WHITE TIGER MYSTERY SOLVED BY SCIENTISTS

           The milky coats of the white Bengal tigers are caused by a single change in a know pigment gene, a new study has found. for long time the cause of this coats of the white tigers are mystery. now, scientists have discovered that their spectacular white coats are produced by a single change in a known pigment gene. " The white tiger represents part of the natural genetic diversity of the tiger that is worth conserving." said Shu-Jin Luo of the China's Peking University.

MYSTERIOUS COSMIC IMPACT CAUSES THE EXTINCTION OF THE WOOLLY MAMMOTHS??

                                           Woolly mammoths may have died as a result of the climate change following a major cosmic impact near the end of the Ice Age. A catastrophic event in Earth's history around 12,800 years ago, scorched the air, melted bedrock and altered the course of the Earth's history, researchers said. However, exactly what happened then, still unclear. Researchers say a comet may have scraped our planet's atmosphere or a meteorite may have slammed into the Earth's surface, causing global combustion. The researchers have found ample evidence to support their theory.
                                          

EARTH LIKE PLANETS IN THE ATMOSPHERES OF DEAD STARS SPOTTED

EARTH LIKE PLANETS IN THE ATMOSPHERES OF DEAD STARS SPOTTED

            The Hubble space telescope has found the signs of Earth-like planets in a very unlikely place- the atmospheres of a pair of burnt-out stars in a nearby cluster. The researchers said that, the white dwarf stars are being polluted by debris from asteroid-like objects falling on them. The stars, known as white dwarfs- small, dim remnants of stars once like the sun- reside 150 light years away in the Hyades star cluster, in the constellation of Taurus. The cluster is relatively very young, at only 625 myo. Astronomers believe that all stars formed in clusters.

                                                                                                        

                                                                                         SOURCE- THE TIMES OF INDIA

FUTURE OF THE EARTH

FUTURE OF THE EARTH

                           

                          The future of our earth is completely depends on the sun. As a result of steady accumulation of helium at the sun’s core, the sun’s total luminosity will increase slowly.  More specifically, the luminosity of the sun will grow by 10% over the next 1.1 billion years and by 40% over the next 3.6 billion years. After 4.8 billion years, when the sun becomes 67% more luminous than at present, the hydrogen fuel at the core of the sun becomes exhausted. Thereafter the sun will continue to burn hydrogen in a shell surrounding its core, until its luminosity increases 121% of its present value. This marks the end of the sun’s main sequence lifetime, and thereafter it will pass through the subgiant stage, and then evolves into a redgiant.

TILL 1.1 BILLION YEARS FROM TODAY-

                            Now with the increased surface area of the sun, the amount of energy emitted will increase. The global temperature of the earth will climb because of the rising luminosity of the sun; the rate of weathering of minerals will increase. This in turn will decrease the level of carbon-di-oxide in the atmosphere. Within the next 600 million years from the present, the concentration of carbon-di-oxide will fall below the critical threshold need to sustain photosynthesis about 50 parts per million. At that point the trees and the forest in their current form cannot survive. However, carbon fixation can continue at much lower concentration, down to above 10 parts per million. Thus plants using can be able to survive for at least .8 billion years to 1.1 billion years more. Currently   using plants represents about 5% of the Earth’s plant biomass and 1% of its known plant species. For examples 50% of all the grass species use the  photosynthetic pathway. When the levels of the carbon-di-oxide fall down to the limit where photosynthesis is barely sustainable the proportion of carbon-di-oxide in the atmosphere is expected to oscillate up and down. This will allow the land vegetation to flourish each time the level of carbon-di-oxide due to the tectonic activity and the animal life. However, the long term trend is for the plant life on land to die off altogether as most of the remaining carbon in the atmosphere becomes sequestered in the earth. Loss of these most of the land plants result the eventual loss of the oxygen. That leads to the death of animals. 1^st animals to be disappeared will be the large mammals. After that, small mammals birds, amphibians, reptiles and finally the invertebrates. Though some insects and reptiles may be survive along with the sea animals. More specifically we can say most of the multicellular lifeforms and many of the eukaryotes extinct. 1.1 billion years after today, mainly the prokaryotes exist in the planet.

AFTER 1.1 BILLION YEARS FROM TODAY-

                             After 1.1 billion years the luminosity of the sun grows by 10% of today. That makes the average temperature of the global surface to 320k. The atmosphere will become a moist greenhouse leading to a runaway evaporation of the oceans. And approximately 27% of the modern ocean will have been sub-ducted into the mantle. At this point, the model of the earth’s future demonstrates that the stratosphere would contain increasing levels of water. These water molecules will be broken down through photo-dissociation by solar ultraviolet radiation, allowing hydrogen to escape the atmosphere. We can call this time as the ocean-free era. During this ocean-free era, there will continue to be reservoirs at the surface as water is steadily released from the deep crust and mantle, where it is estimated there is an amount of water equivalent to several times that currently present in the earth’s oceans. Some water may be retained at the poles and there may be occasional rainstorms, but most part of the planet would be a dry desert with large dunefields covering its equator, resembling how Saturn’s largest moon Titan looks like today. Even in this arid condition, earth may retain some microbial, possibly even some multicellular life. Most of these microbial are halophiles. However, the increasing extreme conditions will likely leads to the extinction of the prokaryotes between 1.6 billion years to 2.8 billion years from now, with the last of them living in residual ponds of water at high latitudes and heights or in caverns with trapped ice; underground life, however, could last longer. What happened next depends on the level of tectonics activity. A steady release of the carbon-di-oxide by volcanic eruption could eventually cause the atmosphere to enter a supergreenhouse state like Venus. But without surface water, plate tectonics would probably come to a halt and most of the carbonates would remain securely buried until the sun becomes a red giant and its increased luminosity heated the rock to the point of releasing the carbon-di-oxide. The loss of the oceans could be delayed until two billion years in the future if the total atmospheric pressure were to decline. A lower atmospheric pressure would reduce the greenhouse effect, thereby lowering the surface temperature. This would occur if natural processes were to remove the nitrogen from the atmosphere. Studies of organic sediments have shown that at least 110 kilopascals i.e. .99 atm of nitrogen has been removed from the atmosphere over the past four billion years; enough to effectively double the current atmospheric pressure if it were to be released. This rate of removal would be sufficient to counter the effect of the increasing solar luminosity for the next two billion years. However, beyond that point, unless most of the earth’s surface water has been lost by the time, in which case the planet will stay in the same conditions until the starting of the red giant phase. The amount of water in the lower atmosphere will have risen to 40% and the runway moist greenhouse will commence when the luminosity from the sun reaches 35-40% more than the current value, 3-4 billion years from now. The atmosphere will heat up and the surface temperature will rise sufficiently to melt surface rock. However, most of the atmosphere will be retained until the sun has entered the red giant stage. And once the sun entered the red giant phase, the changes from burning hydrogen at its core to burning hydrogen around its shell, the core will start to contract and the outer envelope will expand. The total luminosity will steadily increase over the following billion years until it reaches 2730 times the sun’s current luminosity at the age of 12.167 billion years. During this phase the sun will experience more rapid mass loss, with about 33% of its total mass shed with the solar wind. The loss of mass will mean that the orbit of the planet will expand. The orbital distance of the earth will expand. The orbital distance of the earth will increase to at most 150% of its current value. At the final stage of the red giant phase of the sun (when the age of the sun will be 12 billion years), it is likely to expand to sallow both mercury and Venus, reaching a maximum radius of 1.2 A.U (180,000,000 km). The earth will interact tidally with the sun’s outer atmosphere, which would serve to decrease earth’s orbital radius. Drag from the chromosphere of the sun would also reduce the earth’s orbit. These effects will act to counterbalance the effect of mass loss by the sun, and the earth will most likely to be engulfed by the sun. the ablation and vaporization caused by its fall on a decaying trajectory towards the sun will remove earth’s crust and mantle, then finally destroy it after at most 200 years. Earth’s sole legacy will be a very slight increase (0.01%) of the solar metallicity. Before this happens, most of earth’s atmosphere will have been lost to space and its surface will consist of a magma ocean with floating continents of metals and metal oxides as well as icebergs of refractory materials with its surface temperature reaching more than 2,400K. The drag from the solar atmosphere may cause the orbit of the moon decay. Once the orbit of the moon closes to a distance of 18,470 km, it will cross the earth’s Roche’s limit. Tidal interaction with the earth would then break apart the moon, turning into a ring system. Most of the orbiting ring will then begin to decay, and the debris will impact the earth. Hence, even if the earth is not swallowed up by the sun, the planet may be left moonless and lifeless.

The Life Of The Polar Bear Cubs

THE LIFE OF THE POLAR BEAR CUBS

                                                  Polar bear baby cubs usually born in December or in early January in their den. Usually they born in pairs; though it is seen that there are three cubs or one cub, but it is almost rare that there are four cubs. A traditional area of these dens is called Bogan Valley. These dens are find just below the Ridge of Retzuis mountain, which is in Svalbard.

                                        We know that polar bears are the one of the largest and deadliest carnivore of the bear family. But it is very funny that cubs of the polar bears are very much opposite. They are very much dependent and helpless. It is seen that male cubs are bigger than the female cubs.

INFORMATION ABOUT THOSE DENS-
                                        When the ice floes break up in the fall, ending the possibility of hunting, each of the pregnant females digs a suitable dens. Each of these dens has one or two narrow entrance tunnel which leads their main chambers. Each den has one to three chambers. These dens usually are in the snowdrifts, but they may also be made underground in permafrost[1] if it is not sufficiently cold enough yet for snow. Normally these dens are situated on the land which is a few kilometers away from the seacoasts. Those who do not have den on the land, they have their den on the sea ice.

BIRTH OF THE CUBS-
                                        Within the middle of November, the female polar bears entered their den and closed the entrance tunnel of the den. There she enters a dormant state similar to hibernation[2]. This hibernation-like state does not consist of continuous sleeping; but in this time the heart rate of the polar bear slows down from 46 to 27 beats per minute. the body temperature of the polar bears do not decrease in this time. In this meantime female polar bears give birth to their children.

LIFE AT THE DEN-
                                                  New-born baby cubs are of around 12 inches long and of the weight around 450-690 g. New-born cubs are born in the den with no sense. They are deaf for the first 24 hours, they are blind for the first one week. Their smelling and walking ability do not develop for several weeks. After two months they will have grown a thick and protective fur. Their teeth emerged and they have the ability to walk but not in the outside, only inside the den. This den is for protection and it also provides a means of conservation of mother's heat. Mother polar bear never left their cubs alone in this time.

LIFE OUTSIDE THE DEN(EARLY STAGE)-
                                         When the weight of the cubs are around 23-35 pound, which takes almost 90 days after birth, mother polar bear breaks open those entrance tunnel and get out of the den. Cubs also get out with the mother. Though it is too early for them to leave the den completely. The cubs and their mother used to roam near the den for almost two weeks after they came out of the den, sometimes it takes more than two weeks. In this meantime, the cubs used to be familiar with the world outside den and they also develop their walking muscle in this time. Though they are starting to wander outside the den, they remain in the den around 85% of the time during this early stage of life. In this stage of life they never sleep outside the den.

LIFE OUTSIDE THE DEN(LATER STAGE)-
                                        When the cubs walking muscles are ready enough to walk in the snow without falling, mother polar bear first take them to the sea, and introduce them to the sea. If the sea is far from the den,or the family trapped into deep ice fall or open water, sometimes mother bear carry their cubs on their backs. Till the age of 18 months the cubs need intensive cares from their mother. After they crossed their age of 18 months, though they do not need intensive cares from their mother, they cannot live their life alone. Till the age of 30 months, they used to live with their mother. after that they started their new life, without their mother. After leaving the mother polar bear sibling use to live together for sometimes and hunt and share food. After some more time they used to live alone.

DIET-

                                In the early stage of life when the cubs live inside the den they just drink mother's rich-fat milk; this milk has a taste of the cord liver and the smell of the seal and fish. The milk of the polar bear is richer than the milk of the whale and contains more protein than the milk of the seal. When the polar bear cubs are starting to go to the sea coasts with their mother, they first introduced to the solid food. In this time the cubs' diet is mother's rich milk and seal blubbers. After the age of 15-18 months the cubs are gone completely carnivore.

HUNTING-

                                      Before the age of eight months they are not able to learn hunting. After eight months when they are use to go outside with their mother, they use to learn the way of hunting. Generally they first learn to hunt seals. They develop their hunting skills by watching their mother, hunting seals. But they need a lot of time to perfectly execute this technique. 

THREATS-

                                    The only threat for an adult polar bear is the human. Human hunts polar bears for their body parts. We will discuss about this in my later posts. Though human is not the threats for the polar bear cubs, they have many other threats. Their first threat is starvation.Since they are completely dependent on their  mother, So, before their birth, if mother polar bears cannot find enough food for them, then that winter becomes the last winter of the mother and the cubs. Their next threat is being hunted by other animals.    In the beginning of the life, when they live their 85% time of life in the den, sometimes mother polar bears go outside the den for collecting food, in this time, some other carnivore take the cubs with them for their diet. And their final threat is the adult male polar bear. It is seen that male polar bears sometimes kill the cubs. Though I do not find any confirm information about this killing, but I think the males kills the cubs to be in a relation with the mother polar bears. As far the female polar bears are with their child they are not ready for breeding. So males kill the cubs to be in a relation with the female.

WORDS-

permafrost[1] = soil at or below the the freezing point of the water for two or more years

hibernation[2] = to pass the winter in a dormant state

THE EVOLUTION OF POLAR BEAR

                                              In present days, Polar bears (Ursus maritimus) are generally found in the Denmark (Greenland), Norway (Svalbard), Russia, United States (Alaska) and Canada. Previously many papers are published about the evolution of the polar bears. Many of them said that polar bears were evolved from the brown bears; the polar bears were separated from the brown bears about 150,000 years ago. There is another theory that polar bears were evolved from the grizzly bears, and they were separated from the grizzly bears about 600,000 years ago. My paper is not about those ideas; rather it is a new concept of the evolution of the polar bears.

BASIC CONCEPT OF MY THEOREM

                                                 My concept of the theorem is that the polar bear was evolved from the cave bears ((Ursus spelaeus). Cave bears lived in the earth about 5.3 million years ago to 11,000 years ago. Now they are extinct. I shall give some points to establish my concept.

HABITAT

                                        The cave bear's range stretched across Europe; from Spain and Great Britain in the west, Italy, parts of Germany, Poland, the Balkans, Romania and parts of Russia, including the Caucasus; and northern Iran. The largest numbers of cave bear remains have been found in Austria, Switzerland, southern Germany, northern Italy, northern Spain, Croatia, Hungary, and Romania. The huge number of bones found in southern, central and Eastern Europe has led some scientists to think Europe may have once had literally herds of cave bears.

                                             Therefore we conclude that, after every generation the number of cave bears were increasing in a high rate or may be in a very high rate. So clearly the next generations need more places for their habitat and diet. So they migrate- Some of them migrate to the northern sides, then at 2.58 million years ago the ice age happened and ice sheets were established in Northern Europe, Antarctica and Greenland. After this they stayed in those icy cold areas.

BODY, SKELETON & PHYSICAL CHARACTERISTICS

                                               Here I’m giving some points for establishing my theory.                                        

The average weight for males(cave bears) was 400-500 kilograms or 880-1102 pounds, and for females (cave bears) was 225-250 kilograms or 496-551 pounds where the weight for males(polar bears) is 350-500 kilograms or 700-1500 pounds, and for females (polar bears) is 150-250 kilograms or 330-550 pounds. The most important point to be noted that, in the cases of both bears we can see the weight ratio of the males and females is 2:1.

If we compare the skeletons of the cave bears and polar bears, then we can find that skeletons are very similar.

The cave bears had a very broad domed skull with a steep forehead. Now if we study the skulls of the polar bears we can see they also have a very broad domed skull with a steep forehead.

      

ADOPTATION OF POLAR BEARS

                                        We know that polar bears have a great adaptation history.  Here are they-

SMALL AND ROUNDED EARS- Polar bears have small and rounded ears which help them to prevent the cold water from entering the bear’s ears and freezing their eardrums. This also helps conserve body warmth in sub-zero temperature.

LONG STIFF HAIR BETWEEN PADS OF THE BEAR’S FEET- It protects their feet from the cold and provides traction on the ice. It helps them to swim in the cold icy water and also helps them from slipping on the slippery ice. Their hair usually shakes free any water on ice formed after swimming.

HOLLOW FUR- It traps air inside, thus making the bear buoyant in water. The layer of air provides insulation between their warm bodies and the cold Arctic air & water. Insulation provided is lost when fur is covered with oil.

THICK LAYER OF FAT (BLUBBER) UNDER SKIN- It is up to 11 cm thick. It insulates bear from Arctic cold. Though it make some problems also. It causes the overheating. To prevent in warm days or after some physical works. If they are over heated, they release the heat from the body through areas where fur is absent or where blood vessels are close to the skin. Examples- muzzle, nose, ear, foot, pads, inner thighs, shoulders.

SKIN UNDER THE FUR IS BLACK- This is to ensure that the polar bear has a better heat retention rate.

                                        So we arrived to the vital question, that how this huge evolution happened within a very short time of period (respect to the evolution history).

                                        Here it’s my theory about that evolution- The population of the cave bears getting larger and larger, now from the theory of Charles Darwin we conclude that, over population creates the insufficiency of food and habitat: resulting in struggle for existence. So the relatively weak group/groups of cave bears have to migrate to other places for food and habitat. In this migration, one or more than one group migrate to the northern side of the Europe, the Antarctica and Greenland. They started their journey of life there. Then about 2.58 million years ago the ice age happened, and the whole Antarctica, Greenland and the northern Europe completely covered with ice. Permanently great ice sheet established there. Clearly that was not a favourable condition for living.  Now, as the time passed, their population getting higher again and they faced the problem of insufficient food and habitat. The climate is already against them. So these occurs,

Over population + natural destruction à struggle for existence

Struggle for existence+ confinementà  balance of nature

Balance of nature + change in conditionà struggle for existence

Struggle for existence+ beneficial variationà natural selection

Natural selection+ time à speciation

Explanation:

                                   As the time passed the population of those group of cave bears were getting larger and larger, and in the other hand ice covered the whole lands. Clearly the nature was against them. So, over population and natural destruction causes struggle for existence.

                                 This struggle for existence and their confinement in the in Northern Europe, Antarctica and Greenland causes a balance of nature. As the ice sheets completely disjoint the Northern Europe, Antarctica and Greenland from the world, so a completely new and separated eco-system created there and this was balanced.

                                 In this new eco-system some changes happened in the physical condition of the cave bears. These changes in physical conditions and natural conditions of cave bears cause changes in the organic conditions of the cave bears. So after some generation there exist cave bears whose physical and organic conditions are not the same. So in the new eco-system there exist cave bears with different variations. In the way of life it causes another struggle for existence.

                                  This struggle for existence was about the existence of the better mutating cave bears. So in this fight of existence the beneficial variation wins. That is, those cave bears whose variation were favourable in those conditions were selected by the nature

                                  The chosen variation of the nature only survives there and others were extinct. Thus as the time goes that chosen variation created a new species. The species called polar bear.

DIET –

                                   The morphological features of the cave bear chewing apparatus, including loss of premolars, have long been suggested to indicate their diets displayed a higher degree of herbivore than the Eurasian brown bear. Indeed a solely vegetarian diet has been inferred on the basis of tooth morphology. Results obtained on the stable isotopes of cave bear bones also point to a largely vegetarian diet in having low levels of nitrogen-15 and carbon-13, which are accumulated at a faster rate by carnivores as opposed to herbivores. However, some evidence points toward the occasional inclusion of animal protein in cave bear diets. For example, toothmarks on cave bear remains in areas where cave bears are the only recorded potential carnivores suggests occasional cannibalistic scavenging. So we conclude that the cave bears were omnivorous, or at least they were not completely vegetarian. Therefore when it is necessary, they can be carnivore.

                               Now we all know, polar bears are completely carnivorous.

       Now here is my concept about the evolution of cave bears into polar bears-

                                      After the glacial period, they total northern Europe, Greenland and Antarctica completely covered with ice sheet. So the temperature went too low, and all the plants died. So the only thing for diet remains, were animal proteins. Since cave bears were omnivorous, they had no problem for taking animal protein for diet.

WHY POLAR BEARS ARE NOT EVALUATED FROM GRIZZLY OR BROWN BEARS-

                                       According to my theory, polar bears came to earth about 1.5 to 1 million years ago. And they came from the cave bears. Whereas grizzly bears are very junior to them. The brown bears came to the earth almost at the same time of the time of the polar bears. Now we know at the ice age period the arctic sea was completely frozen. Now I believe, at that time some troops of the brown bears migrate there, and they entered the territory of the polar bears. There those two different types of bears met to each other. And after breeding they started a new species, its grizzly bears.

                                      Now from the concept of heredity of Mendel, we know that the characteristic of the paternal and maternal genes take part in the time of breeding. Now grizzly bear were the half-breed of the polar bear and brown bear. Hence in the DNA of grizzly bear some characteristic of brown bear and some characteristic of polar bear dominant there.

                                      Scientists find that the mitochondrial DNA of polar bear is very much similar to the mitochondrial DNA of grizzly bear, so they consider the fact that polar bears evolved from grizzly bear. Though I believe, grizzly bears are evolved from the polar bears.

                             Hence polar bears are evolved from the cave bears.