how did life begin on this planet?

Answer 1

This is a great question as it calls into question a fundamental principle of Biology - that life can only come from other life. If life started on this planet all by itself, then life can obviously come from non-life. As far as I know, it has been shown that amino acids (the building blocks of proteins) can be formed using electricity and a "soup" of compounds thought to be common on the early Earth... but forming an amino acid (or even a protein) is far from forming a living cell - and nobody has ever been able to show how the first cells came into existence. It is possible that life was transported here by a comet/asteroid - but that only begs the question - "how did the cells from the asteroid/comet form?" - and you are back where you started.

This is a question that will probably not be answered by science in our lifetime. Religious explanations are not scientifically valid - but that doesn't mean that they are wrong, it just means they are not scientific. Personally, I would like a scientific explanation... I'm happier knowing that I do not understand something than knowing that I believe in magic (religious creation).

Answer 2

In the beginning there were two turtles...
Well, which explanation do you want--hairy thunderer or cosmic buffoon?
Seriously, though--it's been known for a long time that a soup of hydrocarbons in an atmosphere of mostly nitrogen but with some other gases can be subjected to an electric discharge and create various organic compounds. They've also noticed organic compounds in the substance of comets. Research those two; it should keep you busy for a while. I don't think anybody has the pathway mapped out yet, they've only found a few stepping stones so far.

Answer 3

I believe in the theory known as 'comet theory'. According to that theory there must have been some form of unicellular structural organisms which was living some where in the other part of the universe. The comets have been researched and have been proved that comets has the capability to withstand life. So the planets with life may have hit my a type of comet which toke of some organisms. And they might have hit our planet Earth in the developing stage and must have scattered the unicellular organisms on over. These organisms evolved through the years. Thus, life started on earth.

Answer 4

To understand how life originated on the Earth you should first understand the Chemical Evolution of life putforth by a person by name Alexander- I -Oparin.He explained this in his book named Origin of life.In this theory the solar system originated about 5 billion yrs ago by a rotating cloud of hot gases called nebulous.This mass exploded with a big bang into several pieces calle nebulae.Earth also originated from this.The fragments which gave rise to earth was very hot.So as the nebulous cooled less volatile metas like iron and nickel condensed due to gravity and formed the Earth's crust.While the lightest elements like He,H,N,O formed Earth's atmosphere.As the Earth started cooling simple atoms like H,N,C,O formed simple compounds like methane ammonia
N+3H2----->2NH3
C+2H2----->CH4
H2+O-------->H2O
As the earth's temperature was very high NH3,CH4 remained as gases while water converted to steam.As cooling continued water vapour condensed to form clouds.Hence it began to rain.But the earth's atmosphere was still hot the liqid water vapourised and returned to the atmosphere.This happened for many years.As a result of the frequent rains ridges were carved on the Earth and this became rivers and seas until the Earth could contain liquid water.The rainwater dissolved atmospheric ammonia,methane and salts which were carried to the seas.
There was no molecular atmosphere.Then the atmospheric gases gave rise to simple molecules like aminoacids,monosaccharides etc.Then these simple molecules gave rise to macro molecules and the first gene was formed.The from that a cell was formed and thus the first form of life was in the oceans.They were a sort of organisms like cyanobacteria which could carry photosynthesis.Thus they liberated oxygen.The more complex organisms came into being like Invertebrates,Amphibians,Reptiles,Fishes etc........

Answer 5

No one knows at the present but promising research shows the likely ways.

Methane and Carbon Dioxide exposed to strong sunlight is thought to have formed an organic haze that may have produced many tons of organic materiel that fell to earth. This would have provided building blocks and a food and energy source for early life.

In a report last year in the Journal of the American Chemical Society, scientists showed that parts of the Krebs cycle can run in reverse, producing biomolecules that could jump-start life with only sunlight and a mineral present in the primordial oceans. They were able to demonstrate that three of the five chemical reactions in the reverse Krebs cycle worked and produced biomolecules on the surface of a mineral believed to have been present in the waters of the early Earth. The mineral sphalerite acted as a photocatalyst that worked with sunlight to foster the chemical reactions.

The Krebs cycle is a series of chemical reactions of central importance in cells. Part of a metabolic pathway that changes carbohydrates, fats and proteins into carbon dioxide and water to generate energy.

A reverse version of the cycle, which makes enzymes and other biomolecules from carbon dioxide could have produced the fundamental biochemicals needed for the development of more advanced biological systems like RNA that could reproduce themselves.

Chemists at Yale now report evidence that nature could have used a different building block -- beta-amino acids -- and show that peptides assembled from beta-amino acids can fold into structures much like natural protein. The importance of this is that they were able to show they could form naturally in the earths atmosphere.

Space

Organic globules found in Tagish Lake meteorites were found to have very unusual hydrogen and nitrogen isotopic compositions, proving that the globules did not come from Earth.

The isotopic ratios in these globules show that they formed at temperatures of about -260° C, near absolute zero. The organic globules most likely originated in the cold molecular cloud that gave birth to our Solar System, or at the outermost reaches of the early Solar System.

The type of meteorite in which the globules were found is also so fragile that it generally breaks up into dust during its entry into Earth's atmosphere, scattering its organic contents across a wide swath. If this type of meteorite has been falling onto Earth throughout its history, then the Earth was seeded with these organic globules at the same time life was first forming here.

Whether life formed here or from building blocks from space, one thing is now fairly certain - it came about in a natural process that is just as much part of evolution as the origin of species.

Answer 6

As per biochemical evolution theory (eurey and miller), life is originated from the chemical substance like ammonia, oxygen and corbondioxide. these basic subsance in the paleoearth produced aminoacids by the action of lightening during the time of rainfall. from this aminoacids protovirusus were formed. and the evolution progressed till now and going on.

Answer 7

There r 2 theories about it one says the Lightning and the sea water with some dissolved chemicals started life second says the volancanic eruptions inside the seas started it I can explain if u want mail me.

Answer 8

first of all earth was a hoted gaseour sphere..gradually it become cool .it takes thousands n thousands of year..by the combination of hydrogen and oxygen water forms. n fall in to the earth surface.it get evaporated as soon as it comes to earth surface due to its head. after a long period it cover the earth surface . from this water life begins as the jeli. then evolution takes place n now what we see is the life...

Answer 9

After the formation of the Earth, when the Earth cooled slowly and gradually very small unicellular organisms came into life. Slowly, after millions of years, they evolved slowly, all the life forms were formed that we see today.

Answer 10

first step towards origin of life was formation of compounds such as methane,simple sugars, fatty acids, amino acids.These were the important things in formations of life.Some people believe that life started from non living things.