We know that in ancient times, cattle were often regarded as money.
However, cattle could not be carried around easily when you went shopping, or if you wanted to trade. So, Man began to look for a more convenient way of trading. He started to use lumps of metal like iron, silver, or gold as money.
Some historians believe that the Chinese started using tiny metal knives and spades as money as early as 1000 BC. The people of Asia Minor (now in Turkey), the Greeks, and the Romans also started to use coins made of silver.
By the Middle Ages, coins were stamped by an issuing authority, and made of uniform weights so that their value could be fixed. The use of coins soon became very popular, because they were so convenient. Moreover, since the value of each coin was fixed, trade became easier too. In ancient times, artisans made every thing, including coins, using simple tools. So, the final results depended very much on skill.
Coins were either cast in a mould, or hammered out with hand held dies. The minting of coins was, therefore, a laborious process. The mint consisted of just a cluttered workshop where a master coiner and his assistants laboured away, stamping coins by hand.
They hammered the sheets of metal into the required thickness, and then, cut out blank coins with a hand punch. The blank coins were trimmed to the desired size, and stamped with a hand held die.
In the 15th century, simple machines took over from simple tools. In the 18th century, massive steam engines trans formed ingots of raw metal into thin sheets. Other steam engine powered machines cut the blank coins, and stamped them.
The movement of animals from one place to another in search of food, or to protect themselves, is known as migration.
Animals migrate because their internal clocks tell them to do so. Birds like the Siberian crane fly long distances to escape the harsh winter of their homeland, and to find food to survive.
Their internal clocks tell them that winter is approaching, and that food will be scarce. So, even before the scarcity sets in, they fly away. They stay in the new place until their internal clocks tell them that winter is over, and that they can fly home again.
Animals don’t have the internet, GPS, or even maps to find their destination. Yet each year they manage to find their way across thousands of miles of land and sea.
Pollution is aggravated thanks to four developments: increasing traffic, growing cities, speedy economic development, and industrial enterprise.
*The presence within the atmosphere of 1 or additional contaminants in such quality and for such period because it is injurious, or tends to be injurious, to human health or welfare, animal or flowers.
*It’s the contamination of air by the discharge of damage full substances.
*Pollution will cause health issues, injury the atmosphere, property and global climate change.
Major air pollutants and their sources Carbon monoxide (CO)
* It’s a colourless, scentless gas that’s made by the unfinished burning of carbon-based fuels as well as petrol, diesel, and wood.
*it’s conjointly made from the combustion of natural and artificial product like cigarettes.
*It lowers the quantity of gas that enters our blood.
Carbon dioxide (CO2) *It’s the principle greenhouse emission emitted as a results of human activities like the burning of coal, oil, and natural gases.
Chloroflorocarbons (CFC) * These area unit gases that area unit free primarily from air-conditioning systems and refrigeration.
*Once free into the air, CFCs rise to the strato sphere, wherever they are available in touch with few different gases, that cause a discount of the ozonosphere that protects the planet from the harmful ultraviolet rays of the sun.
Lead *It’s gift in hydrocarbon, diesel, lead batteries, paints, hair coloring product, etc. Lead affects youngsters specifically.
* It will cause systema nervosum injury and biological process prob lems and, in some cases, cause cancer.
Ozone *It happens naturally within the higher layers of the atmosphere.
* This necessary gas shields the planet from the harmful ultraviolet rays of the sun.
*However, at the bottom level, it’s a waste product with highly poisonous effects.
* Vehicles and industries area unit the most important supply of ground level gas emissions.
*Gas makes our eyes itch, burn, and water. It lowers our resistance to cold and respiratory disease.
* It causes air pollution and acid precipitation. it’s made from burning fuels as well as hydrocarbon, diesel, and coal.
*Pollutant will create youngsters liable to respiratory diseases in winters.
Smog • The term air pollution was 1st used (1905) by Dr H A Des Voeux
• air pollution has been coined from a mix of the words fog and smoke. Air pollution may be a condition of fog that had soot or smoke in it.
The Formation of air pollution *Chemical science air pollution (smog) may be a term wont to describe pollution that’s a results of the interaction of daylight with bound chemicals within the atmosphere.
* One amongst the first parts of chemical science air pollution is gas.
*Whereas gas within the layer protects earth from harmful ultraviolet radiation, gas on the bottom is hazard ous to human health.
* Ground-level gas is made once vehicle emissions containing gas oxides (primarily from vehicle ex haust) and volatile organic compounds (from paints, solvents, printing inks, crude product, vehicles, etc.) move within the presence of daylight.
The effects of air pollution *It hampers visibility and harms the atmosphere.
*Metabolic process issues
*Deaths with reference to cartilaginous tube diseases.
*Serious air pollution greatly decreases UV.
*Serious air pollution ends up in the decrease of natural viosterol production resulting in an increase within the cases of rachitis.
Indoor pollution *It refers to the physical, chemical, and biological char acteristics of air within the indoor atmosphere at intervals a home, or an establishment or industrial facility.
*Indoor pollution may be a concern wherever energy potency enhancements typically create homes comparatively air tight, reducing ventilation and raising waste product levels.
*Indoor air issues are often refined and don’t perpetually manufacture simply recognized impacts on health.
*Completely different conditions area unit liable for indoor air politician lution within the rural areas and also the urban areas.
Environmental effects? * If ash isn’t captured and disposed off properly, it will foul air and water significantly.
* It causes metabolic process issues.
Fly ash within the air slowly settles on leaves and crops in fields in areas almost thermal power plants and lowers the plant yield.
Measures to manage pollution *Town desires associate degree implementation strategy to
The Internet is the largest computer network in the world. It links millions of smaller networks which are connected to each other by phone lines, cables, or wireless connections.
If your computer is connected to the Internet, it can help you to get information from other computers, send messages to a friend who lives far away, or do lots of other amazing things like hear a song, or watch a famous movie.
This is possible because when you log on to the Internet, you are given access to the other computers that are also connected.
Today, people rarely write letters- they send e-mails instead. Electronic mail or e-mail, is a method of using your computer to send messages to other people who are connected to the Internet via their computers. Your message is first delivered to a computer called the mail server.
From there, it is transferred through the net, until it reaches its destination Just as you need to know a person’s address to send a letter, you have to know a person’s e-mail address to send an e-mail.
The desert rose is neither soft nor fragrant. In fact, it is not a flower at all, but a gypsum crystal. Do you know what gypsum is?
It is a mineral used in the manufacture of concrete, sheet rock, and plaster of Paris. In the desert, gypsum crystals are found in sand dunes.
The grains of sand interfere with the growth of crystals, and the result is that the crystals are formed in the shape of petals.
Desert rose gypsum is found in many locations around the world, and specimens found in different places can look radically differ ent, but all of them are without doubt delicate beauties born of the Earth.
Pollution is defined as an addition or excessive addition of certain materials to the physical environment (water, air and lands), making it less fit or unfit for all times
POLLUTANTS *Pollutants are the materials or factors, which cause adverse effect on the natural quality of any component of the environment.
*As an example , smoke from industries and automobiles, chemicals from factories, radioactive substances from nuclear plants, sewage of homes and discarded house hold articles are the common pollutants.
:Classifications
(1) consistent with the shape during which they persist after release into the environment.
*Primary pollutants: These continue the shape during which they’re added to the environment e.g. DDT, plastic. • Secondary Pollutants: These are formed by interaction among the first pollutants.
*For instance , peroxyacetyl nitrate (PAN) is formed by the interaction of oxide s and hydrocarbons.
(2) consistent with their existence in nature.
* Quantitative Pollutants: These occur in nature and be come pollutant when their concentration reaches beyond a intensity . Eg, CO2 , nitrogen oxide.
* Qualitative Pollutants: These don’t occur in nature and are man-made. E.g. fungicides, herbicides, DDT etc.
(3)consistent with their nature of disposal.
*Biodegradable Pollutants: Waste products, which are degraded by microbial action. E.g. sewage.
* Non-biodegradable Pollutants: Pollutants, which are not decomposed by microbial action. E.g. plastics, glass, DDT, salts of heavy metals, radioactive substances etc..)
(4)consistent with origin
*Natural
*Anthropogenic
*Causes of pollution
*Uncontrolled growth in human population
*Rapid industrialization
*Urbanization
* Uncontrolled exploitation of nature.
* Forest fires, radioactivity, volcanic eruptions, strong winds etc.,Pollution is defined as an addition or excessive addition of certain materials to the physical environment (water, air and lands), making it less fit or unfit for all times
POLLUTANTS *Pollutants are the materials or factors, which cause adverse effect on the natural quality of any component of the environment.
*As an example , smoke from industries and automobiles, chemicals from factories, radioactive substances from nuclear plants, sewage of homes and discarded house hold articles are the common pollutants.
:Classifications
(1) consistent with the shape during which they persist after release into the environment.
*Primary pollutants: These continue the shape during which they’re added to the environment e.g. DDT, plastic. • Secondary Pollutants: These are formed by interaction among the first pollutants.
*For instance , peroxyacetyl nitrate (PAN) is formed by the interaction of oxide s and hydrocarbons.
(2) consistent with their existence in nature.
* Quantitative Pollutants: These occur in nature and be come pollutant when their concentration reaches beyond a intensity . Eg, CO2 , nitrogen oxide.
* Qualitative Pollutants: These don’t occur in nature and are man-made. E.g. fungicides, herbicides, DDT etc.
(3)consistent with their nature of disposal.
*Biodegradable Pollutants: Waste products, which are degraded by microbial action. E.g. sewage.
* Non-biodegradable Pollutants: Pollutants, which are not decomposed by microbial action. E.g. plastics, glass, DDT, salts of heavy metals, radioactive substances etc..)
(4)consistent with origin
*Natural
*Anthropogenic
*Causes of pollution
*Uncontrolled growth in human population
*Rapid industrialization
*Urbanization
* Uncontrolled exploitation of nature.
* Forest fires, radioactivity, volcanic eruptions, strong winds etc.
Indiscriminate felling of trees as a results of urbanization, industrial enterprise, mining operations, and use of wood for domestic and alternative functions, have caused significant depletion of forests.
Causes 1) Shifting cultivation *During this follow a patch of land is cleared, vegetation is burned and therefore the ash is mixed with the soil therefore adding nutrients to the soil.
*This patch of land is employed for raising crops for 2 to a few years, and therefore the yield is modest.
*Then this space is abandoned and is left to recover its fertility, and therefore the same follow is recurrent elsewhere on a recent piece of land.
*All that’s needed for this technique of cultivation may be a set of easy tools, not high level of mechanisation.
2) Development project *The human population have hyperbolic significantly, thus with their necessities.
*Development comes just like the electricity comes, massive dams and reservoirs, birth down of railway lines and roads aren’t solely extraordinarily helpful, however they’re conjointly coupled with many environmental issues.
*Several of those comes need Brobdingnagian deforestation.
3) Fuel necessities *The increasing demand for fuel with ever growing population will increase larger pressure on the forests, which ends up in hyperbolic intensity of deforestation.
4) Stuff necessities *Wood is employed as a stuff by numerous industries for creating paper, plywood, furniture, match sticks, boxes, crates, packing cases, etc.
*Industries conjointly get their raw materials from plants like medication, scents and perfumes, resin, gums, waxes, turpentine, latex and rubber, tannis, alkaloids, bees wax.
*This exerted tremendous pressure on forest system and their unrestricted exploitation for numerous alternative raw materials is that the main reason for degradation of the forest system.
5) Alternative Causes *Deforestation conjointly results from overgrazing, agricul ture, mining, urbanization, flood, fire, pest, diseases, defence and communication activites.
How it affects? *Closed forests (based on cover level) have being di minished because of deforestation resulting in increase in degraded forests.
*Forests recycle wetness from soil into their immediate atmosphere by transpiration wherever it once more precipitates as rain.
*Deforestation leads to an instantaneous lowering of spring water level and in long reduction of precipitation.
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*Because of deforestation, this natural recycle cycle is broken and water is lost through speedy flee.
*A lot of of the mining activity in Republic of India is being disbursed in forest regions. the apparent result’s deforestation and eating away.
*Underground mining has conjointly considerably uncovered forests, as timber is employed for supporting the roofs of mine galleries.
*An oversized range of abandoned mines square measure lying in unhealthy form and square measure below in depth valley erosion resulting in degradation of the environment.
There are about 5,000 species of living mammals. They are divided into three subclasses, and about twenty-six orders. Mammals display a remarkable array of adaptations that enable them to inhabit a wide range of habitats.
They range in size from the minute bumblebee bat, which measures a mere three centimetres in length, to the magnificent blue whale, which can measure 33 metres from head to tail. The main orders of living mammals are given above.
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Of all the classes of animal life, mammals are considered the most advanced, and are probably the most popular class. They are the only animals that possess true hair, and have the capacity to produce milk.
Their superior brains, warm blood, and the way they care for their young have given them a great advantage over other animals in the struggle for survival.
The overall success of mammals as a group is due to their ability to adapt to virtually every environ ment on Earth. Although most species live on land, some have taken to the sea and air as well as underground.
Is it any won der that many scientists con sider mammals as the dominant animals of the world?
Carbon 14 is an isotope of carbon. It is present in the air, and is radioactive.
When we breathe, we take in tiny amounts of it into our body. In fact, every living thing is constantly exchanging Carbon 14 with its environment.
Once a being dies, this exchange stops. The car bon remains in the body until it decays, or becomes a fossil.
The Carbon 14 that is present in the decaying or fossilized organism gradually decreases, because of radioactive decay.
Scientists can therefore, estimate the age of a fossil by looking at the level of decay of the radioactive carbon it contains. This is known as carbon dating.
In a sense, all plants sleep, when the sun goes down, and there is no light.
Photosynthesis cannot take place when it is dark, and the plants cannot make food. They close down the stomata, and only respiration continues.
Some species of Cala thea, Ctenanthe and especially Maranta, fold their leaves, or roll their leaves up at night.
Plants don’t have a central nervous system, which is an essential regulator of sleep in humans. But they do tune themselves to a 24-hour circadian rhythm, just like you. … During the day, they soak up the sun in order to make energy through photosynthesis, a plant’s version of eating.
So, because of respiration, oxygen is utilised and carbon dioxide is continuously produced. … That is, the plants leave carbon dioxide at night. On the basis of this it is that in the night if you sleep under the tree, you will not get oxygen, which can cause breathing problem, suffocation etc.
