I appear to have several fundamental points that need to be consolidated before we can move on. The Origin of the Eye, the relevance of Abiogenesis to the theory of evolution, Abiogenesis as a working model and the teachability of evolution in school being the most important ideas of this discussion, I will attempt to focus my thoughts on these topics. (It might be hard to do so- I like to digress.)
Evolution is the only scientific theory to adequately explain the diversity of life on earth. It is supported by all known data. The theory makes accurate (accurate!) predictions about the natural world. It isn’t just abstract theorizing anyway. Evolution is used in the medical sciences to invent treatment options and in the agriculture industry to maximize crop yield/acre. This is big business. And it is fact. Evolution is acknowledged “by every serious scientist” as absolute fact. It is a theory, and so is supported by many, many independent observations. It is practical. It is used to better the standard of life for millions every day. There is no argument to be made for removing it from curriculum, because it isn’t in doubt. This is the most important thing you can learn from this. Evolution, as a scientific theory, is not currently, and will not in the foreseeable future be put in enough doubt to remove it from schools on the grounds that it is not backed by evidence.
Abiogenesis most likely occurred underwater, in hydrothermal vent systems. These would be similar to the deep-ocean floor hydrothermal vents that are only now being explored and understood. My explanation is necessarily technical, but this is what is said in both Aquagenesis The Origin and Evolution of Life in the Sea, by Richard Ellis, and a potential explanation given by Genesis The Scientific Quest for Life’s Origin, by Robert M. Hazen. Cells are surrounded by membranes. A major stumbling block to the formation of protocells and primitive life was the creation of a membrane composed of lipid (fat) molecules. The formation of nucleic acids, according to John Howland, would have happened simultaneously. A hot spring on the ancient seafloor constantly spews water already percolated through rocks and clay of the seabed, and so is rich in nutrients. Also, clay particles would be suspended in the outflow. (If you watch NOVA, you’ll notice that the vents put out dark, murky water.) The clay particles transported molecules essential to life: amino acids and nucleotides, and the polymers they are made into, polypeptides and polynucleotides. There would also be some lipid molecules present, soluble in hot water but not in cold. As the heated, protolife rich water hits the cool seawater, the lipid molecules would “precipitate from the solution, forming spherical vesicles. If some fraction of those vesicles contained some of the suspended clay particles inside, with their burden of bound amino acids, nucleotides, and so on, the stage might be really set.” (Aquagenesis, quoting another researcher- John Holand) Essentially, the emissions from deep ocean vents would be ideal for the formation of life. The lipid molecules would “neatly surround” the whole amalgamation of life’s building blocks. Voila. The first cells. This sets the stage for the emergence of true cellular life, and evolution takes it from there.
Note: I plagiarized mercilessly for the scenario in this case. I am out of my specialty, but I want you to understand that scientists who specialize in this area aren’t just making things up. There is an immense diversity of data, much of which has yet to be explained. (Also, these books are cool- more people should know about this stuff. Genesis has a scientist building a “pressure bomb” with the same concussive force, should anything go awry, as a stick of TNT.)
Regardless of Abiogenesis’s eventual fate, be it positive or negative, Evolution continues and will continue to be a valid theory. If Abiogenesis is shown unequivocally to be false, then evolution will still be accurate. Evolution describes the change of organisms over time, not their origin. Ultimately, Evolution will, and can, stand on its own merits. The evidence has spoken.
The Eye
It has long been the favorite instance of “irreducible complexity” by the opponents of science. It isn’t a good example, but maybe I should explain why.
Irreducible complexity refers to a structure, any structure, that is completely non-functioning without all of its component parts. An adaptation that could not have come about by steady improvement, constant gradations, and gradual change would be the apparent bane of evolution. For as long as there have been opponents to evolution, there have been claims of irreducible complexity. For a while it was the wing. And the eye. And bacterial flagella. And then it was the clotting system. There has not been a single example of an evolutionarily unattainable adaptation. Ever.
The eye is a good one because it seems so specialized. There is the retina, the pupil, it is in exactly the right shape, and above all, it works. The unimaginative can only wonder and say “God did it.” I say differently. There are examples of light sensitive organisms that do not have vision as we experience it. There are examples of primitive vision, such as algae that use their light sensitivity to find or avoid sunlight. Many microorganisms have some sort of photosensitivity. Even some modern plants have rudimentary photoreceptors. (Not to mention the cells that take part in photosynthesis.) Light reception is by no means the exclusive domain of complex and camera style eyes.
Because the eye is active and useful at every level of efficacy, from the faintest hint of vision to the clarity and perfection of a hawk, it fails to qualify as an example of irreducible complexity.
Evolution has a ready and logical answer to every question yet asked of it. There has been no example of irreducible complexity, nor has there been any proof for the null hypothesis: Creationists can not support their own claims. There is no sound argument against evolution, unless one starts with the premise that it is incorrect, usually founded on religious conviction. We can’t teach religion in schools, and we can’t teach creationism.