Gem Formation

                                                                   Gem Formation
Making Crystals
... To understand how crystals grow, it is helpful to actually make some. The simplest method is rock candy, which is crystallized sugar.
... Take a pot of water and stir in as much sugar as you can. When you see it settling on the bottom and no more dissolves, you have reached the saturation point. The water has absorbed all the sugar it can and this condition is called super-saturated.
... Next, bring the pot to boil. At boiling, the saturation level changes. The solution is no longer super-saturated and you can now add considerably more sugar. Do this; add more sugar until you again reach a super-saturation level.
... Remove the pot from the stove. As the water cools to room temperature again, the amount of sugar it can hold in suspension will return to the previous level. The excess sugar must come out of the solution and, as it does, it will crystallize.
... Hang a string in the sugar solution for the crystals to grow on. (It helps to put a weight at the bottom of the string to keep it straight.) They will not grow fast enough to actually watch them, but you can see the change every several minutes. By the time it has cooled to room temperature, the string will be covered with sugar crystals and the water will be super-saturated for room temperature. Five Requirements for
Crystallization.

1 Ingredients
2 Temperature
3 Pressure
4 Time
5 Space

... This is one of the principles of crystallization: as the temperature of a liquid drops, the amount of solid ingredients it can hold in suspension drops as well. Inside the earth, the ingredients are more complex than our sugar solution. You will actually have different minerals crystallizing from the same solution at different temperatures. Corundum might crystallize first. As the solution continues to cool, topaz might form and later quartz.
... Pressure has no affect on our rock candy, but it takes the proper combination of pressure and temperature for minerals to crystallize.
... Two other conditions are needed for crystallization, time and space. These are simple. The right combination of ingredients, heat, and pressure must last long enough for the minerals to crystallize. They also need room to grow. Obviously, you cannot grow an inch long crystal in a 3-millimeter wide cavity.


Mineral Crystallization
... The earth's crust varies from 3 miles, (5k,) thick under the seabed to 25 miles, (40 kilometers,) under continents. Under the crust is the mantle, which is approximately 1860 miles, or 3000 kilometers thick. It makes up 83% of the earth's volume.
... The mantle is composed of molten rock, called magma. In the rare occasions where it reaches the surface, we call it lava. The mantle is hottest near the center and heat currents keep it in constant motion.
... Where the mantle and crust meet, is a tumultuous zone with high pressures and temperatures. The crust is made up of several plates that float on the liquid mantle. As they run into with each other, some are pushed down; others are raised into new mountains.
... The magma is also in constant motion. Its movement and pressure are constantly acting on the bottom of the crust, creating wear and fracturing. Rocks break free from the crust and are carried away in the fluid magma. Much of this material melts, changing the chemistry of the nearby magma. Some of the smaller particles are destined to be inclusions in future gems.
... The lower surface of the crust is heavily fractured and contains numerous cavities. Fluids escaping from the magma flow through these fractures and cavities.
... It is here we find the proper conditions for crystal growth. The fluid is a chemical rich soup, which supplies the necessary ingredients. The cavities offer space to grow and the temperature and pressure are high. As the fluid moves through the crust, it cools enough for crystallization to occur. Only time is still required.
... One would think that, in geological terms, time should be more than sufficient. However, this is a highly tumultuous environment. The passages are constantly opening and collapsing. Often crystals start to form, and then the passage feeding the fluid is closed off. At this point all growth stops.
... If the passage reopens, growth will begin again. Often this on and off growth pattern is undetectable in a crystal. Other times, the successive layers of growth will have a slightly different chemical composition. When this happens, you see color zoning in the crystal.
... In some occasions, the new layers will have different orientation. This is the cause of twinning. Still other times, the new layers will not bond completely with each other. When you see parting on a star ruby, it is because the layers did not bond.
... There is nothing that says that, in the on and off growth process, the same minerals need to reform. Indeed, the temperature, pressure, and/or chemistry often vary, producing different minerals. When opening a deposit, it is common to see different minerals covering earlier layers.
... This is also one cause of inclusions. A new crystal may start to grow on an older and larger one, only to have the growth process stop. If the original crystal begins growing again, it will be over the newer ones.
... In a few unique situations, a nice quartz crystal form. Some time later, the chemistry changes and a very fine layer of, maybe feldspar, will cover the quartz. Still later, the conditions change again and the original quartz crystal grows more. The result is a phantom crystal.
... Sometimes two different minerals will crystallize at the same time. If one takes off and starts growing faster, it will engulf the other. This is how pyrite crystals end up inside emerald.
... In still other conditions, there will be chemical impurities within a crystal. If the temperature and/or pressure change, the impurities can crystallize inside the host crystal. This is how rutile forms in quartz and corundum.
... During the rough and dramatic changes in the crust, many crystals are broken. If the conditions for growth are present, material will seep into the fractures and crystallize, "healing" the fracture by growing back together. However, they never heal completely and fine cavities of gas remain in the previous gap. We see these as fingerprints and this is why they are also called "healing fractures."
... There are tremendous pressures in the crystal growth environment. Many crystals are compressed beyond their natural size.

You can see this in a polariscope. Many gems show strain, as rainbows of color. Sometimes this causes stress fractures.
... Strain also makes leaves stone subject to breakage. Many faceters have placed a stone on a lap, only to have it shatter. The forces inside the stone literally cause it to explode.


Getting Specific
... Mineral creation is now fairly well understood. Advances in geology and synthetic gem manufacturing have unraveled many of nature's mysteries.
... Traditionally, we were taught that there are three kinds of rock formation; igneous, metamorphic, and sedimentary. Igneous minerals are created with heat. They are minerals that are created deep within the earth. Metamorphic refers to conditions where heat and pressure change existing minerals into something new. Sedimentary rocks are based on deposits of sediment.
... Today, geologists prefer to describe rock formation as four processes: molten rock & associated fluids, environmental changes, surface water, and gems formed in the earth's mantle. Not that mineral creation is simple and straightforward. They are continuously being destroyed and recreated as in the "Rock Cycle" chart below.


Molten Rock & Associated Fluids
... Technically, gems rarely form in the magma itself, but rather from fluids that escape from it, (pegmatites and hydrothermal.) The two exceptions to this are called magma and gas crystallization.


Magma Crystallization
... Magma contains a variety of elements. As it cools, the elements combine to form minerals. Exactly what mineral is created varies with the available ingredients, temperature, and pressure. Each time one mineral forms, the available ingredients change. Different minerals form as it goes through the various stages of changing temperature, pressure, and chemistry.
... Unless the conditions are just right, crystals will not form. Instead, it will simply cool into a solid mass of small, interlocking crystals; what gemologists call an aggregate.
... In some occasions, one mineral will crystallize nicely. Then, before any more crystals can form, the magma will find a break in the crust and rust towards the surface. Here the pressure and temperature are too low to allow crystallization. Instead, the rest of the magma cools into fine-grained rocks, with the original crystals distributed through out the interior. These are called phenocrysts.
... Corundum, moonstone, garnet, and zircon are often found as phenocrysts. The Chantaburi and Trat districts in Thailand have large deposits of ruby and sapphire phenocrysts.
... Diamonds crystallize at temperatures higher than other minerals. Scientists now believe that they may form in the magma, near the earth's crust where it is the coolest. If this is true, it also means that conditions for diamond crystallization are the most common in the earth. Diamonds may actually be the most plentiful crystals in the earth, just not the easiest to reach.


Gas Crystallization
... Have you ever wondered why some crystals are doubly terminated, where most are broken off at the base? Most crystals grow on a solid base of other minerals. However, a few actually grow inside gas bubbles!
... These gems form after the magma has reached the surface. During a volcanic eruption, rising magma undergoes a rapid reduction in pressure. This causes gas bubbles form, just like removing the cork from a bottle of champagne.
... Sometimes these bubbles will contain high concentrations of certain elements. If the right combination of temperature and pressure exist for a long enough time, crystals form. Garnet, topaz, and spinel also form this way.
... One of the best known examples of gas crystallization are "Herkimer Diamonds," the water clear quartz crystals from Herkimer, New York.


Hydrothermal
... As the name implies, hydrothermal involves water and heat. As water percolates through the earth, it dissolves minerals, just as it did with the sugar in our rock candy. Deep inside the earth, it meets with magma. Special fluids then escape from the magma that contain water, carbon dioxide and volatiles, (substances that give off gasses.)
... These hydrothermal fluids move through fractures in the crust. Along the way, they may dissolve minerals, or combine with other ground water. Mineral rich, they begin to cool in "veins." If combined with the right combination of temperature, pressure, time, and space, crystals form.
... Hydrothermal deposits are special, because they can have combinations of elements not found elsewhere. One of the most important hydrothermal deposits is the Muzo emerald field in Colombia


Pegmatites
... Sometimes magma in the upper part of the mantle becomes concentrated with volatiles. This volatile rich magma is sometimes forced into a cavity where it cools. This is the definition of a pegmatite. It differs from a hydrothermal vein, in that magma is the primary agent, rather than water.


Environmental Changes
... Great stresses exist inside the earth. Under the right conditions, the temperature and pressure can rise to the point where existing minerals are no longer stable. Under these conditions, minerals can change into different species without melting. This is known as metamorphism.
... There are two types of metamorphism, contact and regional.



Contact Metamorphism
... Contact metamorphism occurs when magma forces its way into an existing rock formation. Under the intense heat, existing rocks begin to melt and eventually recrystallize as new species that are stable at higher temperatures.
... Sri Lanka is one of the best known sites of contact metamorphism. Garnets, corundum, and spinel are also common here. Lapis lazuli, which in found in the mountains of Afghanistan, is another stone created by contact metamorphism.


Regional Metamorphism

... Regional metamorphism takes place on a much broader scale and affects a much greater variety of minerals.
... The earth's surface is composed of large pieces, called "continental plates." Looking at them from a geological time frame, they are floating on the mantle and in motion. However, they do not all move in the same direction and some of them are actually competing for the same space. Where these huge structures are forced together, one is shoved under and the other is pushed up. This is our primary mountain building method.
... Enormous compression forces exist where these land masses come together, creating an area of intense heat and pressure. As the temperature approaches the melting point of rock, the minerals become unstable. Over time, (possibly millions of years,) they change into new varieties.
... East Africa is an excellent example of regional metamorphism. Minerals are found here that do not exist anywhere else. Tanzanite is a prime example, as are the unique varieties of garnet.Polymorph
Minerals that
share the
same chemistry,
but have different
crystal habits.

Pseudomorph
Minerals that
have changed
chemistry without
changing crystal
form.

... During metamorphism, some minerals simply change habit. The same ingredients recrystallize in a new crystal system, as a new species. (Remember that a mineral is defined by a combination of its chemical make up and its crystal habit.) These are called polymorphs.
... For example, andalusite, kyanite, and sillimanite all have the same chemistry, Al2SiO5. They regularly polymorph by changing into other crystal systems.
... Other crystals will change chemistry during metamorphism. They may recrystallize in their customary habits and show no abnormal properties. However, sometimes a crystal will change chemistry without recrystallizing. These unique minerals are called pseudomorphs. A pseudomorph is an atom-by-atom replacement of one mineral for another, without changing the original mineral's outward shape.
... A prime example of a pseudomorph is tigers eye. Crocidolite has been replaced by quartz, but they retain the fibrous structure of crocidolite. Marcasite has pseudomorphed pyrite, gypsum, fluorite, and goethite. Malachite frequently pseudomorphs azurite, leaving a perfect azurite crystal shape that is composed of malachite.


Surface Water
... Rain plays an important roll in recycling minerals. Erosion breaks down rocks and moves them to new locations. Once on the ground, rainwater is instrumental in creating new gems.
... As water passes through the earth, it picks up chemicals that turn it into a weak acid. If heated, or mixed with the right chemicals, it can become highly corrosive. That gives water the ability to dissolve even more minerals.
... As water percolates through the earth, it picks up many ingredients. At times, it becomes too saturated to carry any more, so it leaves the excess in cracks and pores of existing rocks. This is how fossils and petrified wood are created.
... In other conditions, the water encounters combinations of minerals that create a chemical reaction. The dissolved minerals are then deposited as new minerals in seams and cavities. This is how opal, turquoise, azurite, and malachite are created.
... During the cretaceous period, much of central Australia was covered by an inland sea. When it dried, it left the area layered with silica rich sands. For millions of years, rain has been dissolving the silica. During the hot, dry summers, the ground water evaporates to the point where the remaining water cannot hold the silica in suspension. The excess is deposited in seams and cavities, not far below the surface. These silica deposits are opal.
... Turquoise, azurite, and malachite all receive their color from copper brought by water. The copper rich water must pass through limestone to create azurite or malachite. Turquoise requires that the water also picks up some phosphorous along the way.

...


Gems Formed in the Earth's Mantle
... Knowledge of the earth's mantle is still rather limited. However, the evidence shows that some gems actually form in the mantle. To do so, they need to crystallize at an extremely high temperature.
... The most notable examples of gems formed in the earth's mantle are diamond and peridot. By studying the peridot deposits in Arizona, geologists now believe they were created on rocks floating in the mantle, approximately 20 to 55 miles below the surface. An explosive eruption brought them near the surface of the earth. Weathering and erosion finally brought them close enough to the surface for people to find them.
... Diamonds are better understood. As mentioned before, diamonds actually crystallize in the magma below the crust. However, the magma formations they are found in have a different chemical composition. It is believed to come from greater depths, 110 to 150 miles below the surface. At this depth, the temperatures are higher and the magma is very fluid.
... This hot and fluid magma has the ability to force its way through the earth's crust faster and more violently than other volcanic eruptions. During the eruption process, it will break up and dissolve rocks from the lower mantle, and then carry them to the surface.
... If the magma rose slower, the diamonds would probably not survive. The changing temperatures and pressure would cause them to vaporize or recrystallize as graphite. It is believed that the speed of the magma rise is so quick they do not have the time to transform.



1 Magma pocket comes in contact with a weak area in crust.
2 A quick explosion results, carrying diamond-bearing magma to the surface. During the eruption, a cone builds on surface.
3 The pipe eventually cools, leaving carrot shaped pipe.
4 The cone quickly erodes away, (geologically speaking,) leaving the diamond bearing earth where people can reach them.


Coming Up
... Since crystals form so far under the surface, you may be wondering how they get to the top where people can mine them. A few crystals are brought to the surface during volcanic eruptions, as described above. However, most reach the surface through mountain building and erosion.. Over vast periods of time, the movement of the continental plates causes mountains to rise.... Years of weathering take down the mountain, leaving the deposits near the surface.

Barbarians VS Vegans.

THE DANGERS
OF MEAT CONSUMPTION

High meat consumption and the expanding use of grain as feed can cause damage in the human realm. Medically, nutritionists believe that a diet rich in animal products contributes to a variety of maladies. Economically, middle-income developing countries that have attempted to provide urban dwellers with cheap meat too often have given the rural landless short shrift, while devoting growing shares of trade earnings to pay for imported feed. And socially, modern grain-based livestock production has become a major industry controlled by a handful of firms--driving small producers out of the market.

The Great Protein Fiasco:

The adverse health impacts of excessive meat-eating stem in large part from what nutritionists call the "great protein fiasco"--a mistaken belief of many Westerners that they need to consume large quantities of protein. This myth, propagated as much as a century ago by health officials and governmental dietary guidelines, has resulted in Americans and other members of industrial societies ingesting twice as much protein as they need. Among the affluent, the protein myth is dangerous because of the saturated fats that accompany concentrated protein in meat and dairy products. Those fats are associated with most of the diseases of affluence that are among the leading causes of death in industrial countries: heart disease, stroke, and breast and colon cancer. (Lipton 1983; WHO 1990; Kummer 1991; Pimentel et al. 1991; NRC 1989)

The U.S. National Research Council, the US Surgeon General, the American Heart Association, and the World Health Organization are among the organizations now recommending low-fat diets. From the current US norm of 37 percent of calories from fats--typical for Western nations--they recommend lowering fat consumption to no more than 30 percent of calories. (NRC 1988; Byrne 1988)

Recent scientific findings indicate that even that level may be too high. One study of 88,000 American nurses found daily red-meat eaters are two-and-a-half times as likely to develop colon cancer as near-vegetarians. Based on these findings, Walter Willett, director of the study and a researcher at Brigham and Women's Hospital in Boston, commented, "the optimum amount of red meat you eat should be zero." (Willett et al. 1990; Kolata 1990)

A Landmark Study of Diet and Health:

A landmark study of diet, lifestyle, and health in China--the largest such survey ever conducted--suggests that lowering fat consumption to 15 percent of calories prevents most cases of diseases of affluence. This study, known as the China Project, a joint effort of Chinese, British, and American institutions, tracked the diets of thousands of Chinese in dozens of countries. It showed that as fat consumption, protein consumption, and blood cholesterol levels rise, so does the incidence of heart disease, diabetes, and certain cancers. (Junshi et al. 1990; Vines 1990)

Surprisingly, Chinese villagers on low-fat, low-meat diets also suffered less anemia (iron deficiency) and osteoporosis (a bone disease associated with calcium deficiency) than their urban compatriots eating more meat. Both conditions are commonly thought to result from a diet too low in animal products. Study co-leader Colin Campbell of Cornell University told the New York Times: "We're basically a vegetarian species and should be eating a wide variety of plant foods and minimizing our intake of animal foods." (Junshi et al. 1990)

Squandering Resources:

If a diet rich in animal products is not an appropriate goal of public health policy, neither is it a wise development strategy. It creates dependence on imports for food and can widen the gap between rich and poor. Yet dozens of middle-income countries import livestock feed.

For a poor country where people eat few animal products, reaching self-sufficiency in food grains requires just 200 kilograms of cereals per person per year. But that number quickly rises when people switch from a grain-based diet to a meat-based one. Rapidly industrializing Taiwan, for instance, increased per-capita consumption of meat and eggs sixfold from 1950 to 1990. To produce those animal products required raising annual per-capita grain use in the country from 170 kilograms to 390 kilograms. Despite steadily growing harvests, Taiwan could only keep up with the demand for feed by turning to imports from abroad. In 1950 Taiwan was a grain exporter; in 1990, the nation imported, mostly for feed, 74 percent of the grain it used. (Vocke 1986; Sarma 1986; Bailey 1990; USDA 1990)

Mainland Chinese are following the Taiwanese up the meat consumption ladder. Since 1978, when agricultural reforms boosted production, meat consumption has more than doubled to 24 kilograms. The growth has been particularly marked in cities, where the government has helped create pig and poultry plants using Western-style grain-feeding technology. Though the country's farmers have been able to grow sufficient feed grain for the swelling meat industry so far, few observers expect them to keep pace for much longer. The share of Chinese grain fed to livestock rose from 7 percent in 1960 to 20 percent in 1990. (Bishop et al. 1989; Bailey 1980)

An Appetite For Economic Problems:

China's agricultural future may resemble that of the former Soviet Union, where rising meat consumption created economic problems. From 1950 to 1990, meat consumption tripled and feed consumption quadrupled. Use of grain for feed surpassed direct human consumption in 1964 and continued to rise. In 1990, Soviet livestock were eating three times as much grain as Soviet citizens. Grain imports had soared, going from near zero in 1970 to 24 million tons in 1990 (the world's second-largest grain importer). (USDA 1989,1990,1991)

In the Middle East and North Africa, grain-fed livestock operations are proliferating, boosting the demand for imported feed. The richest Middle Eastern countries match Western levels of meat consumption by depending heavily on imported feed and meat. Egypt, the poorest country in the region, is also a major grain importer, partly due to rising grain-fed meat consumption in the cities. Since 1970, grain imports have risen from near zero to 8 million tons per year. (USDA 1990)

Middle-income Arab nations, such as Syria, also have seen rising meat consumption and soaring feed demand. The area in Syria devoted to barley for feed increased from 300,000 hectares in 1950 to almost 3 million hectares in 1989. Much of the expansion occurred on the country's dry steppes, which are ecologically suited only for grazing. Farmers in traditional barley-growing areas, meanwhile, are heeding government advice to plow under soil-conserving fallow fields for continuous barley cropping. Yet neither the addition of new land nor the switch to single-crop production has sufficed to keep up with feed demand; Syria, in 1965 a barley exporter, now imports the cereal. (Treacher 1991; Cooper & Bailey 1991)

In other countries, the pattern is more complicated. Mexico, for example, despite its colossal debt burden, continues importing corn and sorghum. Indeed, Mexico generally imports between one-fourth and one-third of the grain it consumes. Imported sorghum is used as feed, while imported corn is used as food. But the need to import corn is partly a consequence of shifts in Mexican agriculture from growing corn to growing sorghum for feed. (Barkin & Dewalt 1988; USDA 1988)

What is true for many developing countries individually is also true of them collectively. On balance the Third World exported grain until the early sixties; by the late seventies, it was consistently importing cereals. The change came not from just growing populations but also from exploding livestock industries. The FAO reports that 75 percent of Third World imports of so-called coarse grains--corn, barley, sorghum, and oats--fed animals in 1981. Little has changed since. As US Department of Agriculture trade specialist Gary Vocke writes: "Imports of corn and sorghum [for feed] have outpaced domestic production, leading developing countries to a lower level of self-sufficiency--a trend that will accelerate as livestock feeding expands in the next 10 years. (USDA 1990)

Meat Consumption Among The Affluent, at the Expense of the Poor:

Higher meat consumption among the affluent frequently creates problems for the poor, as the share of farmland devoted to feed cultivation expands, reducing production of food staples. In economic competition for grain fields, the upper classes usually win. In Egypt, for example, over the past quarter-century, corn grown for animal feed has taken over cropland from wheat, rice, sorghum, and millet--all staple grains in Egypt. The share of grain fed to livestock rose from 10 percent to 36 percent. (Barkin et al. 1990; Barkin 1991)

Likewise, the area in Mexico planted to corn, rice, wheat, and beans, the staples of the Mexican poor, has declined steadily since 1965, while area planted to sorghum has grown phenomenally. From the mid-sixties to the mid-eighties, sorghum expanded from 2 percent of grain land to 16 percent, as corn fell from 83 percent of grain land to 69 percent. Sorghum, grown mostly on irrigated, mechanized commercial spreads, is now Mexico's second-ranking crop by area. The grain is used to raise chicken and pork for urban consumers. In total, Mexico feeds 30 percent of its grain to livestock, although 22 percent of the country's people suffer from malnutrition. (Barkin & DeWalt 1988)

The share of cropland growing animal feed and fodder in Mexico went from 5 percent in 1960 to 23 percent in 1980, a transformation agriculture analyst David Barkin of the Autonomous Metropolitan University in Mexico City refers to as ganaderizacion ("livestockization") of the Mexican countryside. He sees the trend outside of Mexico as well. In Peru, for example, pastures have replaced potatoes, and feed corn has replaced staple corn. (Barkin & DeWalt 1988)

With two colleagues from the United States, Barkin examined agricultural developments in 24 Third World countries. They found clear evidence in 13 countries that farmers were switching from food crops to feed crops; in eight of them, farmers had shifted more than 10 percent of grain land out of food crops in the past 25 years. Worse, Barkin and his colleagues concluded that, at least where data were available--Brazil, Columbia, Egypt, Mexico, Peru, the Philippines, South Africa, Thailand, and Venezuela--the demand for meat among the rich was squeezing out staple production for the poor. (Barkin et al. 1990)

Industrial Farming at the Expense of Small Farms:

Beyond its effect on food security for the poor, grain-fed intensive production--because it is essentially an industrial operation--tends to create inequities within agriculture. In traditional production, animals play an equalizing role in agriculture. Because grass, crop wastes, and other fodder are widely dispersed, they are best utilized by small farms. Indeed, in most developing countries animals are more evenly distributed among agricultural families than land. By contrast, ownership of grain-based livestock production tends to concentrate in ever-fewer hands, because grain readily lends itself to economies of scale. The larger the operation, the lower the overhead costs per animal, and the cheaper the product. (Lipton 1988)

In most countries, even as meat output rises, the number of livestock producers falls. Animal farms keep growing in size and dwindling in number. The number of Japanese pork and poultry firms fell by two-thirds between 1965 and 1987. Thailand's chicken industry made a similar transition in the first half of the seventies. Likewise, five firms control 75 percent of Brazil's commercial poultry production. (Bishop et al. 1989)

In the United States, where beef cattle are raised on grass for a year before going to the feedlot, the industry's profile reflects the concentrating power of grain feeding. More than a million farms and ranches raise young beef cattle, but four companies slaughter nearly 60 percent of them. Since 1962, the number of large American beef feedlots (those capable of holding 16,000 head of cattle) has risen from 23 to 189, while the number of small feedlots (those holding no more than 1000 head) has dropped by 117,000. The same pattern applies to the US pork and poultry industries. Together, three poultry companies now produce nearly 40 percent of broiler chickens, and the number of pig farms has declined by 85 percent since 1950. (ITC 1990; Charlier 1990; Martinez 1991)

The Sprawl of Animal Agriculture:

Ranch-based livestock production also fosters inequality between agriculturists in Latin America, where ranches expand at the expense of forests and arable land. Ranches create few jobs for this region's numerous jobless rural workers, employing just one person per 1,500 hectares on typical spreads in the Brazilian Amazon. Indeed, in Latin America, no other major type of agriculture enterprise creates fewer jobs per hectare than ranching. In Central America, ranchers have expanded not just into forests, but also into fertile land more appropriate for crops. In 1950, 35 percent of Costa Rica's arable farmland was in pasture; in the early nineties, the figure was 54 percent. As much as two-thirds of the rich farmland along the Pacific coastal strip of Central America is pasture. (Hecht 1990; Annis 1990; Leonard 1987)

The sweeping advance of ranching into forests in Latin America cannot be explained by the profitability of beef production. Real estate speculation is the overriding motive. In Latin America's forest frontier zones, where land is up for grabs, the value of cattle is dwarfed by the value of the earth under their hooves. When roads come through, or when minerals are discovered nearby, land values can skyrocket. An entire industry has emerged around leveling forests for pasture, selling the land for a quick profit, the repeating the venture. (Hecht 1990; Fearnside 1989)

For the land speculator, cattle ranching is simply the cheapest way to claim property: it takes little investment or labor, and states recognize pasture as the kind of "productive" land use to be rewarded with a property title. States also bypass ranches in land reforms, which distribute idle and "unproductive" lands to the dispossessed. Where inflation rates are high, as in much of Latin America, urban investors are especially keen on buying assets that retain their value, such as land. (Hecht 1990)

Closing Remarks:

The problems with animal agriculture mostly fall in the category of "too much of a good thing." Too much meat consumption leads to illness. Too much meat production leads to dependence on grain imports, a food system skewed against the poor, and a worsening environmental predicament. All the same, if livestock production is linked to a profusion of problems, the root causes of those problems are found in human institutions. Indeed, the livestock industry's shortcomings are faithful reflections of deeper faults in human societies.







                                        VEGETARIAN BENEFITS..
Vegetarians are people who avoid all meat, meaning red meat, seafood and poultry. They do this for a variety of reasons such as being humane to animals and for other ethical reasons, but most vegetarians avoid these foods because the alternatives, which are mostly herbs, veggies and fruits, have more vegetarian health benefits. Vegetarian diets can just be as enjoyable as foods with meat despite popular belief.

Healthy Heart

The greatest of the vegetarian health benefits is reduced risk of heart attacks. This is because vegetarians usually have lower cholesterol levels. Cholesterol levels are greatly increased by meat, especially red meat. Vegetarian diets are also low in saturated fats that are common in meat. Vegetables contain plant proteins, which are lower in cholesterol compared to animal proteins. Cholesterol and saturated fats are the major causes of heart disease, especially in those in their sunset years. This is because they clog the inside of the blood vessels over time. This leads to heart attacks, strokes and other cardiovascular diseases. Fruit and vegetable specifically have vegetarian health benefits by reducing the risk of getting ischemic heart disease, myocardial infarction and angina which are common in older people. This is because fruits and vegetables contain folic acid, carotenoids, dietary fiber, potassium, flavonoids, magnesium, phytosterols, and other polyphenolic antioxidants that have vegetarian health benefits.

Vegetarian diets rich in soluble fiber such as the ones found in oats, squash, carrots, dry beans and apples lowering serum cholesterol levels that might have been accumulated over the years, therefore adding people more years among other vegetarian health benefits. Fruits, nuts, whole grain and vegetables have flavonoids that have some biological properties and other vegetarian health benefits that are responsible for reducing the risk of cardiovascular disease in that they are antioxidants and so they protect LDL cholesterol from undergoing oxidation, effectively inhibiting formation of blood clots in the arteries and other blood vessels. The flavonoids also have a hypolipidemic effects and an anti-inflammatory effect – these are good for the health of the heart.

Lower Blood Pressure

Another of the vegetarian health benefits is that vegetarians have lower blood pressure compared to those who eat meat, especially red meant. This is because vegetarian diets are low in salt – salt has been identified as the main cause of high blood pressure and hypertension. High blood pressure also occurs when blood tries to flow faster because of obstructed blood vessels. The obstruction is usually caused by cholesterol ingested from eating meat. Lower blood pressure is also maintained by the potassium which is found in fruits and vegetables such as apricots, papaya, bananas, cantaloupe, strawberries, eggplant, avocado, oranges, tomatoes, cucumber, cabbage, cauliflower, bell pepper, squash, turmeric, broccoli, parsley, spinach and lima beans among others.

Control of Diabetes

Although diabetes does not have a cure yet, eating a vegetarian diet that is high in fiber and complex carbohydrates found in plant foods controls diabetes and has other vegetarian health benefits. Most doctors agree with this fact and advise their patients to consume legumes, vegetables, fruits and whole grains for controlling diabetes. These also have lower blood sugar and they completely eliminate the need for meds in some cases.

Prevention of Cancer

Another of the vegetarian health benefits is that it vegetarian diets help in the prevention of cancer which is very important because cancer has no cure. Almost all cancers, especially epithelial cancers, can be prevented with regular consumption of fruits and vegetables. Foods such as cruciferous vegetables, herbs and fruits have cancer-protective phytochemicals such as flavonoids, carotenoids, ellagic acid, sulfide compounds, isoflavones, isothiocyanates glucarates, phenolic acids, phthalides, phytosterols, saponins and terpenoids among others.

Elimination of Toxins from the Body

Meat usually has a lot of toxins. Fruits and vegetables do not have preservatives as is the case with most packaged and/or processed foods. Vegetarians usually ingest organic foods that are grown without the chemicals responsible for toxin build-up in our bodies such as pesticides. Toxins cause skin problems, allergies, influenza, and a host of other ailments. In severe cases, they have been known to cause cancer and other serious medical conditions such as infertility.

Easier Digestion of Food

It is a fact that human beings have a challenging time digesting meat and fish. These are ‘heavy’ foods that take a lot of time and energy to digest. People who eat such foods eventually experience weakening of their digestive systems which brings such problems as inability to eliminate waste rapidly. This means their bodies have a hard time doing ‘self-cleaning’ and this leads to problems such as stomach and intestinal cancer. On the other hand, foods such as fruits and vegetables are easily and rapidly digested and other vegetarian foods that are rich in fiber have vegetarian health benefits in that they actually aid in digestion.

Improvement of Overall Health

Vegetarians enjoy many health benefits and they are less likely to be obese, their skins and other excretion systems work better and they have fewer toxins in their body. Although these vegetarian health benefits might not prevent diseases directly, it is easier for vegetarians to live longer and to have less sick days.

The trophic levels & the food chain.!!

TROPIC LEVEL

The different feeding level of organisms in an ecosystem are called tropic level.Producers make the first tropic level in all ecosystem.Because they make their own food,producers are called autotrophs. Autotrophs are the sole point of enter for new energy into the ecosystem.Consumers form the second and higher tropic level in the ecosystem.Because they cannot produce their own food and must obtain nourishment by eating other organisms, consumers are called hetetrophs.Primary consumers that eat producers form the second tropic level and secondary consumers form the third tropic level.Omnivores and decomposers  feed  at all tropic level.Each tropic level depends completely on the level below it.

 Food chain & food web.

The feeding relationship among organisms at different tropic level form a chain, the food chain.A food chain may be defined as a series o organisms that transfers food between the tropic level of an ecosystem.All food chain begin with producers which are usually plants in an ecosystem.The food chain continues to herbivorse at the next tropic level,followed by one or more level of carnivorse ,the carnivorse are consumed by decomposers .And example of food chain is shown below.

 

No ecosystem is simple enough to be represented by a simple food chain.As most consumers feed on more then one type of food and some consumers feed on more then one tropic level.A food web is a network of food chain representing the feeding relationship among the organisms in an ecosystem.An example of food web is given.

 

The passage of energy in on way direction in an ecosystem is known as energy flow.In an ecosystem energy flow occurs in food chain.In which energy from food passes from one organism into the other in sequence.
Energy from the sun enters an ecosystem when producers uses the energy to make matter through photosynthesis.Consumers take in this energy when they eat producers or other consumers.In this way energy moves on from one tropic level into the other.At each tropic level some energy is lost as heat due to some activities of organisms like keeping the body warm or other physical activities.The energy  which dissipates into the atmosphere cannnot be used in the next tropic level.Only energy used to make biomass is available. 

ECOLOGICAL PYRAMIDS 

Ecological pyramids shows the relative amount of energy in an ecosystem.Each ecological pyramid is divided into sections each section represent one tropic level.An ecologist pyramid can indicate the total biomass,number of organisms,and number of organisms in a food web.

PYRAMIDS OF NUMBER..

The pyramids of number show the total amount of of organisms in each tropic level in an ecosystem.Each successive tropic level is occupied by fewer organisms.Such that the number of zebra and other wild beast is greater then carnivores such that lion. 

 

PYRAMIDS OF BIOMASS..

The pyramids of biomass represents the total amount of biomass at each tropic level.Biomass means the total amount of matter at each tropic level.The pyramids of biomass allow a progressive amount of reduction at each tropic level.

  

 

PYRAMIDS OF ENERGY..

The pyramids of energy represents the total amount of energy contents in the biomass of a tropic level.This pyramids represents that the total amount of energy that reach the next successive level is almost least as compare to the level below it.

 

HEALTHY AND GOOD FOOD FOR 

HUMAN ..

As most people have a miss concept that vegetarians have less energy or strength as compare to the meat eaters.But if we look closely the first energy contents that enters into the ecosystem are consumed by the producers and then consumers eat producers in order to obtain energy.And we in return eat the consumers to obtain energy.So why don't we directly obtain it by consuming producers??

"DNA"The genetic material.

DNA deoxyribonucleic acid.
 DNA is a genetic material.It is a long material about 2 nm thick.It runs continuously within each chromosome.DNA is acidic in nature.






THE CHEMICAL COMPOSITION OF DNA.

DNA is a complex macro molecule.The repeating sub units are called as nucleotides.Each deoxyribonucleotide are made up of
1.A phosphate group.
2.A deoxyribose sugar.
3.A nitrogenous base.

There are\ four different nitrogenous bases.ADENINE (A),GUANINE (G),THYMINE (T),CYTOSINE (C).Adenine and Guanine are larger double ring bases called PURINES..

ADININE

 

 

 Cytosine and Thymine are smaller single ring bases called PYRIMIDINES.

cytosine

 

 All of this four types of nucleotides join to form a polynucleotide chain of DNA molecule.

STRUCTURE OF DNA

JAMES WATSON AND CRICK MODEL.

 In 1953 James watson and Fransis crick gave the model of structure of DNA.They proposed that the DNA molecule is made up of two polynucleotide strand which are twisted around each other in the form of a double helix.The double helix looks like a spiral staircase of uniform diameter.

The railing of this staircase are composed of deoxyribose sugar and phosphate group.

And the steps are made up of nitrogenous bases.Each step consist of purine paired with pyrimidine.Their pairing is highly specific.Adenine pairs with Thymine and two hydrogen bonds are formed between them.While thymine always pairs with thymine and three hydrogen bonds are formed between them.

The two strands of DNA are complementary to each other.I the sequence o bases in one strand is known the sequence of bases in other strand will be automatically known.This property o the two strands of double helix makes DNA a unique molecule best suited to store ,copy.and transmit genetic information from generation to generation.Genetic information is nothing else but the base sequence of DNA in a linear order.

GENES

Genes are short lengths of DNA.

 

Protein are made in special cells under the instruction of genes.Genes sit like a boss sited comfortably on the chromosome in the office the nucleus they get their job done through their manager RNA's.

 

RNA is ribonucleic acid.It is also a polynucleotide but its bases are ribonucleotide.It consist of a phosphate group ribose sugar and nitrogenous bases.Its nitrogenous bases are ADENINE,GUANINE,CYTOSINE and URACIL.DNA controls synthesis of RNA.

Genes express itself in two ways.

1.Transcription

2.Translation.

Copying of DNA encoded information into RNA encoded information is called transcrition.

Translation is decoding of mRNA information into sequence of amino acids in a protein.

The transmission or traits from parents to offspring are called HEREDITY.

The same gene pair are known as alleles.M utation in gene pair my give rise  to many alternate form of genes.They may give rise to changes in phenotype and genotype of an individual.More over DNA also replicates because it is an heredity material.Each free strand is known as template.   

Many diseases are also passed on from generation to generation in genes.Diseases like ANAEMIA,DIABETES,COLOUR-BLINDNESS,HAEMOPHILLIA etc are transmitted from generation to generation.

More in such cases genes can be transplanted with the help of vectors.The most commonly used vector is Plasmid.

  

Transgenic plants and animals are being made by introducing desired foreign gene into them.Some of the common examples areherbicide resistant cotton,soyabean,potatoes,Transgenic animals are normally designed to improve meat yield. Common examples are sheep,goat,and cow.

   

The atomic structure.

The most small but complex structure,which give rise to every material is the atom.An atom is very complicated in its structure but it is the fundamental concept of life and elements and every material.












It is very small in its size,its size is about 0.2 nm.We can just imagine that a single full stop consist of about 2 million atoms.It can't be observed by humans eye neither by an ordinary eye microscope,but in order to study the structure of an atom we need to use an electron microscope which throws beams of electrons instead of light as the wave length of electrons is smaller then light so we can clearly identify its structure.An atom is further composed of electron,proton,neutron,hypron,neutrino,anti-neutrino etc.More then 100 such particles are thought to be existing in an atom.Further different atoms consist of dirrerent atomic masses and different atomic numbers.The atomic number and atomic masses depends upon the total number of proton and neutron present in an atom.

Every material thing in this universe are of the composition  of atoms.Water which covers about 75% of the earth surface also is composed of hydrogen and oxygen which is bonded by a covelent bond.

Group of atoms are known as molecules.Further atoms changes into ions either positive or negative ion when it losses or gain electrons respectively.Every atom has its own isotopes,upon the concept of isotopes it is arranged in a proper order in a periodic table.A periodic table concept was first given by Mendleev.

An atom can be further broken down in order to obtain energy.Atomic energy can also be used in atoms bombs.I t is in our choice either to use it for good purpose or bad.

 In short atom is the fundamental basis of life..