How did life begin?

Answer 1

Nobody knows this for certain yet, but the most likely scenario is:

All life on Earth is composed of organic molecules composed primarily of carbon, hydrogen, and nitrogen, such as amino acids which are common throughout the universe.

In 1953 Scientists Stanley Miller and Harold Urey conducted an experiment in which they synthesised Earth's early atmosphere in a glass vessel. This early atmosphere contained water, methane, ammonia and hydrogen. The scientists then applied energy to this primordial mix in the form of electricity. Over time, a brownish red residue composed of amino acids, the building blocks of life.

Later experiments along the same lines as the Miller Urey experiment successfully created organic molecules of increasing complexity, including adenine, cytosine, guanine and thymine - The 4 component molecules of DNA!

Such experiments were also successfully replicated using EM radiation at 270 Angstroms; Ultraviolet light, which would have been abundant from the sun since Earth had no ozone layer at the time. these experiments even produced structures which are very similar to cells. No experiment has successfully produced life as such, however they have demonstrated that the Early Earth was rich in the raw materials for life, and had suitable energy (lightning and the sun) and time for complex molecules to form in DNA.

The first proto-life would have occurred in the oceans, denser organic molecules created with the energy of the sun would have sunk in the water, protecting them to some extent from the UV radiation which could harm as well as create.

We do know that life began relatively early on Earth. the Earth formed 4.5 billion years ago. The first fossil cell structures, found in Africa are 3.9 billion years old. Complex, multicellular life does not seem to have become prevalent until about 500 million years ago.

The raw materials for life, including methane, ammonia, hydrogen, and even the structural building blocks of amino acids have been detected by spectroscopy as occurring throughout the visible universe. We don't know yet with absolute certainty what caused that first spark of life on Earth, but it would seem that the requirements for life to begin are not rare in the universe.

If you are genuinely interested in this subject, I urge you to look in more detail into The Miller-Urey experiments

Answer 2

Wow, that is a really broad question with a very long, and confusing answer.... okay, let's do this:

In the beginning (actually, after THE beginning, but about 4.8 billion years ago) there was a rock in space (well, there were many, but ignore the others for now). This rock was called Earth.

Eventually stuff on the rock that wasn't alive came to life. And that is pretty much how life began.... Yeah... okay, now that you know the basics, let me give you the horrendously long scientific details.

The Earth was pretty much a tub of a bunch of different non-living chemicals such as Carbon monoxide among many others. There was almost zero (if any) oxygen though, and this was important because... well, you'll see.
So these chemicals were just kinda there and the atmosphere of Earth just happened to be very dynamic at the time, what with lighting storms and volcanic eruptions and stuff like that. This provided energy - the energy that allowed certain chemical reactions to take place, such as those that cause the inorganic molecules to polymerize. This eventually is thought to have led to the formation of some simple organic molecules, and then to macromolecules. Certain things like lipids and nucleid acids fromed, namely RNA, the acid essential for life! Still, life did not exist.

Over many millions of years, these compounds kinda interacted with each other, until they eventually started interacting in a way that kept itself going (the reactions stuck around and kept going and going). That's the basic explanation of it, but what a book would say would be much more detailed and several pages and pictures long. Oh, and life eventually resulted from the random interaction of these ongoing reactions. It really is a tough concept to grasp just from a paragraph of text though.

BASIC SUMMARY:

People don't really know for sure (though there is a lot of evidence and it's prettty much accepted i think), but what generally assumed is that there were molecules that weren't alive that interacted with each other randomly, and these random interactions eventually led to life (really, that's pretty much it. if you think about how long it took though, random interaction suddenly becomes a lot more likely to be the cause. it's all been going on for almost 5 billion years, after all!!). To understand it all though would take a really long, graphic filled explanation. Sorry bout that dude. It took me three years of bio to fully understand it, so... yeah... but basically that's the whole process, just with a bunch more fancy science-like terms

Answer 3

This is a big question mark even for scientists. Somehow organic molecules had to go from non-life to the complexity of DNA. Evolution explains very well all changes AFTER that but how that could happen is pretty strange. That is why there is so much interest in finding life somewhere besides earth... if there is any, anywhere then life has to be more or less inevitable everywhere but if it can't be found anywhere else then something really profound happened here on earth.

Answer 4

We don't know yet. It seems to have happened fairly soon after the earth condensed to the point where life could exist, but the details are not known. We know something of the earth's condition at that point: oceans like now, huge tides (the moon was a lot closer), and the atmosphere was nitrogen, carbon dioxide, and methane. In a famous experiment, Harold Urey passed electric discharges through a miixture of these substances, and formed a number of organic chamicals which could be useful to life.

Answer 5

Amino acids exist throughout the universe, including comets. They are the building blocks of proteins. Proteins make enzymes that can copy nucleotides to make DNA. Evolution took over, driven by natural selection. Darwin was right, bless him.

Answer 6

Genesis 1:1

Answer 7

Check this idea out:
http://en.wikipedia.org/wiki/RNA_world_hypothesis

Answer 8

http://en.wikipedia.org/wiki/Miller_experiment

Answer 9

with a big 'boom' on earth 4.6 million years ago