The MIT Biology Department core courses, 7.012, 7.013, and 7.014, all cover the same core material, which includes the fundamental principles of biochemistry, genetics, molecular biology, and cell biology. Biological function at the molecular level is particularly emphasized and covers the structure and regulation of genes, as well as, the structure and synthesis of proteins, how these molecules are integrated into cells, and how these cells are integrated into multicellular systems and organisms. In addition, each version of the subject has its own distinctive material. http://ocw.mit.edu .
Of all the things MA has not understood Sex is one thing he has understood the least.
People earn for it ,yet they do not know why.
New Study on Why we have Sex is quite revealing or even shocking.
Read On.
“Sex is hard to explain,” writes Michael Brothurst in a recent article in the journal Science. Like others in his field, Brothurst, who studies the evolution of sexual reproduction at the University of Liverpool, doesn’t “get” men….
The most likely explanation is known as the Red Queen hypothesis, named after the monarch in Lewis Carroll‘s “Through the Looking Glass.” In that novella, Alice and the Red Queen hold a race in which they run in place but never get anywhere. Somewhat analogously, the Red Queen hypothesis holds that organisms and the parasites that live on them are running a race in which they constantly evolve in response to each other’s genetic mutations , maintaining an overall balance. [Read: Sex Stats: Virgins On the Rise ]
As parasites evolve to take advantage of the weaknesses of a typical host organism, Brothurst explains, host organisms with rare versions of genes, known as alleles, are less susceptible to the parasites, and so stand a better chance of surviving to their reproductive age; likewise, their offspring are endowed with these advantageous alleles. As a result, over generations these organisms’ rare alleles become more common in the population, so parasites start evolving to take them on. At that point new unusual alleles begin to flourish among the hosts.
Sex, the theory holds, gives host organisms a leg-up on this evolutionary treadmill. “This continual selection for rarity favors sexual reproduction over asexual reproduction; sexual recombination allows hosts to reshuffle their pack of alleles and generate new, rare combinations in their offspring,” Brothurst writes.
The Gaia hypothesis has also inspired analogies and various interpretations in social sciences, politics, and religion under a vague philosophy andmovement.
…
The importance of the large number of species in an ecosystem, led to two sets of views about the role played by biodiversity in the stability of ecosystems in Gaia theory. In one school of thought labelled the “species redundancy” hypothesis, proposed by Australian ecologist Brian Walker, most species are seen as having little contribution overall in the stability, comparable to the passengers in an aeroplane who play little role in its successful flight. The hypothesis leads to the conclusion that only a few key species are necessary for a healthy ecosystem. The “rivet-popper” hypothesis put forth by Paul R. Ehrlich and his wife Anne H. Ehrlich, compares each species forming part of an ecosystem as a rivet on the aeroplane (represented by the ecosystem). The progressive loss of species mirrors the progressive loss of rivets from the plane, weakening it till it is no longer sustainable and crashes.[15]
Later extensions of the Daisyworld simulation which included rabbits, foxes and other species, led to a surprising finding that the larger the number of species, the greater the improving effects on the entire planet (i.e., the temperature regulation was improved). It also showed that the system was robust and stable even when perturbed. Daisyworld simulations where environmental changes were stable gradually became less diverse over time; in contrast gentle perturbations led to bursts of species richness. These findings lent support to the idea that biodiversity is valuable.[16]
This finding was later proved in a eleven-year old study of the factors species composition, dynamics and diversity in successional and native grasslands in Minnesota by David Tilman and John A. Downing wherein they discovered that “primary productivity in more diverse plant communities is more resistant to, and recovers more fully from, a major drought”. They go on to add “Our results support the diversity stability hypothesis but not the alternative hypothesis that most species are functionally redundant”.[15][17]
Under Science it can be analysed from Biology and Mathematics.
The basis for Life , as we assume is Hydrogen and Oxygen.
Based on these parameters, wherever these substances are available, the chances of Life are high.
But we do not seem to be getting ant where till date with this information for we have found places with abundance of water, still no signs of Life.
Mathematically speaking the chances of Life in the Universe are as high/low as
A Spiral Galaxy.
The mathematical model produced by Prof Andrew Watson suggests that the odds of finding new life on other Earth-like planets are low because of the time it has taken for beings such as humans to evolve and the remaining life span of the Earth. Structurally complex and intelligent life evolved late on Earth and this process might be governed by a small number of very difficult evolutionary steps.
Prof Watson, from the School of Environmental Sciences, takes this idea further by looking at the probability of each of these critical steps occurring in relation to the life span of the Earth, giving an improved mathematical model for the evolution of intelligent life.
According to Prof Watson a limit to evolution is the habitability of Earth, and any other Earth-like planets, which will end as the sun brightens. Solar models predict that the brightness of the sun is increasing, while temperature models suggest that because of this the future life span of Earth will be ‘only’ about another billion years, a short time compared to the four billion years since life first appeared on the planet.
“The Earth’s biosphere is now in its old age and this has implications for our understanding of the likelihood of complex life and intelligence arising on any given planet,” said Prof Watson.
“At present, Earth is the only example we have of a planet with life. If we learned the planet would be habitable for a set period and that we had evolved early in this period, then even with a sample of one, we’d suspect that evolution from simple to complex and intelligent life was quite likely to occur. By contrast, we now believe that we evolved late in the habitable period, and this suggests that our evolution is rather unlikely. In fact, the timing of events is consistent with it being very rare indeed.”
Prof Watson suggests the number of evolutionary steps needed to create intelligent life, in the case of humans, is four. These probably include the emergence of single-celled bacteria, complex cells, specialized cells allowing complex life forms, and intelligent life with an established language.
“Complex life is separated from the simplest life forms by several very unlikely steps and therefore will be much less common. Intelligence is one step further, so it is much less common still,” said Prof Watson.
His model, published in the journal Astrobiology, suggests an upper limit for the probability of each step occurring is 10 per cent or less, so the chances of intelligent life emerging is low – less than 0.01 per cent over four billion years.
Each step is independent of the other and can only take place after the previous steps in the sequence have occurred. They tend to be evenly spaced through Earth’s history and this is consistent with some of the major transitions identified in the evolution of life on Earth.”
By the above Logic, Life must exist in places where the Stars are old and at a time of its Evolution is comparable to the time when Life evolved in Earth.
Even here we are drawing a blank or are we not looking properly?
Again, since we know(assume?) Life on Earth has evolved from Bactria , we assume that All Life forms must follow the same procedure.
I do not think this is sound Logic.
There is a probability that Life might have evolved through some other process of which we know nothing.
The building block of Life may be different from what is found on Earth.
Taking these facts into consideration I feel that we are not alone and that now we lack the technology and skills to track it.
Related:
When speaking about the probability of extraterrestrial life, Carl Sagan, always said that extraordinary claims required extraordinary evidence. Recent discoveries of planets similar to Earth in size and proximity to the planets’ respective suns have sparked scientific and public excitement about the possibility of also finding Earth-like life on those worlds.
“Fossil evidence suggests that life began very early in Earth’s history and that has led people to determine that life might be quite common in the universe because it happened so quickly here, but the knowledge about life on Earth simply doesn’t reveal much about the actual probability of life on other planets,” says Princeton astrophysical sciences professor Edwin Turner.
But Princeton Universityresearchers have found that the expectation that life — from bacteria to sentient beings — has or will develop on other planets as on Earth might be based more on optimism than scientific evidence.Turner and David Spiegel, a former Princeton postdoctoral researcher, analyzed what is known about the likelihood of life on other planets in an effort to separate the facts from the mere expectation that life exists outside of Earth. The researchers used a Bayesian analysis — which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist — to determine the probability of extraterrestrial life once the influence of these presumptions is minimized.
Turner and Spiegel, who is now at the Institute for Advanced Study, reported in the Proceedings of the National Academy of Sciences that the idea that life has or could arise in an Earth-like environment has only a small amount of supporting evidence, most of it extrapolated from what is known about abiogenesis, or the emergence of life, on early Earth. Instead, their analysis showed that the expectations of life cropping up on exoplanets — those found outside Earth’s solar system — are largely based on the assumption that it would or will happen under the same conditions that allowed life to flourish on this planet.
In fact, the researchers conclude, the current knowledge about life on other planets suggests that it’s very possible that Earth is a cosmic aberration where life took shape unusually fast. If so, then the chances of the average terrestrial planet hosting life would be low.
“Information about that probability comes largely from the assumptions scientists have going in, and some of the most optimistic conclusions have been based almost entirely on those assumptions,” Turner said.
Turner and Spiegel used Bayes’ theorem to assign a sliding mathematical weight to the prior assumption that life exists on other planets. The “value” of that assumption was used to determine the probability of abiogenesis, in this case defined as the average number of times that life arises every billion years on an Earth-like planet. Turner and Spiegel found that as the influence of the assumption increased, the perceived likelihood of life existing also rose, even as the basic scientific data remained the same.
“If scientists start out assuming that the chances of life existing on another planet as it does on Earth are large, then their results will be presented in a way that supports that likelihood,” Turner said. “Our work is not a judgment, but an analysis of existing data that suggests the debate about the existence of life on other planets is framed largely by the prior assumptions of the participants.”
Joshua Winn, an associate professor of physics at the Massachusetts Institute of Technology, said that Turner and Spiegel cast convincing doubt on a prominent basis for expecting extraterrestrial life. Winn, who focuses his research on the properties of exoplanets, is familiar with the research but had no role in it.
“There is a commonly heard argument that life must be common or else it would not have arisen so quickly after the surface of the Earth cooled,” Winn said. “This argument seems persuasive on its face, but Spiegel and Turner have shown it doesn’t stand up to a rigorous statistical examination — with a sample of only one life-bearing planet, one cannot even get a ballpark estimate of the abundance of life in the universe.”
“I also have thought that the relatively early emergence of life on Earth gave reasons to be optimistic about the search for life elsewhere,” Winn said. “Now I’m not so sure, though I think scientists should still search for life on other planets to the extent we can.
It’s possible that the family tree of all life on Earth has its roots on Mars — and a new device could put that theory to the test in a few years, researchers say.
Researchers are developing an instrument that would search through samples of Martian dirt, isolating any genetic material from microbes that might be present — bugs that are living or that died relatively recently, within the last million years or so. Scientists could then use standard biochemical techniques to analyze any resulting genetic sequences, comparing them to what we find on Earth.
It’s a long shot,” said MIT researcher Chris Carr, who’s working on the life-detecting device, in a statement. “But if we go to Mars and find life that’s related to us, we could have originated on Mars. Or if it started here, it could have been transferred to Mars.” [5 Bold Claims of Alien Life]
Either way, Carr added, “we could be related to life on Mars. So we should at least be looking for life on Mars that’s related to us.”
The idea that all Earth life could be descended from Martian organisms may not be fully mainstream — but it’s not too crazy to dismiss, either. While the Martian surface appears to be cold, dry and lifeless today, there is plenty of evidence that the planet was much warmer and wetter in the distant past, billions of years ago.
Here on Earth, life almost invariably occupies any niche that contains liquid water. So ancient Mars may have once supported some form of life — perhaps even before Earth did, researchers said.
Erich von Daniken had theorized that we are descended from The Stars.
He quotes extensively from mythologies,legends and Monuments that remain unexplained fully.
His postulates that Stonehenge, other marks in Polynesia and Crop circles are markers for Aliens to identify and land.
He refers to the Pushpaka Vimana of Ravana in The Ramayana as one of the types of Alien Crafts used to land in Earth.
He also states that our Genetic codes were altered and we are evolving in the way we have been programmed.
I would also state that the First Test Tube Baby was Mandatha as enunciated in The Vishnu Purana, where by mistake the King drinks the pot of Water powered by mantras instead of his wife;he begets a child;as he could not breast feed the child Indra, Chief of Devas,(Beings on a higher plane than Human Beings) feeds the Child,The Nectar with fingers.
Description Brahmastra.
..it was a single projectile
Charged with all the power of the Universe.
An incandescent column of smoke and flame
As bright as the thousand suns
Rose in all its splendor…
…it was an unknown weapon,
An iron thunderbolt,
A gigantic messenger of death,
Which reduced to ashes
The entire race of the
Vrishnis and the Andhakas.
..The corpses were so burned
As to be unrecognizable.
The hair and nails fell out;
Pottery broke without apparent cause,
And the birds turned white…
…After a few hours
All foodstuffs were infected…
…to escape from this fire
The soldiers threw themselves in streams
To wash themselves and their equipment..”
The damage to man-made structures caused by the bombs was due to two distinct causes: first the blast, or pressure wave, emanating from the center of the explosion, and, second, the fires which were caused either by the heat of the explosion itself or by the collapse of buildings containing stoves, electrical fixtures, or any other equipment which might produce what is known as a secondary fire, and subsequent spread of these fires.
The blast produced by the atomic bomb has already been stated to be approximately equivalent to that of 20,000 tons of T.N.T. Given this figure, one may calculate the expected peak pressures in the air, at various distances from the center of the explosion, which occurred following detonation of the bomb. The peak pressures which were calculated before the bombs were dropped agreed very closely with those which were actually experienced in the cities during the attack as computed by Allied experts in a number of ingenious ways after the occupation of Japan.
The blast of pressure from the atomic bombs differed from that of ordinary high explosive bombs in three main ways:
A. Downward thrust. Because the explosions were well up in the air, much of the damage resulted from a downward pressure. This pressure of course most largely effected flat roofs. Some telegraph and other poles immediately below the explosion remained upright while those at greater distances from the center of damage, being more largely exposed to a horizontal thrust from the blast pressure waves, were overturned or tilted. Trees underneath the explosion remained upright but had their branches broken downward.
B. Mass distortion of buildings. An ordinary bomb can damage only a part of a large building, which may then collapse further under the action of gravity. But the blast wave from an atomic bomb is so large that it can engulf whole buildings, no matter how great their size, pushing them over as though a giant hand had given them a shove.
C. Long duration of the positive pressure pulse and consequent small effect of the negative pressure, or suction, phase. In any explosion, the positive pressure exerted by the blast lasts for a definite period of time (usually a small fraction of a second) and is then followed by a somewhat longer period of negative pressure, or suction. The negative pressure is always much weaker than the positive, but in ordinary explosions the short duration of the positive pulse results in many structures not having time to fail in that phase, while they are able to fail under the more extended, though weaker, negative pressure. But the duration of the positive pulse is approximately proportional to the 1/3 power of the size of the explosive charge. Thus, if the relation held true throughout the range in question, a 10-ton T.N.T. explosion would have a positive pulse only about 1/14th as long as that of a 20,000-ton explosion. Consequently, the atomic explosions had positive pulses so much longer then those of ordinary explosives that nearly all failures probably occurred during this phase, and very little damage could be attributed to the suction which followed.
Time Travel, Clairvoyance, Clair-audience,Kinetasis,Telepathy,quantum Theory are described in Hinduism.Some of them are blogged by me under Astrophysics.
Chariots of the Gods -The Series is based on the books of Erich von Däniken who more than twenty years ago first presented his theory of extraterrestrial contact with the ancient world – a theory so incredible yet so logical that it has become part of a wide ranging debate that continues stronger today.
His examination of ancient ruins, forgotten texts, and other archeological anomalies points to evidence of extraterrestrial intervention in human history. Most incredible of all are von Däniken’s claims that we ourselves are descendants of these galactic pioneers and that the evidence is out there to lead us to them. Chariots of the Gods follows the adventures of the team who will attempt to do just that.
Many planetary scientists say it’s conceivable that all life on Earth is descended from organisms that originated on Mars and were carried here aboard meteorites. And if that’s the case, an instrument being developed by researchers at MIT and Harvard could provide the clinching evidence. In
order to detect signs of past or present life on Mars – if it is in fact true that we’re related – then a promising strategy would be to search for DNA or RNA, and specifically for particular sequences of these molecules that are nearly universal in all forms of terrestrial life.
That’s the strategy being pursued by MIT research scientist Christopher Carr and postdoctoral associate Clarissa Lui, working with Maria Zuber, head of MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS), and Gary Ruvkun, a molecular biologist at the Massachusetts General Hospital and Harvard University, who came up with the instrument concept and put together the initial team.
Lui presented a summary of their proposed instrument, called the Search for Extra-Terrestrial Genomes (SETG), at the IEEE Aerospace Conference this month in Big Sky, Montana.
The idea is based on several facts that have now been well established. First, in the early days of the solar system, the climates on Mars and the Earth were much more similar than they are now, so life that took hold on one planet could presumably have survived on the other.
Second, an estimated one billion tons of rock have traveled from Mars to Earth, blasted loose by asteroid impacts and then traveling through interplanetary space before striking Earth’s surface.
Third, microbes have been shown to be capable of surviving the initial shock of such an impact, and there is some evidence they could also survive the thousands of years of transit through space before arriving at another planet.
So the various steps needed for life to have started on one planet and spread to another are all plausible. Additionally, orbital dynamics show that it’s about 100 times easier for rocks to travel from Mars to Earth than the other way. So if life got started there first, microbes could have been carried here and we might all be its descendants.
If we are descendants from Mars, there might be important lessons to be learned about our own biological origins by studying biochemistry on our neighbor planet, where biological traces erased long ago here on Earth might have been preserved in the Martian deep freeze.
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