Poles Apart

1. Polar Opposites: The Arctic region is essentially a frozen ocean surrounded by land. Conversely, Antarctica is a continent-with mountain ranges and lakes-surrounded by an ocean. Socially and politically, though, the Arctic region includes the northern territories of Canada, Greenland (a territory of Denmark), Russia, Iceland, Norway, Sweden, Finland and the United States.
2. Most Ice: The southernmost continent has roughly 90 percent of the world's ice, which amounts to nearly three quarters of the Earth's fresh water being locked away there. This has led some to float the idea of towing icebergs to quench dry, drought-stricken areas. In fact, Prince Mohammed al Faisal of Saudi Arabia once considered a plan to find a 100 million-ton iceberg off Antarctica and tow it to the Arabian peninsula.
3. No-Man's Land: Despite symbolic images of past explorers triumphantly planting flags at the South Pole, the continent remains the only place on Earth not owned by anyone. It has no history of native peoples and is governed by the Antarctic treaty, which maintains that the land and resources be used for peaceful and scientific purposes. This is in stark contrast to the more than 4 million people living within the Arctic circle in several small towns as well as major cities such as Barrow, Alaska; Tromso, Norway; and Muramansk and Salekhaard in Russia.
4. Black Gold: Energy-hungry nations are forging northward as an estimated one quarter of all untapped oil reserves lie north of the Arctic circle, according to the U.S. Geological Survey. Russia has taken the bold step of laying claim to a large swath of the Arctic region in hopes of exploring gas deposits in the Lomonosov Ridge-a 1,200-mile underwater mountain range purported to hold up to 10 billion tons of the coveted resource. Even the U.S. is getting involved, sending an icebreaker ship to map out their Arctic territory off Alaska. While it is believed by some that deposits of petroleum exist in the southern continental shelf, such as the area under the Ross Sea, the Antarctic Treaty makes oil drilling momentarily off-limits.
5. Penguins and Polar Bears: Christmas cards and Coke commercials can be blamed for the misconception that polar bears and penguins live in the same frigid neighborhood. If penguins of the Antarctic and Artic-dwelling polar bears ever did cross the same frozen paths, the waddling birds would make for very easy prey for the giant bears. But since penguins needn't worry about land predators, they have adapted their wings into paddle-like flippers to maneuver through the ocean.
6. Santa Claus' Address: Every Christmas, thousands of letters mailed to Santa Claus do make it to the North Pole... North Pole, Alaska that is. The small town of roughly 1,778 people advertises its ZIP code as the ZIP code of Santa. The Holiday spirit is felt year-round as candy-cane striped street lights keep things moving along festive places such as St. Nicholas Drive, Snowman Lane and Kris Kringle Drive.
7. Battle of the Brrr: The Antarctic is so cold that the snow never melts in many areas of the continent. The region's average temperature is about -56 degrees Fahrenheit (-49 degrees Celsius), making it the coldest climate on earth. In contrast, the Arctic's average winter temperature is -29 degrees Fahrenheit (-34 degrees Celsius), but it gets warmer in the summer. The lowest temperature ever recorded on Earth was -128 degrees Fahrenheit (-89.6 degrees Celsius), recorded July 21, 1983, at the Vostok Station located near the South Geomagnetic Pole.
8. The Ozone Hole: While the Antarctic has an ozone hole that has grown to about three times the size of the United States' land mass, the Arctic is losing ozone coverage as well. In truth, there is no actual hole; the "hole" is a region of severely depleted ozone, a chemical that helps protect the planet from harmful solar radiation. Ozone losses in the Northern Hemisphere are lower than in the Southern because warmer Arctic temperatures limit the formation of polar stratospheric clouds that destroy ozone. But temperatures in the stratosphere, high above the Arctic, have gradually cooled over the last decade, resulting in increased ozone loss.
9. Cracks in the Ice: Being primarily a thin layer of ice, the arctic is very sensitive to changing climate conditions. Warmer temperatures during the summer months cause the 12 to 15 feet thick ice sheet to melt and break apart. Last year, researchers reported for the first time that cracks in the ice had reached all the way to the North Pole.
10. Meltdown: The Arctic has a normal melting cycle in which about half of the ice pack disappears in the summer, only to grow back to the size of the United States during the winter. Still, an alarming recent study determined that the 2-mile-thick ice sheet in Greenland is melting so rapidly that half of it could be gone by the end of the century. Other studies have found that the entire Arctic could be ice-free during summer in a few decades. Lately, research has also found that the Antarctic is also losing ice, which if all melted (no one expects this to happen anytime soon), would cause sea levels to rise roughly 200 feet.

For the original article, visit:

http://www.livescience.com/environment/top10_polar_differences-1.html

What Drives Evolution?

During the last 31 years of my geoscience association - five years of geoscience education during 1976-81 and the rest as a professional petroleum geologist - I distinctingly remember asking all Palaeontologists, I have met, this simple question “What drives evolution?” Or to put it in a different format “Why evolution goes only in a forward direction (parellel to time-axis) i.e. from simple to complex forms, not in the reverse direction?”. I still brood over this question and was very happy to see two articles published in www.livescience.com. The article by Jeanna Bryner with some editing is reproduced below.

From bizarre butterfly spots to rainbow-colored lizards to adaptations that allow squirrels and even snakes to "fly," physical innovations in the natural world can be mind-boggling. Natural selection is accepted by scientists as the main engine driving the array of organisms and their complex features. But is evolution via natural selection the only explanation for complex organisms? "I think one of the greatest mysteries in biology at the moment is whether natural selection is the only process capable of generating organismal complexity," said Massimo Pigliucci of the Department of Ecology and Evolution at Stony Brook University in New York, "or whether there are other properties of matter that also come into play. I suspect the latter will turn out to be true."

Forces of Evolution:
The developing research area on how the vast biodiversity on Earth evolves accepts natural selection and three other established forces of evolution as its basis. These include: mutation, random genetic drift and gene flow.

• Natural selection is the process by which the best-adapted individuals produce the most offspring, which in turn carry forward to their offspring the genes that gave their parents the upper edge.
• Genetic drift is a random process in which chance plays a role in deciding which gene variants (alleles) survive.
• Gene flow occurs when genes are carried from one population to another. Also called migration, an example of gene is when pollen gets blown to a region where it previously did not exist, transporting new genetic material to that population.
• Mutations are also random. Changes to an organism's DNA can impact all aspects of its life, from how it looks and behaves to its basic physiology.

Flexible Genes:
Some scientists are proposing additions to the above list of evolutionary forces.
"Over the past decade or two, scientists have begun to suspect that there are other properties of complex systems (such as living organisms) that may help, together with natural selection, explain how things such as eyes, bacterial flagella, wings and turtle shells evolve," Pigliucci told LiveScience.

One idea is that organisms are equipped with the flexibility to change their physical or other features during development to accommodate environmental changes, a phenomenon called phenotypic plasticity. The change typically doesn't show up in the genes. For instance, in social bees, both the workers and guards have the same genomes but different genes get activated to give them distinct behaviors and appearances. Environmental factors, such as temperature and embryonic diet, prompt genetic activity that ends up casting one bee a worker and the other a guard. If beneficial, this flexibility could be passed on to offspring and so can lead to the evolution of new features in a species. "This plasticity is heritable, and natural selection can favor different kinds of plasticity, depending on the range of environmental conditions the organism encounters," Pigliucci said.

Made to Order:
Self-organization is another evolutionary force that some experts say whips up complex features or behaviors spontaneously in living and non-living matter, and these traits are passed on to offspring through the generations. "A classic example outside of biology are hurricanes: These are not random air movements at all, but highly organized atmospheric structures that arise spontaneously given the appropriate environmental conditions," Pigliucci said. "There is increasing evidence that living organisms generate some of their complexity during development in an analogous manner."

A biological illustration of self-organization is protein-folding. A lengthy necklace of amino acids bends, twists and folds into a three-dimensional protein, whose shape determines the protein's function. A protein made up of just 100 amino acids could take on an endless number (billions upon billions) of shapes. While this shape-shifting takes on the order of seconds to minutes in nature, the fastest computers don't have the muscle yet to pull off the feat. The mechanism that triggers the final form could be a chemical signal, for instance.

Novelties in Nature:
The environment also could drive changes in an animal's appearance or phenotype, a phenomenon that intrigues many biologists. For instance, Sean Carroll, a molecular biologist at the University of Wisconsin-Madison, discovered butterflies in East Africa have different colorings depending on when they hatch. Those hatching during the wet season emerge with brightly colored eyespots while their dry-season relatives wear neutral cryptic coats.

Biology has a pretty good understanding of how animals develop from a fertilized egg to a fully formed organism. "We just don't understand how ... the environment and [the] genetic blueprint interact during development," said Theunis Piersma of the Center for Ecological and Evolutionary Studies at the University of Groningen in the Netherlands. Piersma's research on shorebirds called red knots has revealed the birds can morph their phenotypes depending on their migration routes. When brought into captivity and placed in colder temperature environments, the shorebirds' flight muscles and organs shrink to reduce heat loss. The birds pass on to offspring the capacity to make these changes.

So the mystery is starting to clear around how diverse species with an array of features evolve. The field, which had relied in the past mostly on fossil records, got a boost with the development of genetic techniques and the integration of diverse sectors of science, connecting genetics, biology, ecology and computer science.

While scientists are shedding light on natural mechanisms that work to shape species, many questions in the field are brewing on the lab-bench. And the original question examined by Charles Darwin - what is the mechanism that causes new species to evolve - has yet to be fully explained. And another related question looms: How important are chance events, as opposed to natural selection, to shaping organisms?

For the original article, click the link below:

http://www.livescience.com/strangenews/070816_gm_evolution.html

The Sixth Extinction

The article The Sixth Extinction by the renowned Paleontologist Dr. Niles Eldredge is reproduced below with partial modifications.

There is little doubt left in the minds of professional biologists that Earth is currently faced with a mounting loss of species that threatens to rival the five great mass extinctions of the geological past. As long ago as 1993, Harvard biologist E.O. Wilson estimated that Earth is currently losing something of the order of 30,000 species per year -- which breaks down to the even more daunting statistics of some three species per hour. Some biologists have begun to feel that this biodiversity crisis --"Sixth Extinction" - is even more severe, and more imminent, than Wilson had supposed.

Extinction in the past
Our planet has been shaken by five major extinctions in the 3.5 billion year history of life. The past extinctions were all caused by abnormal physical events way outside the normal climatic and other physical disturbances which species, and entire ecosystems, normally experience and survive.

First major extinction (440 Ma): Climate change (relatively severe and sudden global cooling) seems to have been at work at the end-Ordovician mass extinction that caused such pronounced change in marine life (little or no life existed on land at that time). This occurred shortly after the evolution of the first land-based plants and 100 million years after the Cambrian Explosion of animal life beneath the seas. 25% of families lost (a family may consist of a few to thousands of species).

Second major extinction (370 Ma): The next such event, near the end of the Devonian, may or may not have been the result of global climate change. 19% of families lost.

Third major Extinction (245 Ma): Scenarios explaining what happened at the greatest mass extinction event of them all (so far, at least!) at the end of the Permian have been complex amalgams of climate change perhaps rooted in plate tectonics movements. Very recently, however, evidence suggests that an asteroid impact similar to the end-Cretaceous event may have been the cause. 54% of families lost.

Fourth major extinction (210 Ma): The event at the end of the Triassic, shortly after dinosaurs and mammals had first evolved, also remains difficult to pin down in terms of precise causes. 23% of families lost.

Fifth major extinction (65 Ma): Most famous, perhaps, was the most recent of these events at the end-Cretaceous. It wiped out the remaining terrestrial dinosaurs and marine ammonites and ended the reptilian dominance of the Earth leading to the current mammalian domination of the Earth. Consensus has emerged in the past decade that this event was caused by one (possibly multiple) collisions between Earth and extraterrestrial bodies. Some geologists, however, point to the great volcanic event that produced the Deccan Traps of India as part of the chain of physical events that disrupted ecosystems so severely that many species on land and sea rapidly succumbed to extinction. 17% of families lost.

How is the Sixth Extinction different from previous events?
Every year, between 17,000 and 100,000 species vanish from our planet says the famous Paleoanthropologist, Dr. Richard Leakey. At first glance, the physically caused extinction events of the past might seem to have little or nothing to tell us about the current Sixth Extinction, which is a patently human-caused event. For there is little doubt that humans are the direct cause of ecosystem stress and species destruction in the modern world through such activities as (1) transformation of the landscape, (2) overexploitation of species, (3) pollution, and (4) the introduction of alien species. And because Homo sapiens is clearly a species of animal (however behaviorally and ecologically peculiar an animal), the Sixth Extinction would seem to be the first recorded global extinction event that has a biotic, rather than a physical cause. Yet, upon further reflection, human impact on the planet is a direct analogue of the Cretaceous meteorite collision. Sixty-five million years ago that extraterrestrial impact -- through its sheer explosive power, followed immediately by its injections of so much debris into the upper reaches of the atmosphere that global temperatures plummeted and, most critically, photosynthesis was severely inhibited -- wreaked havoc on the living systems of Earth. That is precisely what human beings are doing to the planet right now: humans are causing vast physical changes on the planet.

What is the Sixth Extinction?
We can divide the Sixth Extinction into two discrete phases: Phase One began when the first modern humans began to disperse to different parts of the world about 100,000 years ago. Phase Two began about 10,000 years ago when humans turned to agriculture.

The first phase began shortly after Homo sapiens evolved in Africa and the anatomically modern humans began migrating out of Africa and spreading throughout the world. Humans reached the Middle East 90,000 years ago. They were in Europe starting around 40,000 years ago. Neanderthals, who had long lived in Europe, survived our arrival for less than 10,000 years, but then abruptly disappeared -- victims, according to many Paleoanthropologists, of our arrival through outright warfare. Everywhere, shortly after modern humans arrived, many (especially, though by no means exclusively, the larger) native species typically became extinct. Humans were like bulls in a China shop:

• They disrupted ecosystems by over-hunting species, which never experienced contact with humans before.
• And perhaps they spread microbial disease-causing organisms as well.

The fossil record attests to human destruction of ecosystems:

• Humans arrived in large numbers in North America roughly 12,500 years ago-and sites revealing the butchering of mammoths, mastodons and extinct buffalo are well documented throughout the continent. The demise of the bulk of the La Brea tar pit Pleistocene fauna coincided with our arrival.
• The Caribbean lost several of its larger species when humans arrived some 8000 years ago.
• Extinction struck elements of the Australian megafauna much earlier-when humans arrived some 40,000 years ago. Madagascar-something of an anomaly, as humans only arrived there two thousand years ago-also fits the pattern well: the larger species (elephant birds, a species of hippo, plus larger lemurs) rapidly disappeared soon after humans arrived.

Only in places where earlier hominid species had lived (Africa, of course, but also most of Europe and Asia) the fauna, already adapted to hominid presence, survived the first wave of the Sixth Extinction. The rest of the world's species, which had never before encountered hominids in their local ecosystems, were in direct competition for survival with the new arrivals.

Why does the Sixth Extinction continue?
Phase two of the Sixth Extinction began around 10,000 years ago with the invention of agriculture. Agriculture represents the single most profound ecological change in the entire 3.5 billion-year history of life. With its invention:

• humans did not have to interact with other species for survival, and so could manipulate other species for their own use
• humans did not have to adhere to the ecosystem's carrying capacity, and so could overpopulate

Homo sapiens became the first species to stop living inside local ecosystems. All other species, including our ancestral hominid ancestors, all pre-agricultural humans, and remnant hunter-gatherer societies still extant exist as semi-isolated populations playing specific roles in local ecosystems. This is not so with post-agricultural revolution humans, who in effect have stepped outside local ecosystems. Indeed, to develop agriculture is essentially to declare war on ecosystems - converting land to produce one or two food crops, with all other native plant species all now classified as unwanted "weeds" -- and all but a few domesticated species of animals now considered as pests.

• Estimates vary, but range between 1 and 10 million people on earth 10,000 years ago.
• There are now over 6 billion people.
• The numbers continue to increase logarithmically -- so that there will be 8 billion by 2020. There is presumably an upper limit to the carrying capacity of humans on earth -- of the numbers that agriculture can support -- and that number is usually estimated at between 13-15 billion, though some people think the ultimate numbers might be much higher.

This explosion of human population, especially in the post-Industrial Revolution years of the past two centuries, coupled with the unequal distribution and consumption of wealth on the planet, is the underlying cause of the Sixth Extinction. There is a vicious cycle. More lands are cleared and more efficient production techniques (most recently engendered largely through genetic engineering) to feed the growing number of humans -- and in response, the human population continues to expand. Higher fossil energy use is helping agriculture spread, further modifying the environment. Can conservation measures stop the Sixth Extinction? The world's ecosystems have been plunged into chaos, with some conservation biologists thinking that no system, not even the vast oceans, remains untouched by human presence. Conservation measures, sustainable development, and, ultimately, stabilization of human population numbers and consumption patterns seem to offer some hope that the Sixth Extinction will not develop to the extent of the third global extinction at 245 Ma, when 90% of the world's species were lost. Though it is true that life, so incredibly resilient, has always recovered (though after long lags) after major extinction spasms, it is only after whatever has caused the extinction event has dissipated. That cause, in the case of the Sixth Extinction, is ourselves -- Homo sapiens. This means we can continue on the path to our own extinction, or, preferably, we modify our behavior toward the global ecosystem of which we are still very much a part. The latter must happen before the Sixth Extinction can be declared over, and life can once again rebound.

Click http://www.actionbioscience.org/for the original article.

What is Time?

Unlike Matter, Energy and Space, Time is not an independent entity. It is merely a concept that emerges out of the status of evolution of any system including the universe as a whole. If there are no changes in the state of a system in any form whatsoever, the concept of Time is bound to lose its meaning altogether.

In nature, we find systems evolving spontaneously and we characterize their evolution by an abstract parameter called Time. Keeping pace with such self-induced evolutionary manifestations, this parameter runs without stop, while the concept of “present” remains eternally frozen. The measure of Time is nothing but the coordinate of this ever-running “present”. Every instant that elapses, the present moves a bit ahead, engulfs the future and merges with the past. And in course of such evolution, every system passes through a definite sequence of states. The connecting thread, being apparently ensured by causal relations, leads to the apparent flow of Time in a particular direction, namely from the past to the future.