Darwin is my Copilot

The Origins of Text Deep Background 2: The Origin of Species

When you're playing the where has this strange anomoly (maybe) called Life come from? game, you get used to saying, well, let's just assume that Somehow...

So, uh, well, let's just assume that somehow, life has made it's appearance on the Earth stage. If you want to beleive that it was engineered by crazy metal salamanders swimming in the earth's molten core, that's okay by me.

So you have, well, organisms: they are unicellular, they have some minimal ability to respond to their environment in a directed fashion, they have membranes that allow the transport of elements that allow them to retain their organization, and excrete what's left over when they have utilized these elements. Most importantly, they have the ability to make copies of themselves. They spread and prosper, in a modest unicellular sort of way.

Flash forward just a whole bunch of millions of years: the surface of the planet is absolutely covvered with organisms. Number-wise, the majority are still unicellular. But in addition, well, you know the score. Ferns, flowers, mushrooms, insects, lizards, fish, sharks, octopi, whales, shrews, giraffes, the whole nine yards. What happened? Where did all these distinct, multicellular, specialized creatures that can breed and now make not copies, but variations on one another, come from?

Darwin said, survival of the fittest and thus natural selection. The creatures that survived and managed to make the most copies of themselves are better represented in the population. The creatures that don't cut it, can't reproduce or can't survive, fall by the wayside. Nature selects (although selection is a term containing a subtle value judgement) those best adapted (although adaptation is a term that contains a subtle value judgement) for survival. In a nutshell, what survives survives. Evolution for Dummies.

Well, wait, how does adaptation occur? Some argue that a creature (although, well, let's face it: creature is a term that contains a subtle value judgement) can adapt to its enviroment and pass this along to its offspring. The proto-giraffe stretches its neck out trying to reach long branches, and whad'ya know, it has long necked babies. Not so, says Darwin's camp. In their view, the adaptations are just variations, caused initially (in the assexual reproducers) by environmental mutagenic factors (who knows? they didn't know a hell of a lot about the thermodynamic basis of reproduction back then). The mutations that have a survival edge survive. Selection selection selection. Unicellular breeds multicellular, groups of cells start to specialize. Once breeding enters the picture, (another big mystery), there's a new element. Now creatures can induce their own mutations, as it were: every generation is a survival experiment. The breeders specialize to the point that their germ cells (eggs and sperm, yahoo) are incompatible outside their own group. You got yourself a species. A conglomeration of specialized cells acting as a singular organism, descended from untold eons of whatever works, taking advantage of "chance" mutations. Hence this modern world.

klik if you demand tedious explanations of every little thing.