September 23 Blog Post

As a public school science teacher, I am always thinking of ways to teach the evolution of organisms without causing a disturbance...yet, I'm always thinking about the evolution of things. What amazes me about evolution is nothing is done frivolously. Things that aren't needed disappear. If only business worked in the same way...

Anyhow...thinking of the "spark" of life and how the molecules needed came about...I buy into the "negative mould" idea. Having to break down protein synthesis for freshman bio students I have come to appreciate the simplicity AND complexity of the process. In a "primordial soup" of inorganic chemicals (subjected to incredible amounts of lightning), I don't find it at all a stretch that self-replicating chains of certain molecules (that attract their opposite) would start to form.

It also doesn't surprise me that the more stable of the molecules would continue to exist, whereas the less stable wouldn't. Eventually those that created larger replicating groups became more and more complex, but the end goal was still to make more.

As energy was required for these bags 0f chemical reactions to continue on, small changes that led to the production of food from light or chemicals (photoautotrophs and chemoautotrophs) would have led to an increased stability. Items that required energy, but couldn't use light/chem to produce food brought in energy from the outside (heterotrophs). It has always been my understanding/belief that chloroplast and mitochondria may have begun as free-living, self replicating items (as indicated by the double membrane they posses and the mitochondrial DNA) that were integrated into anther cell and incorporated into the processes of the cell itself.

Selectional pressure seems likely to have played a role in creating similar acting/looking/behaving items based on convergent/divergent evolution. Reacting to similar environmental conditions would make many of these items similar to each other, even though they had different paths to get to a point (convergent)...and on the flip side, items that started to fill niches would break away from a group to avoid competition.

I think that Mayhew and Dawkins are pushing in the same direction on this. Mayhew looks at it from the standpoint of how organisms evolved and how they fit into their environment, and Dawkins does as well...but they differ in audience. I feel like Mayhew is working on my previous science knowledge and expanding it, but Dawkins is almost trying to CONVINCE me of something that he knows and is making a persuasive argument (look at the language). Dawkins is explaining how the engine works, but Mayhew is describing how the car fits into or society.

-Black 9/21/09 10:15 a.m.