a life Origin
Approximately 3 800 million years ago as a result of chemical reactions the first difficult connection capable samovosproizvoditsja was formed. So the life beginning on the Earth was necessary.
life Origin on the Earth, as a whole, still remains a riddle. But since Charles Darvin has described for the first time process of evolution of a plant and animal life, scientists hold the opinion that all forms of a life are in process of constant and continuous development.
With each new generation strengths are perfected, and weak are eliminated. One kind of ancestors could generate some forms of a life then either died out, or found own niche in an ecosystem.
Judging by the found fossils, it is clear: the system of related lines between the existing and disappeared organisms reminds a tree on which eventually there are all new branches. Many of them dry up and die off (for example, dinosaurs), but other branches grow and blossom. If to track any of them to the basis, finally, we will come to a uniform trunk - to a primogenitor of living organisms all ever, i.e. To a source of an origin of a life.
Traces in rock
Unfortunately, it to make uneasy. By modern estimations, the age of the Earth makes about 4 500 million years, and to the most ancient fossils as consider, no more than 590 million years that corresponds to the beginning so-called. The cambrian geological period.
The Fossils found in breeds kembrija, include remains of various forms of a life, such as hearts and molluscs, events, obviously, from the primitive ancestors. Their origin during an epoch known as dokembry, remains not clear because in breeds of the given period has not remained any organic remains.
It is easy to explain the Reason of it. Spineless organisms do not leave fossils as, dying, usually have time to decay completely before adjournment surrounding them will turn to firm breed. Possibly, the majority of the organisms living in dokembrijsky the period (making 80% of all history of the Earth), were too fragile to leave accurate adjournment.
But it does not mean that they at all have not left traces. In the early fifties two researchers have started careful studying on coast of the lake Top (USA) of a layer of the breed having age of 2000 million of years and known as siliceous slate. In breed there were the curious white rings, everyone in diameter about metre. At first sight, in them there was nothing organic, but, despite it, scientists have decided to investigate small samples of rings by means of a strong microscope.
They have found out doubtless signs of an ancient life: remains of the tiny organisms reminding microscopic monocelled seaweed and bacteria which safely live and until now. Any wonderfully these fragile organisms have become impregnated steklovidnym kremnezemom, hardened and turned to siliceous slate where they and have remained, like flies in amber. White rings in breed have appeared dim remains of their colonies (the stony spherical formations named stromatolitami and reminding coral reeves in waters of tropical widths).
The Find of samples containing organic remains was opening. Scientists of all world have renewed studying of breeds as which they considered earlier deprived of fossils. Their efforts have been rewarded by amazing results: most ancient of found out for today to life forms (in the western part of Australia) about 3 500 million years. Meanwhile, careful studying of most ancient of breeds known to us - gneisses of Amitsoka in the southwest of Greenland which age of 3 800 million years, has not given expected results.
Biologists do not find anything surprising that the found primitive remains remind modern seaweed and bacteria. Such unicells always were considered as the elementary forms of a life, and it is quite natural that they are also its most primitive forms. Thanks to simplicity of unicells it is rather easy to find out a way of their existence. Instead of studying of the mechanism of functioning of bodies and muscles, biologists investigate, how initial chemical substances turn in "ъшЁяшёшъш" lives - fibers, fats and sugar.
the Simple cage
These researches are especially important for disclosing of secret of occurrence of a life as should take place, the following transformation which has begun all process - from inorganic chemical substances in a live matter.
The Bacterium - itself a feeding elementary cage - the jellylike cover filled with a liquid which overworks the simple chemical substances consisting of hydrogen, oxygen, carbon and nitrogen, in difficult organic connections: fibers necessary for its growth and giving to it energy carbohydrates (sugar).
The Given processes the organic substance - a deoxyribonucleic acid (DNA), finally, operates. Besides, DNA possesses one more important property: it can reproduce herself.
Each molecule of DNA reminds a spiral staircase where chains of atoms form boxing/vye of the party with crosspieces ("ё=ѕяхэіърьш"), located through equal intervals. All molecule, if necessary, can fork, thus "ё=ѕяхэіъш" are divided in the middle. After spiral bifurcation truncated "ё=ѕяхэіъш" draw other substances which, joining, form missing halves "ыхё=эшч№" - thus, from one spiral two turn out.
This simple reception is essence of a life. Thanks to it the unicell grows and reproduces itself, being split in the middle and copying thus the internal chemical process.
In more difficult forms of a life breeding cages are formed in common by the multicellular structures, thus each structure is only a part of the extremely difficult organism. All process the genetic code put in a molecule of DNA and different not only at different kinds, but also at all individuals operates.
All vital processes (meal, drink, deducing from an organism of products of ability to live, etc.) are the mechanisms serving for maintenance of activity of DNA.
DNA - very difficult molecule, and the more difficult the life form, the is more difficult than its DNA. But even the structure of most simple DNA (in a bacterium cage) consists of thousand the atoms grouped in nukleotidy - connections of Sugars, phosphates and the nitrogenous bases.
Everyone nukleotid in itself also is enough difficult structure, same concerns and other organic molecules, such as fibers and carbohydrates. So, fibers consist of chains of amino acids (20 various kinds all them), located in certain sequence. The simple chain can consist of 100 links, and difficult - from several thousand. All structure is defined by a genetic code of DNA of the given organism.
The Most simple cage of a bacterium contains fibers, carbohydrates and DNA (and other similar nucleinic acids) without which it cannot function. As these cages - most primitive of forms of a life known today, arises a conclusion that they have arisen their lifeless structures synthesising these major elements of a life still before could find of them organic application.
Nobody knows, what was our world 3 800 million years ago, but in 20th scientists Oparin and Haldejn have put forward the theory according to which atmosphere of the Earth during those far times almost has been completely deprived some oxygen, and consisted of ammonia, water, okisi carbon, methane, hydrogen and of some other substances. They have assumed that the most part of a surface of the Earth has been covered by a layer of the hot water which boiling was supported by the magma fused by breed, being under thin oceanic earth crust.
On their hypothesis, such mix of gases and hot water could lead to formation so-called "яхЁтшёэюую сѕыіюэр" rich a darkness chemical elements which are necessary for life synthesis. Reaction could be initiated volcanic activity, the intensive ultra-violet radiation passing through a thin layer of atmosphere, or the electric category of a lightning. The given theory has been checked up by practical consideration in 1953 by the American scientist Stanley Miller.
Miller has created the model of the protogenic world consisting of two flasks and glass tubes. In one of flasks there was a solution which structure theoretically corresponded to sea water. Over a liquid it has filled space with a mix of gases which, besides theoretically, corresponded to prospective atmosphere. The given flask incorporated a tube to other flask having two electrodes for reception of a spark - tiny model of a lightning. One more tube conducting to the first flask through the condenser and the P-shaped collector departed from this spark chamber.
When Miller has heated up a mix in the bottom flask, it has begun to boil, has turned to gas, has arrived in the spark chamber, and then skondensirovalas and has flown down back in the bottom flask. Process was continuously supported within a week then the liquid has been pumped out for the analysis.
Results have appeared positive: the received mix contained three amino acids - connections of which fibers are formed. Many researchers have picked up this idea, have made similar experiments and have received even more amino acids and even simple nukleotidy - building blocks of DNA.
Results of these experiments are considered convincing and give the grounds to believe that all fiber (and not only it) could be synthesised throughout several billions years. Presumably, DNA with its thousand strictly located atoms could be created even. Once having arisen, it could reproduce herself, create own fibers and other difficult organic substances and develop in the functioning self-reproduced form of a life, such as a bacterium cage.
Something similar could occur, but mathematical probability of creation of such difficult substance, as fiber or DNA, as a result of casual connection of chemical elements in "яхЁтшёэюь сѕыіюэх" infinitesimal.
The Given theory is recognised today by many scientists continuing search of the mechanism which would promote connection of amino acids (similar received in Miller's laboratory) in fibers without management from outside DNA.
If such mechanism is found, we will take the important step on a way to understanding of a riddle of formation of DNA and, hence, life origins.