EARTH IS THE AIM 7 , Mu and the other worlds , Chapter 6 : Emmergence of Life on Earth

Earth is the aim 7

Mu and the other worlds

 

Chapter 6 : Emmergence of Life on Earth

 

The Miller-Urey Experience

In 1953 Stanley L. Miller, an American biologist, became famous thanks to his Miller-Urey experiment, on the chemistry of the origins of life on earth in the original ocean , named soup

This experience enabled him to prove that on Earth, about 4.3 billion years ago, the original ocean contained the chemical elements necessary for the creation of proteins and DNA, the constituents of life

 

He put methane, ammonia and hydrogen in a flask filled with water and heats it to boiling point

By means of a condensation column, the vapors then pass into a second balloon where they are permanently bombarded by flashes produced by electric arcs

At the end of a week, organic compounds appear, of which 2% are amino acids, base of all the protein chains, therefore potentially of the life

 

We know today that the primitive atmosphere of the Earth was not that of experience, but these results triggered a great deal of research

 

 

Research on the emergence of life on Earth

Critics arrived immediately on this theory, saying that the amino acids could have originated from a contamination, but these results were corroborated three years later by new experiments

 

Five years later, in 1958, Miller realized a new experiment using other gases, notably hydrogen sulphide, recreating conditions closer to those around the volcanoes, but did not have time to re-analyze the results

The compounds created by the experiment were kept in his laboratory and were found at his death fifty years later

 

In 2008, thanks to mass spectrometry, the analysis of these compounds allowed the discovery of the twenty-two amino acids necessary to the life and the assurance that they could well be created in the primitive soup of the Earth

 

Since then, many researches have reinforced and completed the theory of the appearance of life on Earth in the original soup

The role of sulfur, electrolysis and the magnetic field in the creation of amino acids, are the steps towards the living

 

The Original Soup

It is still unclear what chemical elements were present in the Earth’s atmosphere and water about 4.5 billion years ago, but we have now a good idea about it

 

The Earth’s atmosphere was made by numerous elements sent by the Sun, comets and meteorites, to which are added the elements produced by the intense volcanic activity

We should have then :

Hydrogen, methane, ammonia, carbon dioxide, nitrogen, potassium, magnesium, sulfur and of course water vapor

These elements have been slowly deposited in the water creating the primordial soup

In this warm soup, the precipitated elements could evolve towards the living

 

From soup to cell

If you wish the soup be good, you have to turn it …

This is what the Earth has done with its magnetic field

 

The magnetic field of the Earth generated a current in this original soup but also attracted in this current, by magnetization, its various components

The components gathered attracted preferably the flashes of lightning, creating a quasi-permanent electrolysis

The transformations have then begun to arrive at the amino acids, constitutive elements of the proteins and of any living organism on Earth

 

Then combinations of elements created coherent assemblies, the coacervates

Coacervate comes from the Latin: coacervare which means to gather, to put in group

It is a spheroidal droplet of suspended particles

The coherence of the droplet in the current is ensured by the magnetic magnetization of its non-soluble components

 

Coacervates measuring 1 to 100 micrometers in diameter and are spontaneously formed in this soup

They then capture other molecules that will allow it to create a flexible membrane that will close on its components

The coacervates driven by the current, will continuously capture by osmosis new components

After a certain time, the coacervate which has accumulated too much material becomes too large until tearing its envelope

It will then split in two to and form a new coacervate separated from the initial coacervate

Thanks to the high concentration of compounds in the original soup, the new coacervate will in turn enrich itself with the free compounds floating in the magnetic current

 

Alexandre Oparine, who studied coacervates, discovered that in the presence of catalysts, the coacervates exchanged substances with the outside world, enlarged and multiplied

 

Hence the importance of the magnetic field, which will serve as a trap for components, container, catalyst and activator

 

From cell to RNA

Increasingly complex populations of molecules have then populated the coacervates

 

At this stage, the molecules can bind together according to ordered sequential patterns and thus form chains by polymerization called PolyA

Thus, thanks to the harvest in the primitive soup of nitrogenous bases, sugar (ribose) and phosphate (inorganic pyrophosphate), the primitive RNA molecules will be formed

These intakes stabilized the RNA molecules

 

The RNA, ribonucleic acid, is a molecule containing 1 strand composed of a chain of nucleotides

A nucleotide is an organic molecule composed of a nitrogenous base, a sugar and one to three phosphate groups

 

This stranded configuration allowed the RNA to fold back on itself and thus certain complementary sequences could be linked together

These looped folds gave it a better resistance to degradation and the possibility of replication by the formation of a second strand

 

New bases will then cling by affinity rather than randomly and thus form new RNAs

Among the new breeders, some of them will have a catalytic activity, and will be able to serve as a support of genetic information, it is the ribozymes

 

This catalytic activity will give them the ability to self-replicate

RNA capable of replication will then proliferate to the detriment of the others

Natural selection will begin

 

Some RNAs will bind with an amino acid, which will protect them from degradation

Increasingly, they will then prefer to bind themselves

By combining them, they will form a longer RNA

 

From RNA to DNA

At this stage, the RNA is armed with peptides, polymers or associations of amino acids, which will allow him to create an enzyme that will allow it to make the DNA

This operation, the reverse transcriptase, will, from a single strand of RNA, create a double-stranded DNA molecule

 

DNA will then evolve to store the primitive genes and thus be at the origin of all the other molecules of the living

The DNA constituted by a chain of nucleotides will provide the information necessary for the synthesis of proteins

It is first transformed into messenger RNA, it is the transcription

Then the ribosomes will synthesize the proteins by decoding the information contained in the messenger RNA, it is the translation

 

Of course, the first auto-catalytic systems were not as elaborate

But the primitive molecules had the capacity to evolve

The many contributions of new elements have allowed them

And these evolutions are inheritable, because once incorporated into a self-catalytic network, a molecule becomes capable of reproducing

 

Their auto-catalytic technics have then been perfected until they have reached the technics of DNA replication and the manufacture of the proteins that have characterized for billions of years all living organisms

This universal mechanism is the proof of the common origin of all living organisms

 

From DNA to Prokaryots

Then the cell contains DNA, a tool that allows it to transmit its characteristics to its offspring

This cell has become a bacterium

 

Prokaryots are primitive bacteria:

They are monocellular organisms

They have colonized all the environments, even the most hostile and are the most numerous organisms on Earth

 

Prokaryotic cells contain a single compartment:

The cytoplasm

It contains a circular DNA molecule called nucleoid

They replicate by cell division

In a favorable environment, bacteria can multiply at a very high speed :

The bacteria population can double every 20 minutes!

 

The most common prokaryot is Escherichia coli

This bacterium composes about 80% of the human intestinal flora

The majority of E. coli strains are harmless, only a few are pathogenic

But it could be the cause of food poisoning by the consumption of badly cooked or raw consumed animal products

Fresh fruits and vegetables which have been in contact with these strains may also be a risk, hence the need to wash them before consumption

 

eucaryotes

Ring of Life = Prokaryotic phylogenetic tree + Symbiogenetic origins of eukaryotes

Photo Wikipédia CC : Maulucioni

 

In their evolution, they will be divided into 2 groups, arches and eubacteria, finally becoming eukaryots

The archaeobacteria will colonize the extreme environments because they can survive with very few resources and are adapted to the high temperatures

Eubacteria, close to current bacteria, are adapted to warmer temperatures and have thus been able to conquer less warmer environments

 

The arches

Archae, from the ancient Greek Archaea, the original signification, are prokaryotic unicellular microorganisms, made up of a single cell that does not include nuclei or organelles

 

The Archaea generally have a single circular chromosome which is found in the cytoplasm

A chromosome consists of DNA molecules and proteins

It is the support of the genetic information that will be transmitted from the mother cells to the daughter cells

 

Archaea are found in ocean hydrothermal springs, hot volcanic springs and salt lakes

They have also been discovered in the soil, sea water, swamps, intestinal flora and even in the human navel

In the oceans, arches are part of the plankton

It is one of the most abundant groups of organisms on earth

 

The archae are involved in the carbon and nitrogen cycle

Methanogenic Archaeas of the human intestine and ruminants participate in digestion

 

Bacteria

Bacteria are cells without nucleus or organelles

There are about 10,000 species known to date, but the estimated number of species would range from 5 to 10 million

 

Bacteria are present in all types of biotops

They are of considerable importance in biogeochemical cycles, such as the carbon cycle and the fixation of nitrogen in the atmosphere

Inside the humans, 1012 species of bacteria colonize the skin, 1010 species of bacteria colonize the mouth and 1014 species of bacteria colonize the intestine

There are ten times more bacterial cells than human cells in the human body

Most of these bacteria are harmless or beneficial to the body

However, there are many pathogenic species

 

Bacteria are involved in the wastewater treatment process, in the manufacture of yogurts or cheese, and in the industrial production of many chemical compounds

 

There are about 40 million bacterial cells in one gram of soil and 1 million bacterial cells in one milliliter of fresh water

It is estimated that there would be four to six quintillions, or between four and six trillions billions billions of bacteria in the world

 

In 2007, a drilling in the Canadian permafrost allowed the discovery of a bacterium that was about 500,000 years old and still alive

 

Pathogenic bacteria can cause infections

If some pathogens bacterias cannot survive outside their host, others will create an infection by penetrating a wound, or by contaminated water, or infect weakened individuals, particularly in hospitals

 

In summary, a bacterium in its place is almost always useful, but displaced, it is most often harmful

However, pathogenic bacteria attempting to invade a host will encounter many defense mechanisms

 

Pathogenic bacteria are not only for humans and animals, but also for plants

This is how bacteria can replace pesticides to replace plant pests

 

The eukaryotic cells

In prokaryots, to protect DNA and isolate it from the environment, the cell will place the chromosome in its cytoplasm

In eukaryotic cells, evolution will create a nucleus and place inside the chromosome

 

The difference between prokaryots and eukaryots is therefore that the genetic material of the prokaryots is grouped in an area physically not separated from the rest of the cell, whereas for eukaryots it is contained in an organelle, the nucleus

The eukaryots have thus become multicellular organisms

The eukaryotic cells are delimited by a membrane for the animals or by a wall for the plants

 

Do not confuse eukaryots with viruses which are acaryots

Acaryots are elements, not cells, that have no nuclei or cytoplasm and can only reproduce by parasitizing a host cell

 

Appearance of Life on Earth

– 4.56 billion years: Earth formation

– 4.50 billion years: Liquid water covers the surface of the Earth, original soup is ready

– 4.30 billion years: The process of life begins with amino acids and organic carbons

– 4.00 billion years: First prokaryots

– 3.50 billion years: First bacteria

 

As you can see, it took just a billion years to go from the original soup to multicellular life …

Then it need another 2 billion years for the explosion of biodiversity

And then another 1.5 billion years to arrive at the men of today

 

Space, the origin of life on earth

Although there are still many unanswered questions, we begin to glimpse the origin of life on earth

 

Life appears on earth probably about 4.3 billion years ago

The Earth recovered by the water of the comets that plant themselves on its ground would then inoculated particles able to evolve towards the living

These particles would also have been deposited by comets

 

NASA astrobiologists have detected amino acids on meteorites and comets

Many scientists believe that the first amino acids would have been delivered to us by meteorites or comets and would therefore have been at the origin of life on Earth but it sure was same on other planets

 

Then life must also exist on other planets, but not necessarily like as on Earth

The evolution which may have taken place is necessarily consequent of the physical conditions of these planets

That means that a small green man or a smart saurian coming from space are quite plausible

But life can take many other forms

 

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About DOUGLAS MOONSTONE

money is the human predator
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