Biology 101
Life On Planet Earth
6 April, 1998

According to Gould, the average complexity of most organisms has not changed much in the past 3 billion years, since life first evolved. However, it is certainly true that for a FEW organisms (such as plants & animals), the complexity has increased dramatically in the past several hundred million years.

Furthermore, I should add that, although bacteria might not be anatomically complex (that is, they're quite simple, single celled organisms), there is certainly a pretty sophisticated level of biochemical complexity within the metabolic pathways.

Overview of the E. coli Metabolic Map This diagram provides a schematic of all published pathways of E. coli metabolism in the EcoCyc database. Circles represent metabolites; lines represent reactions. Move the mouse over a circle to identify it; click on a circle to navigate to the pathway. Instructions EcoCyc query page Copyright © 1998, Pangea Systems, Inc. All Rights Reserved.

Where did this complexity come from?

In my opinion, there are 4 different views on the origins of complexity:

1. Natural Selection ("gradualism", or traditional Darwinian evolution. One of the more recent neo-Darwinists is Richard Dawkins). Remember, there are THREE MAIN criteria necessary for evolution to occur via natural selection (see lecture notes from 25-Feb-98).

	Evidence FOR Natural Selection: The FACT that evolution can occur by natural selection is no longer really questioned by most biologists - but whether natural selection ALONE can explain the evolution of complexity is a different issue.
	Evidence AGAINST Natural Selection: Even Darwin himself strongly objected to the idea that Natural Selection can explain ALL aspects of evolution - in particular the apparent "directionality" towards complexity. I personally have a difficult time with Dawkins' assertion that we are mere vehicles for DNA to replicate itself - surely there must be more to life than this!

2. Natural Selection + additional factors, such as the environment - this would best be exemplified by Stephen Jay Gould's and Niles Elderidge's PUNCTUATED EQUILIBRIUM theory, which holds that natural selection only works in short spurts amongst long relatively stable periods of stasis, lasting hundreds of millions of years, in which species don't change.

3. Intelligent Design - perhaps this is another attempt for the Creationists to hold on to their concept that God HAD to have stepped in and helped life develop. Once recent proponent of this idea is Michael Behe, in his book "Darwin's Black Box: The Biochemical Challenge to Evolution". His reasoning is as follows: biochemists have found that there are certain very complex systems (see the E.coli metabolic pathway above, for example) that are "irreducibly complex". His famous analogy is that of the mouse-trap. You need all the components for it to work. As I've stated in class, I think if God were to show Himself to us as scientists, there'd be a lot of dead scientists around, because "no man has seen God, and lived". I have also read two other "neo-Creationist" books recently. (I say "neo-Creationist" because there has been a more recent movement amongst some theologians to distance themselves from the "young earthers" who believe that the earth is less than 10,000 years old.) Over Christmas, I bought and read a book by Phillip Johnson, called "An Easy-to-Understand Guide for DEFENDING DARWINISM by Opening Minds". Johnson quotes Behe at length (although he seems to think that Behe is a "molecular biologist"), and uses the same type of logic - since life is so complex, there MUST have been a divine creator. I guess I really have problems with his view that the creationists have become the victims of the atheistic press. I wasn't that impressed with this book - I certainly have no problems with open minds - but I'm not sure that saying I already know the answer before I do an experiment is really being open minded.

I am presently (April, 1998) reading "The Science of God : The Convergence of Scientific and Biblical Wisdom" by Gerald L. Schroeder. I have to admit, that it is better than I had thought. It is written by an Israeli physicist who is also spent a lot of time talking with Jewish theologians about Genesis. While I certainly would not consider myself to be a creationist - I think Schroeder does perhaps one of the best jobs I've seen of presenting a rational, palatable perspective on creationism. Basically he says that God still allows for us to have a free will and that it is often not THAT obvious that God is at work in creation. I think he pretty much takes the view that the evidence is there for those who choose to see it, but it is not so overwhelming that anyone who is rational has no choice but to believe. Schroeder uses Einstein's theory of relativity to estimate that, relative to the initial creation event, the 6 days referred to in Genesis represent 6 major geological events, from the creation of the universe 15,000,000,000 years ago, to the formation of our solar system 5,000,000,000 years ago, to the first bacterial life in the oceans 3,000,000,000 years ago,... to modern man. He seems a bit more modest than many of the other creationist authors I've read - basically Schroeder explains his point of view, but then also explains why other people could be skeptical of what he has said.

Evidence FOR Intelligent Design: I think even Richard Dawkins would not deny that complex organisms are designed. (Of course Dawkins would say that it was NATURE doing the designing, not God - but who is he to say what God can and cannot do??) To their credit, the Creationists DO try to fully explain the reason why we see the sudden appearance of complexity, and also they provide a good explanation for the apparent "directionality" towards complexity.

Evidence AGAINST Intelligent Design: To be honest, it seems most of the time the "evidence" for intelligent design is more an appeal to ignorance. For example, Behe will say things like "no one has published a single paper about the evolution of flagella". Even if this was true, it does not at all necessarily imply (as Behe insists) that there is evidence of divine intervention (in fact there's been HUNDREDS of papers published on this subject, but Behe chooses to ignore them!)

4. "Complex Adaptive Systems" - or "Self-organising complexity" - which holds that once a certain threshold of complexity is reached, it is possible to obtain "spontaneous" Self-organisation. Perhaps one of the best examples of this is a recent book by Stuart Kaufmann, "At Home in the Universe : The Search for Laws of Self Organization and Complexity", and his other book "The Origins of Order : Self Organization and Selection in Evolution". The idea of complexity comes from a variety of other sources, including Chaos theory (e.g., James Glick's CHAOS), artificial intelligence ("HIDDEN ORDER: How Adaptation Builds Complexity", by John Holland), and from a broader perspective on human consciousness ("Darwin's Dangerous Idea - Evolution and the Meanings of Life", by Daniel Dennett).

see also, M. Mitchell Waldrop's "Complexity: The Emerging Science at the Edge of Order and Chaos"

Evidence FOR Complex Adaptive Systems: There are many systems that obviously fall into this category. The real question is whether these types of systems can be used to model the evolution of complexity. I think the preliminary results seem to be in favor of a very useful mathematical tool for understanding the behavior of complex adaptive systems, including evolution. I am not sure if this can really explain FULLY the drive towards more complex systems seen in evolution, but it seems like it is perhaps a good hope for a scientific explanation.

Evidence AGAINST Complex Adaptive Systems: I am not aware of any major problems with this, although it is still a bit young, and perhaps a bit theoretical.

SUMMARY

In summary, I think that perhaps there are some aspects of truth in ALL FOUR of these ideas - they are not necessarily mutually exclusive, although there are certainly proponents of each who will tell you in their books why THEIR particular explanation is the only one that is correct, and everyone else is wrong!