The confusion of the origin of life and evolution, two very different things, is mainly due to the agenda of the some religious groups. I will explain, starting with evolution which is contrary to a literal interpretation of the Bible.

We define ‘life’ as based on cells. Life is an organised environment separated from outside by a semi-permeable membrane. It has an innate drive to survive and reproduce, and has the ability to acquire resources and to reproduce itself.

The original cells could find food, eat and divide into two by replicating themselves, including the template for doing it again: DNA. Later life got more complicated in several ways, including multicellularity and sexual reproduction.

Evolution is about how and why life got more complicated. It is a process that can only take place in living cells. It depends on the replication of DNA. It doesn’t involve anything before cells existed. The point of reproduction is to produce perfect copies. The reproductive process is good, but not perfect. The cell has many repair mechanisms for when occasional errors occur during replication, but some mistakes do happen.

DNA is a very big organic macromolecule. It is reasonably stable, but like any chemical, it will react under some conditions. Enter the environment. Earth’s surface is subject to natural radioactivity from within. It also under a constant rain of cosmic rays (actually particles). These active particles can penetrate cells and produce free radical which are very reactive. This is the source of some of the errors that can occur in DNA.

The errors that occur are random; they can happen anywhere in that huge macromolecule. The errors that get through, from internal or external causes, are what we call mutations. Mutations are why a population has a range of genetic variation. And without mutations and consequent genetic variation, evolution cannot take place.

But what are the consequences of mutations. The parent has survived and reproduced. Therefore it has the genetic makeup that works well enough in its environment to do that. A mutation changes the genetic makeup. It might have no effect - there are places along the DNA where a simple change doesn’t affect function. If it does have an effect, it can make the offspring a little better or a little worse at surviving and reproducing.

Over time and generations, those that are a little better outcompete the others and produce moe offspring and become the population. And this continues, generation after generation, with random mutations, every now and then, producing offspring a little better adapted to the environment. This is natural selection.

The environment can be stable for long periods, but it can change randomly and unpredictably, for example by an asteroid crashing on the planet, or the movement of tectonic plates, or wobbles of the Earth’s axis. This means that an organism finds itself less suited to the conditions.

This is where the those random genetic variations in the population, exposed to the random environmetal variation come into effect. The conditions work to select those that are best fitted to survive and reproduce. Either in stable conditions or through major environmental change, natural selection acts on the available genetic variations to modify the population to favour those better fitted to survive. If a population does not have the genetic capacity to adapt sufficiently or quickly enough, it becomes extinct.

This process of evolution is continuous in all organisms, usually far too slowly for us to observe directly. There is, however, a huge body of evidence for this process - what Darwin called ‘descent with modification by means of natural selection’. We have continued to collect data, to review and refine our understanding of evolution. That it is the explanation of how life has developed and diversified is unassailable, and that is what leads to difficulties for some religious people.

There has been an unrelenting attack on evolution ever since Darwin. This is most obvious in the USA, where there is a powerful religious conservative lobby, including fundamentalists: those who take the Bible to be the literal word of God. Evolution does not fit the Biblical view of life created in its final, unchangeable form, or of humans being unrelated to animals.

For almost a century, there have been legal attacks on teaching about evolution in schools. In the last 50 years as the population became more educated and enlightened, legal restrictions on teaching about evolution were removed. In 1968 legislation banning the teaching of evolution was struck down because it violated the First Amendment to the Constitution.

The anti-evolution response was to come up with an alternative they called creation science. This relies on an interpretation of the scientific evidence validating evolution to support the Biblical account, particularly the creation myth and flood story in Genesis.

Creationism created explanations to refute data from biology, geology, cosmology, archaeology, history, linguistics, physics, even dendrochronology (measuring tree age by annual rings). The new legal approach became to promote equal time for creation science whenever evolution science was taught. This was dispensed with in 1982, when the US Supreme Court determined that creation science was not science because it had none of the necessary elements of science (e.g. explained by natural means, testable, open to change).

The next attempt was the invention of intelligent design (ID). This was an attempt to redesign creationism in non-religious language. Some of the literal interpretation of the Bible was moved out of the discussion. Instead of God, an Intelligent Designer was responsible for creating life. Arguments were put forward based on ‘irreducible complexity’, that is, many chracteristics of life could not have developed through serial incremental changes so must have been designed.

The approach here was that ID was legitimate science, unconnected with a religious agenda. Again, in 2005, this failed before the US Supreme Court, which indicated that the ID was simply re-badged creationism intended to get around the First Amendment.

The classic example to support ID is the eye, the argument being that either an eye works or it doesn’t and any intermediate steps would not function, so eyes could not have arisen by natural selection. It must have been designed. This was refuted by science, demonstrating that functional vision existed at each stage from the original light-sensitive cell to the vertebrate eye.

The evolution of the eye also supported the random and imperfect processes of natural selection, not intelligent design: "Moreover, the eye contains a big flaw: the retina is inside out. Why would an almighty designer do such a thing? No intelligent designer, .. would put such a clumsy arrangement in a camcorder, and this is just one of the hundreds of accidents frozen in evolutionary history that confirm the mindlessness of the historical process." ~ Daniel Dennett

Of course, those who believe in their version of faith cannot accept the reality of evolution. They do not retreat from opposing the teaching of evolution. There is another aspect of biological science, though, that has none of the certainty of evolutionary theory.

Abiogenesis - the development of life from non-living origins - is still an unknown. There are hypotheses, based on some of the steps we know must have occurred, but we don’t know how the first cell formed. We know the precursors of macromolecules were present. We know that polymers will form and that nucleic acids can self-replicate and we know that phospholipid bilayers will form cell-like globules.

But we don’t know how those things came together to form proto-cells. We have hypotheses about it beginning with an RNA world, with RNA filling structural and enzyme roles as well as genetic material, later superseded by the DNA world we know. We don’t know how, but we know it happened. Before cellular life, we do not yet know.

If you have lost on every front to stop the teachings of science that underpin evolution, what are the options? The option the anti-evolutionists lit on abiogenesis. Science didn’t know. Here was an avenue of attack, and the attack went like this: “scientists can’t prove that God didn’t create life, so how can they expect us to believe in evolution?”

Most people outside scientists have only a general notion about biological processes, and no reason to disbelieve a well-presented, articulate story told by someone in a position of respect or authority. However, because we don't know yet is not an automatic evidence that God did it, if we should settle for the God fallacy then we never know, we wouldn't have known a lot of things that we know today.