Life means many things to many different people. Life, to me for instance, is defined as any organic molecular structure containing DNA with the means to produce similar organic molecular structures. I acknowledge that there are numerous other definitions, one of which may resonate with your personal beliefs more than the definition I have offered.
Suppose, for the sake of this discussion, that you agree with this basic definition, which assumes your belief in chemistry. A human being is created from two reproductive cells each containing one half of the DNA in each non-reproductive human cell. From this union an entire human body is produced. This process is similar in many organisms.
Human embryo 7th week of pregnancy
In a more simplistic sense, but very much analogous way, single-celled organisms reproduce either sexually (a process basically the same as the human example above) or asexually. Asexual reproduction involves the DNA of the cell replicating itself, with the help of various enzymes (protein molecules). The cell then buds off a portion of its cell membrane and contents along with the duplicate set of DNA, thus creating a new cell in the likeness of the original.
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DNA is a tricky molecule. It has the molecular coding to produce protein structures; which in turn, are sent orders and materials (energy and molecules) from the DNA to produce other structures. All of these structures have a function and a set of assembly and installation instructions to ensure they are placed in the proper location to perform their function. DNA is the central organic molecule that brings order to the surrounding environment to create life.
This is why DNA is the root of all life and why, as a compound, it is so special. From where did it come? DNA, or deoxyribonucleic acid, is a combination of building blocks called nucleotides. Nucleotides are comprised of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases. These three things are made up of Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorous atoms. Nucleotide formation is a natural chemical reaction when these atoms are present in the same time, place and given a set of proper environmental conditions.
These atoms were produced in a cosmic explosion billions of years ago when a giant conglomeration of blazing gas expelled its contents into the universe in a glorious death cry. This process occurs fairly frequently when looking at the aggregate universe even though each individual Supernova may occur after several billions of years of life for the star. Is it statistically impossible that somewhere else in the universe these atoms were joined in a similar set of environmental conditions, and produced nucleotides and so on to DNA?
I am no statistician, but I think it is actually a likelihood that DNA has been produced somewhere other than this lonely rock planet orbiting a middle-aged, inglorious star on the outskirts of the suburbs in an ordinary spiral galaxy amongst the incomprehensible vastness of the universe.
Fear not, believers in Intelligent Design, for there is a place for your beliefs in this exploration. Recently there have been some noble attempts and excellent theories postulated about the creation of the universe and the basic properties of its materials; however, none of these theories have yet to be, or even are on the horizon of being, proven through scientific observation. Thus, the set of conditions and properties of the universe which led to the creation of all that we see is still a mystery. And, given the fact that incredibly minute deviations in the properties of subatomic particles would lead to a universe that contained no matter or interaction between particles, I would say that there was a great degree of precision imbued upon the fundamental set of building blocks.
Human embryo picture courtesy of Flickr user euthman