of these organisms inside the pipe.Thus the problem of fouling Organisms is serious.

Factors influencing the settlement of fouling Organisms

Several factors are known to influence the settlement of larvae of fouling Organisms.The most important of which is recognised to be the formation of the primary film.It is composed chiefly of diatoms and algal spores with a relatively small portion of bacteria.The thin filaments of algae may afford foothold on the substratum for the larvae to settle.The algae and diatoms serve as food for these larvae.

Members of the fouling community

The most important members of the fouling community include algae and representatives from almost all the invertebrate groups and the tunicata.Among the molluscs the mussels are the most important foulers.They settle heavily, especially in the pipe system carrying seawater and obstruct the flow of water.Aming Arthropoda, the barnacles are the dominant representatives of the fouling community.There are over 100 species of barnacles as foulers.

Prevention of fouling

⭐ Using copper sheathing on wooden hulls of boats.

⭐ Applying suitable antifouling paint.

⭐Chlorination in condenser system.

Insects affect man’s welfare in many ways.Many insects are beneficial to man.Beneficial insects are divided into two main groups according to the nature of benefit derived from them.They are Productive and Helpful insects.

⚫ Productive insects

These insects produce certain substances which are useful to humans.The important insect products are Honey,Silk and Lac.

⭐Honey bee

Honey bees are social insects.They line as colonies.They are active throughout the year.They feed on the pollen and nectar of flowers.The honey bees collect nectar from various flowers.The nectar is swallowed by the bees.In its stomach due to the action of enzymes certain changes happen to the nectar.Later in the bee hive it is collected and stored in Chambers as honey.Apiculture or bee keeping is the technique of rearing honey bees for honey and wax from their comb or beehives.

Honey has a high nutritive value.Its colour and smell varies in accordance with the nectar collected from different flowers.One gram of honey provides approximately 33k.cal of energy.It is used in Ayurvedic and Unani systems of medicines.It us helpful in building up the haemoglobin of the blood.It prevents cough,cold and fever.

Beewax is also a natural secretion of the worker bee from the glands located in the abdomen.It is used in the manufacture of cosmetics,face creams,paints, ointments, plastic works,polishes,carbon paper and many other lubricants.It is also used in microtomy for block preparation of tissues.

⭐Silk worms

Silk is another valuable product from the insect world.The silk is obtained as fine threads from the cocoons of various species of silkworms.Sericulture is the scientific management of production and marketing of natural silk from silkworms.The caterpillar of this worm feeds on castor leaves.The cocoons of this worm have very loose texture and the silk produced is called as Arandi silk locally.The threads are not glossy but much durable.

The sericulture plays a significant role in the rural economy of our country.The Chinese have the credit of discovering silk.It was kept as a secret for several centuries.

The raw silk is used in the manufacture of woven materials,knitted fabrics and garments.It is also used in parachutes, fishing lines,as sieves in flour Mills, insulation coil for telephones and wireless receivers,and tyres of racing cars.

⭐Lac insects

Another useful product we get from insects is lac.Lac is the recinous protective secretion produced by a kind of scale insect Called Laccifer lacca.The minute red coloured larva of this insect,settles on succulent shoots of the host plants.While growing they secrete a resinous material which covers them.The twigs are harvested and the encrustations scraped,dried and processed to yield the lac of commerce.

Lac is one of the most versatile natural resinous material.It has a unique combination of properties which render it useful in the plastics,epectrical,leather,wood finishing and other industries.It is a principal ingredient of sealing wax.

⚫ Helpful insects

This category of insects all forms which by their life activities help man in controlling the plant and animal pests.

⭐ Insect-Predators

These are generally larger than their prey.They can pounce upon and devour the prey easily.Amomg the insect predators,lady bird beetles are more useful to the farmers and gardeners.These small beetles are voracious and are highly prolific and long lived.Both larvae and adults feed on a wide range of insects.

⭐ Insect parasites

Insect parasites are smaller than their hosts.They live continuously for at least a part of their lifecycle on or within the body of the host.The braconids are a large group of small wasp like insects that parasitize a wide range of insects including plant lice and caterpillars.Most group of insects are plagued by ichneumon parasites.Employing insect predators and parasites for controlling the population of insect pests is known as biological control.

⭐ Insects as pollinators

Insects play an important role in the pollination of plants.Bees,wasps,ants,butterflies, beetles and thrips render valuable service in pollination.The services of honey bees are needed in the production of cultivated crops,such as apples,pears,plums and vegetables.Some plants like yucca and Smyrna fig are completely dependent upon insects for pollination.

⚫Other useful Insects

A number of insects feed on plants and they may aid in keeping plant weeds under control.The most successful use of an insect in the control of a plant was the introduction of the caterpillar of a moth to control the prickly pear.

Intake of nutrients into the body by an organism is called nutrition.All the nutrients required by organisms are obtained through the food they consume.Plants use inorganic minerals for nutrition. Complex interactions involving weathering of rock minerals, decaying organic matter, animals, and microbes take place to form inorganic minerals in soil. Roots absorb mineral nutrients as ions in soil water. 

Organisms differ in their modes of nutrition.There are mainly two modes of nutrition.

⚫ Autotrophic nutrition

⚫ Heterotrophic nutrition

⚫ Autotrophic nutrition

In autotrophic nutrition,the organism synthesizes its own food.Organisms which are able to synthesize their own food materials are called autotrophs.They convert carbondioxide and water into various organic compounds with the help of energy.Depending on how the plants obtain energy for converting Carbondioxide to organic compounds,they are classified as:

⭐ photo autotrophs

⭐chemo autotrophs

⭐ Photo autotrophs

All green plants are photo autotrophs.These are organisms which use energy from sunlight for the synthesis of food.Examples also include some bacteria like green sulphur bacteria, purple Sulphur bacteria.

⭐Chemo autotrophs

Organisms which use chemical energy for the synthesis of carbon compounds are called chemo autotrophs.They get energy by oxidizing simple inorganic compounds such as hydrogen,sulphur containing compounds, hydrogen sulphide and ammonia.E.g.Nitrosomonas bacteria.

⚫ Heterotrophic nutrition

Some organisms cannot synthesize their own food.They depend on other organisms for their food directly or indirectly.Organisms which are not able to synthesize their own food are called Heterotrophs.

Heterotrophic nutrition is of two types:

⭐ Saprophytic nutrition

⭐Parasitic nutrition

⭐ Saprophytic nutrition

Plants which obtain nutrition from dead or non living organic matter are called Saprophytes.e.g.monotropa

⭐ Parasitic nutrition

In parasitic nutrition,an organism derives its food from the body of other living organism(host).These plants are called parasitic plants.They have special structures which penetrate the host and absorb food,water and minerals.These special structures are called haustoria.eg:cuscuta

⭐ Symbiotic nutrition

When two organisms live together,they exchange nutrients and are benefited mutually.Such type of nutrition is called Symbiotic nutrition and the organisms are called symbiots.e.g.Rhizobium

Herbarium is a collection of pressed,dried plant specimens mounted on specified sheets, identified and arranged in the order of an approved and well known system of classification.It also refers to the institution where dried plant specimens are maintained and studied.

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A twig with leaves, inflorescence or flowers is collected from shrubs and trees.In the case of herbs,the collected plant specimens should contain both vegetative and reproductive parts.They are dried by keeping them between the folds of old newspapers.It is necessary to change these papers at regular intervals,until the plants are well dried.The plant specimens along with their parts are dried in a plant press.It consists of two boards with straps,which help in tightening the newspapers with specimens between the boards.

The dried specimens are pasted on the herbarium sheets of standard size 41cm X 29cm.The process of attaching dried and pressed plant specimens on herbarium sheets is known as mounting of specimens.All the mounted specimens are sprayed with fungicide like 0.1% solution of mercuric chloride.To protect these dried specimens from the attack of insects, pesticides such as naphthalene and carbon disulphide can be used.The heavy parts of plants such as seeds and fruits are kept in packets and attached to the sheets.

These specimens are called type specimens.The name of the family is always based on type genus.These specimens are most valuable part of herbarium and they are handled with special care.They are stored in fire proof cabinets.

Importance of herbarium

⭐ Herbarium is a source of knowledge about the Flora of a region or a locality or a country.

⭐It is a data store in which the information on plants are available.

⭐The type specimens help in the correct identification of plants.

⭐It provides materials for taxonomic and anatomical studies.

Because of its importance, several herbaria have been established at the national and international centres.

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Looking at the modern children,one striking difference between the childhood that the previous generation had and the one that this generation has is the lack of Indian or native games .Several traditional sports are still popular amongst kids in the urban and rural areas but they are restricted mainly to the households or neighbourhoods.

In the 1970’s, people used to play a variety of indoor and outdoor games that were the games of this soil.While some traditional sports are still being played mostly in rural areas. There are a few which have been long forgotten in this rapidly changing and evolving world.In a time of Play Stations, video games and gadgets, we all have almost forgotten the traditional games of India. 

Nowadays almost all children play games like cricket,tennis and football.Nobody is playing games like kabaddi,goli,ghilli or indoor games like dhaayakattam,paramapadham,pallangozhi,paandi or aadupuliaattam.These games have a rich culture and heritage value and were tools of passing on some ancestral knowledge or the other.

They also sharpened our observational and math skills unlike the hit and run games of the west that are uni dimensional and strengthen only hand eye coordination.

Traditional games were not just games they were designed in such a way that one can develop lot of skills like logical thinking, building strategy, concentration,basic mathematics, aiming,and a lot more.Nowadays we develop these skills by paying money to centres that conduct personal davelopment courses.Traditional games act as learning aids.They teach us many things while playing,like to learn to win and lose, develop sensory skills, count,add, improve motor skills, identify colour, improve hand eye coordination and finally to have fun,either by playing the game or watching a game being played.

The value that we achieve by playing these games are more when compared to the games that we play nowadays.Some of the values that we gain are that they are environment friendly,we get a chance to learn about our culture and history,and an important thing is,it is suitable for all ages,so they increase the interaction between generations.Many modern games played around the world have their origin in these traditional games which is a pride to our country’s culture.