Common Complaint: How did new biochemical pathways, which involve multiple enzymes working together in sequence, originate? Every pathway and nano-machine requires multiple protein/enzyme components to work. How did lucky accidents create even one of the components, let alone 10 or 20 or 30 at the same time, often in a necessary programmed sequence. Evolutionary biochemist Franklin Harold wrote, “we must concede that there are presently no detailed Darwinian accounts of the evolution of any biochemical or cellular system, only a variety of wishful speculations.”
Answer:
One of the biggest problems with this question is that it’s assuming that each component for each biochemical pathway was created/designed for just that pathway. As it turns out, the components of biochemical pathways actually serve many functions. This plasticity – known as enzymatic promiscuity – is one of the biggest pieces of evidence of the evidence of the pathway’s evolution and contributing factors to it’s continued evolution. Here’s how.
Biochemical pathways are primarily composed of enzymes (a type of protein) acting on substrates. These enzymes catalyze an action that would normally still take place; it would just act slower. These enzymes do not just do one thing; while they usually engage in one primary reaction, they are also involved in other activities that are less important. This flexibility (called enzymatic promiscuity) allows for these enzymes to be incorporated into new metabolic processes as environmental and genetic change occur.
If you really want to think logically, let’s do a thought exercise: Imagine you are building a house. With this house, you get to start from scratch. You spend a lot of time planning it out, aiming for simple solutions to complex problems. You know ahead of time how many bedrooms you will end up needing it to have, how many stories, where you want the stairs to go. You plan for energy efficiency, beauty, flow – all at the same time. Once you’ve got it planned out perfectly, you create it in a short period of time, and you’re done.
Now imagine you are remodeling a one-room house. You can only add on bit-by-bit as you need it, and you have to work with what is already available (with the exception of periodic “new” material to work with, let’s just call them, oh, mutations). Because you can’t sit there and plan it all out for efficiency ahead of time, it ends up very complicated (maybe not dissimilar to the Weasley’s “Burrow” from Harry Potter). It might even look so complicated that an outsider looking in might even think that you had planned on it being that way all along.
The first scenario is what we would expect of a “designer God” who planned out everything and then created it instantly while the second is what we would expect from a God working over a long period of time following natural laws (that he himself put in place). And what this reveals is that, far from complexity suggesting design, complexity suggests evolution. The more complicated a system is, the more likely it evolved. After all, why would a designer God have created a 15-step process to create one enzyme when he could have just engineered the perfect 1-step process? These systems are evidence for evolution. A simple, efficient, perfect design would be more indicative of a world created in 6 days designed by an all-knowing God whereas a world full of complexity – the kind of world we live in – is more aligned with a world that was created using evolution as a tool.
[1] 15 Questions for Evolutionists. Evolution: the naturalistic origin of life and its diversity (The General Theory of Evolution, as defined by the prominent past evolutionist Kerkut; see introduction to Origin of life.) by Don Batten