A question on the origin of life - How did life come to be?

Question

Based on the below question,
http://answers.yahoo.com/question/index;_ylt=As4I7hF4rIY.x55U9zQk5PHd7BR.?qid=20070213105556AAasK7v
which was placed in the religion section by a yahoo answers friend,

I wanted to post this same question here in the science section in hopes of getting input from people who don't frequent our little corner of the yahoo universe - the religion and spirituailty section.

Would any of you fine persons from this section have any input as to how the first DNA could have come about, perhaps a scientific explanation?

Answer 1

Pools of amino acids collected, when energy was applied to them (say, by getting zapped by a lightning bolt) they started to build copies of each other, eventually building cells, which eventually formed living things.

Answer 2

Pfo gave a fairly good, if brief answer.

Given the volume of chemical reactions occurring during the earliest stages of Earth's development, once there was enough liquid on the surface, it would be hard for self replicating chemical reactions NOT to occur.

Picture a hostile terrain broken by pools of thick chemical enriched goo... literally tons of the stuff across even a few thousand square meters. It boils in the sun, freezes during the night, evaporating and condensing as a lifeless liquid every day for years, if not centuries.

As the forming Earth cools, there is water vapor formed and it's reactions with the turbulent atmosphere causes lightning strikes to the surface so often that, were we there, we'd be burnt to a crisp within minutes. A few strikes hit some of these pools of rich amino acids... and a few molecules attract loose atoms and they arrange along side - replicating the original. These branch off and continue.

The problem a lot of people have is lack of comprehension of the time scale involved. This does not happen in a few days - it takes hundreds of thousands of years of chance effects that lead no where and then a few repeating events. Once they repeat consistently, you have the start of privative life.

These then change according to the environment - as the radiant heat of the Earth gets further away due to a thickening crust, the sky starts to clear and more sunlight gets to the surface. This impart energy to the chemical reactions and algae results.

The first starts of life like this have been duplicated in laboratories. It is not a life that bubbles and blinks and grows - it's a thick goo that sticks to the sides of glass containers and breaks down unless exposed to the right balance of heat and further input of raw chemicals. Given a few billion years it could spawn a real life form.

Evolution does not say there is no god. It just gives the process of how life changes. The ORIGIN of life is chemical and easily duplicated. Getting it to change into something we recognize takes more time that most people have the imagination to grasp.

Answer 3

The only experiment I am aware of that attempted to model the early Earth was the Miller-Urey experiment in 1953 (probably others have been done):

http://en.wikipedia.org/wiki/Miller-Urey_experiment

The most convincing explanation for the origin of life (personally) is this:
Chemical reactions, in the extreme conditions of the early Earth, were catalyzed (by lightning perhaps), forming molecules. At some point, a certain molecule was formed that, by chemical and physical processes only, was able to replicate itself; that is, its unique structure and properties were such that nearby atoms were (physically and chemically) induced to arrange themselves into the same formation as the parent molecule. This may seem an unlikely scenario until you acknowledge the scope of geological time, and the fact that this event, although perhaps improbable, only had to occur one time.

Presumably, more than one such type of molecule was formed. If two of these self-replicating molecules were in the same vicinity, and they were made of similar elements, they would "compete" for resources (again, by chemical processes). The molecule most adept at replicating itself would take the resources for itself, leaving the other molecule in limited supply (hence natural selection).

When a molecule was formed by a parent molecule out of constituent atoms, there would be occasional copying errors (perhaps a particular atom was just not present, and so a spot was left vacant, or another atom took its place, etc.), and so a NEW molecule was born. If this new molecule were better at forming copies of itself than the parent, then you would see an increase in the number of new molecules, and a decrease in the parent molecules.

Over time (billions of years), and by way of imperfect copies and competition, molecules become more complex (too complex to be called molecules any longer), and developed better replication mechanisms. At some point DNA came about by this processes and subsequently became the lifeforms we see today.

What we know as consciousness probably came about to help animals model their environment. If you can recall a past abstract experience, say, of being chased by a predator, and you remember what you did that helped you escape, you are likely to execute the same behavior pattern, and thus help you survive long enough to reproduce. A creature without this ability will likely find itself in trouble, or worse, dead, so it can't reproduce.

Answer 4

Life was immediately preceded by an RNA phenotypic world. The bonding of complex organic chemicals into nucleic acids can take place under a variety of conditions (including laboratory conditions), and this apparently also happened early in Earth's history. Nucleic acids can combine to form nucleotides, the building blocks of RNA. Phenotypic RNA still falls short of a (somewhat arbitrary) biological definition of life. But at some stage such phenotypic RNA would have been capable of replication. The process toward life would then have moved from the mere bonding of organic chemicals into chemical evolution. But it would have been an evolutionary process with somewhat different "rules" than we see with, let's say modern vertebrate species. For example, different "species" of phenotypic RNA could have combined in unique ways. RNA is capable of storing genetic information, catalyzing chemical reactions, making proteins and replicating, so it would have been a close precursor of what we would define as "life."

The hot question now in abiogenesis research is if phenotypic RNA was the sole precursor of life, or whether protein synthesis, RNA and metabolic processes each evolved independently (evidently this is chemically possible) and then combined in a way we call endosymbiosis.

The chemical evolution of phenotypic RNA would have progressed for some time and eventually resulted in simple viral like life forms with strands of RNA some 100 codons long. The evolutionary process of such simple life would have progressed, incrementally, or perhaps by endosymbiotic leaps, to eventually become simple organisms with DNA.

Answer 5

The abiogenesis question is not even well formulated, falsifiable, let alone anywhere near an answer. Hypothesis from panspermia to clay serving as the model of replication abound. Creationists chemical arguments, such as chirality, have been well addressed of late, but the exact method that provided replicating molecules may never be know. Put abiogenesis into you address bar and make up your own mind.

Answer 6

Some folks believe it was due to the Big Bang Theory...some believe it was a supernatural force, or G-d...however, the BBT fails to explain where the original particles were generated from...and the supernatural idea fails to address the development of such a force...so to answer, no one really knows...but it's okay to have many ideas of the truth. :)

Answer 7

i dont know exatly but from a bubble of water

Answer 8

Pure luck. Anyone who says " God " is stating only on "fate of God actually being real "