SRVVL OF THE SICKEST-MOALEM

/////////////////BAN=Synopsis

Was diabetes evolution's response to the last Ice Age? Did a deadly genetic disease help our ancestors survive the bubonic plagues of Europe? Will a visit to the tanning salon help lower your cholesterol? Why do we age? Why are some people immune to HIV? Can your genes be turned on -- or off?

Joining the ranks of modern myth busters, Dr. Sharon Moalem turns our current understanding of illness on its head and challenges us to fundamentally change the way we think about our bodies, our health, and our relationship to just about every other living thing on earth, from plants and animals to insects and bacteria.

Through a fresh and engaging examination of our evolutionary history, Dr. Moalem reveals how many of the conditions that are diseases today actually gave our ancestors a leg up in the survival sweepstakes. When the option is a long life with a disease or a short one without it, evolution opts for disease almost every time.

Everything from the climate our ancestors lived in to the crops they planted and ate to their beverage of choice can be seen in our genetic inheritance. But Survival of the Sickest doesn't stop there. It goes on to demonstrate just how little modern medicine really understands about human health, and offers a new way of thinking that can help all of us live longer, healthier lives.

Survival of the Sickest is filled with fascinating insights and cutting-edge research, presented in a way that is both accessible and utterly absorbing. This is a book about the interconnectedness of all life on earth -- and, especially, what that means for us.


////////////////MSSNG NOW MRDRD CRSS-TIMONTINI


////////////////HUMAN BRAINS DEVELOP OUTSIDE THE BIRTH CANAL


////////////////ONLY HUMANS NEED HELP WITH CHILDBIRTH -NO OTHER SPECIES NEEDS IT


//////////////Dan Ariely on Survival of the Sickest
MIT professor Dan Ariely has become one of the leaders in the growing field of behavioral economics, and his bestselling book debut, Predictably Irrational, has brought his ideas--and his ingenious experiments and charming sense of humor--to a much wider audience. With the simplest of tests (often an auction or a quiz given under a few conditions) he shows again and again not only that we are wired to make irrational decisions in many situations, but that we do so in remarkably predictable ways.

I have always been puzzled by the way in which genetic diseases have managed to survive throughout the ages. How could it be that these diseases were able to withstand the evolutionary process, where only the most fit survive, and continue to be transferred from one generation to the next? Survival of the Sickest provides a thought provoking yet entertaining explanation to this puzzle.

In this insightful book Dr. Sharon Moalem demonstrates how conditions that are considered unhealthy (such as hemochromatosis, diabetes, and high cholesterol), or even deadly in extreme cases, might actually put their carriers at an advantage in combating other life-threatening illnesses. For example, he explains that hemochromatosis, a disease that, if left untreated, will kill you, may have actually been a defense against the deadliest pandemic in history--the bubonic plague during the 14th century. It turns out that this genetic mutation, which continues to be passed down through generations, actually helped spare many lives at one point.

Throughout the book, Dr. Moalem draws many connections between seemingly disparate subjects, such as the accidental invention of ice wine and cold diuresis, in order to illustrate the basic mechanisms of genetics and medicine in charming and intuitive ways. He skillfully interweaves his knowledge of history, genetics, and medicine not only as they relate to specific medical conditions but also in a way that addresses important challenges of modern society and our future evolution.

In the most general terms, Dr. Moalem's description of the human body and its complexity left me in awe of how far we have come in our understanding of biology and medicine, while also being reminded that the road to understanding ourselves is still wide open with much more to learn in the decades, and even centuries, to come. It is a fantastic journey on which he leads us and Dr. Moalem is a kind, knowledgeable, humorous, and helpful guide.



///////////////PLIOCINE-2 TO 5MYA-HUMANS ENTERED PLIOCENE AS HAIRY QUADRUPEDS AND EXITED PLIOCENE AS HAIRLESS BIPEDS


///////////////Moalem, a medical student with a Ph.D. in neurogenetics, asks a number of provocative questions, such as why debilitating hereditary diseases persist in humans and why we suffer from the consequences of aging. His approach to these questions is solidly rooted in evolutionary theory, and he capably demonstrates that each disease confers a selective advantage to individuals who carry either one or two alleles for inherited diseases. But very little is new; the principles, if not every particular, that Moalem addresses have been covered in Randolph Nesse and George Williams's Why We Get Sick, among others. Whether he is discussing hemochromatosis (a disorder that causes massive amounts of iron to accumulate in individuals), diabetes or sickle cell anemia, his conclusion is always the same: each condition offers enough positive evolutionary advantages to offset the negative consequences, and this message is repeated over and over. .....RB=


////////////////This book about genetics, evolution and disease is a genuine page turner, that's how deeply interesting it is, and how well it is written. The basic premise runs like this: The environment puts pressure on all living things, including humans, to evolve characteristics that help us survive long enough to reproduce and pass on our genes. Over the millenia, various conditions such as drought, ice ages and other climate changes have sparked genetic mutations that enhance our abilities to survive. These include some biological conditions that are advantageous in the short term, but sometimes detrimental in the long term.

For example, today we consider diabetes mellitus a serious disease because it raises human blood sugars to dangerous levels that can result in loss of limbs and sight, among other problems. However, in an ice age, when temperatures were significantly lower than they are now, having extra sugar in the blood may have enabled our ancestors to survive the cold because sugar lowers the temperature at which we freeze to death. Similarly, Sickle Cell Anemia may have evolved to help people resist malaria.

What's especially interesting is that this theory would explain why ethnic groups that are prone to diabetes -- Scandinavians and people from the British Isles, for instance -- originally came from northern areas that were at one time covered by glaciers. And the ancestors of those groups that tend to carry the genes for Sickle Cell generally originated from climates in which malaria was prevalent.

Another intriguing idea is that some "sicknesses" only become serious problems when an individual is older and past his or her prime reproductive years. So if one of our ancestors had, for instance, a chronic disease like diabetes, it probably wouldn't kill him/her until after the person had children.

There are many such fascinating observations and facts in this relatively short book and I highly recommend it to anyone who wonders how things and people got to be the way they, and we, are today.


//////////SAVANNA HYPOTHESIS OF BIPEDALISM


/////////////////WH=We're used to thinking of disease as the enemy, as a malicious force that makes our lives shorter and more miserable. That may be exactly what "disease" is on an individual basis--but its value to the species as a whole is a different matter.

Dr. Moalem elegantly explains why medical conditions that are deemed to be diseases today often helped our ancestors survive and reproduce in difficult environments. Take hemochromatosis, a hereditary condition that causes iron to accumulate in a person's internal organs, eventually leading to death. Although the gene that causes hemochromatosis was once thought to be rare, research completed in 1996 found that it's actually surprisingly common. Why wouldn't such a terrible disease have been "bred out" of our species long ago? The answer is that hemochromatosis reduces the amount of iron available to iron-loving bacteria, such as the bubonic plague that depopulated Europe in the mid-1300s. A person living in the Middle Ages with the hemochromatosis gene would have eventually died from iron build up, but in the meantime would have have had a smaller chance of dying from the plague and other iron-loving infections--in an age when few people lived past the age of 50, the disease resistance conferred by hemochromatosis far outweighed the disadvantage that would have materialized if the person carrying the gene had lived to old age. People with hemochromatosis reproduced and passed the gene one to their heirs; those without it died of the plague, without children.

"Survival of the Sickest" is filled with similarly surprising observations. Anemia may be the body's way of reducing iron available to bacteria--giving an iron supplement to a malnourished population may be a bad idea and ironically (so to speak) medical bloodletting may not have been such a bad idea. Type II diabetes may have been a condition that conferred an advantage on northern Eurpoeans during the ice age, when an increase in sugar in the bloodstream and frequent urination would have reduced the risk of freezing to death. Similarly, sickle cell anemia offers protection from malaria. In the "good old days," a genetic condition that kept a person from dying before reproducing would have been a boon, even if the condition would have turned killer if the person managed to reach old age.

The book is filled with other "big ideas, briefly discussed." Instead of battling bacteria with antibiotics (which is only making them tougher), perhaps we could manage their evolution so that they thrive by inconveniencing their host (like a cold) instead of by flooring it (like malaria). And, although Dr. Moalem seems to agree that natural selection is the big driver of evolution, he observes that perhaps Lamarck wasn't so far off after all--jumping genes, retroviruses and methylation all suggest that an organism's life experiences can in certain circumstances affect future generations. As for aging--perhaps our bodies are designed by natural selection to limit the number of times a cell can reproduce (thus insuring that we will all die from old age if something else doesn't get us first), the alternative being an excess of cells without such a limit (in other words, cancer).

On the whole, "Survival of the Sickest" is readable, surprising and filled with "ah-ha!" moments. If you enjoyed "The Tipping Point" or "Freakonomics," you'll probably be intrigued by Dr. Maolem's often counter-intuitive observations.


//////////////////Aquatic ape hypothesis · Evolution
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The aquatic ape hypothesis (AAH), sometimes referred to as the aquatic ape theory, asserts that wading, swimming and diving for food exerted a strong evolutionary effect on the ancestors of the genus Homo and is in part responsible for the split between the common ancestors of humans and other great apes. The AAH attempts to explain the large number of physical differences between humans and other apes, such as lack of body hair, larger brains and upright posture, in terms of the methods of feeding and types of food of early hominids living in coastal and river regions.



////////////////AQUATIC APE MADE US BIPEDAL AND FURLESS?



////////////////SAVANNA VERSUS SEMIAQUATIC APE HYPOTHESIS



//////////////////////Savannah hypothesis

This proposes that the onset of drier conditions severely reduced the amount of wooded habitats. During this period, when the forests became thin, early hominids adapted to an environment which was now more like the liminal forest-savanna mosaic zones of equatorial Africa. In order to remain effective in gathering food, the hominids had to travel relatively long distances with food or tools, thus making quadrupedalism extremely inefficient. Bipedalism developed both as an adaptation to facilitate movement across the grasslands and as a way to give early hominids use of their hands for food cultivation and tool use since they were no longer needed for locomotion.


//////////////AQUATIC APE -WATERBIRTH EASIER?


///////////////.......Other features of plants and animals, such as the wings of ostriches, may once have been adaptations but are no longer needed for their original purpose. Such "vestigial traits" can persist because they are neutral, because they have taken on another function or because there hasn't been enough evolution to eliminate them even though they have become disadvantageous. Take the appendix. There are plenty of claims that it has this or that function but the evidence is clear: you are more likely to survive without an appendix than with one.

So why hasn't it disappeared? Because evolution is a numbers game. The worldwide human population was tiny until a few thousand years ago, and people have few children with long periods between each generation. That means fewer chances for evolution to throw up mutations that would reduce the size of the appendix or eliminate it altogether – and fewer chances for those mutations to spread through populations by natural selection. Another possibility is that we are stuck in an evolutionary Catch-22 where, as the appendix shrinks, appendicitis becomes more likely, favouring its retention.

Wisdom teeth are another vestigial remnant. A smaller, weaker jaw allowed our ancestors to grow larger brains, but left less room for molars. Yet many of us still grow teeth for which there is no room, with potentially fatal consequences. One possible reason why wisdom teeth persist is that they usually appear after people reach reproductive age, meaning selection against them is weak.


///////////////LWTL=LOSING WILL TO LV


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