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27 Jan 2015, 7:40 am

Several have had a stab at this topic within other thread topics.
So I thought it would be good to start an evolution topic all of its own.

The arguments for and against Evolution often involve 3 basic facets:

1. Spontaneous origin
2. Complexity vs Entropy
3. Biological choice and expression

I'll make a small start. I'm not quoting any of the books or sites I've read. Just putting it in my own words.

1. Spontaneous origin has been proven to be possible, especially in the different conditions of some 4 billion years ago. Some suggest that those very conditions would also wipe out the first amino acids. Yet over a period of a billion years or so, the possibility of some surviving increases substantially.

As for those amino acids evolving in complexity, the same thing applies. Capillary action, hexagonal shaping, ice crystal formations and so forth are ways in which molecules naturally form patterns in reaction to the environment, many of which are so random as to be almost unrepeatable. In a similar way, I see the first biological "substances" randomly forming patterns. And once again, over a billion years, many will survive - enough to be available for the next forming event.

The trouble we have in comprehending "likelihood" is in isolating our thinking to just this planet. But if you imagine the same randomness occurring over billions of years, throughout this galaxy's billions of possible planets, and throughout this universe's billions of possible galaxies, then it becomes not a question of if, but when. This planet was just one of the lucky ones.

2. Complexity in the face of entropy. I'm not going to quote thermodynamics law. I prefer to look at things, when applicable, in a more intuitive way. We all know that if you put a brand new car in a field, and give it enough time, it will not evolve into the next model. It will instead rust, fall apart and eventually rejoin the natural elements. We also know that there is no such thing as a perpetual motion machine. And we know that every moving body, subject to friction, will come to rest. Everything in this universe seems to be on a downhill ride.

But the available energy is what allows us to drive uphill, metaphorically and actually. We still have more than enough energy, in the ground, in the sun, in the rivers and oceans, to use it to create. Plants use it to evolve from a tiny seed to a hundred foot pine. Nature uses it in abundant ways, to create. And humans use it in creative ways to advance.

Complexity is a part of that uphill ride. Elements use that uphill energy and the natural devices (like crystallization and capillary action) to randomly produce new molecular structures over millions and billions of years.

3. Biological choice and expression. One of the worst aspects of evolution discussion is they way it is described in documentaries, which gives the impression that evolution is choosing to upgrade the organism to suit its surroundings. I think I heard David Attenborough explain it once, but I still find the practice difficult to justify. In evolution, change is random and choice is through environment and competition. And most species failed to survive, once conditions changed.

The Galapagos Islands have several examples of creatures which adapted to a different environment, but that adaption wasn't on purpose. Many other creatures would have failed to adapt, yet neither those who survived nor those who failed to survive had a choice in the matter.

I expects small creatures may be more likely to show evolutionary changes faster than large creatures, for the simple reason that they have more generations in a given period. In a thousand years humans will produce maybe 40 generations, while birds will produce a thousand generations. So, over a few thousand years you're more likely to see evolutionary change in a bird than in a human. And so it was with a species of bird on the Galapagos Islands. I forget its name, but the only difference between it and its land-bound cousin is bigger webbed feet, an advantage that probably saw it out-compete another species.


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Jono
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27 Jan 2015, 8:45 am

I'll address each of your 3 points.

1. I think that what you're describing here is abiogenesis, the process out which non-life became the first life. First of all, the title "spontaneous origin" is not accurate because the actual process of abiogenesis, according to current theories, is anything but spontaneous and actually takes place over a period of billions of years. It's a slow process from amino acids forming from basic chemicals up to the first lipid proteins forming around the complex rna/dna molecules that protect them creating the first proto-cells. Secondly, abiogenesis is not actually part of the theory of evolution, you don't need to know how life originated in order to know how it evolves and diversifies.

2. The second law of thermodynamics, the law of increasing entropy, only applies in closed systems. Life is not a closed system because it absorbs energy as well as expels it. So, if you look at life and how entropy appears to be decreasing, the second law of thermodynamics is not actually violated because life is an open system and if you include the outside energy sources to construct a closed system, you'll find that the entropy is still increasing overall.

3. Evolution doesn't "choose" to upgrade the organism to suit it's surroundings. Rather, you've multiple mutations that initially appear randomly but the surroundings kill off the mutations that are maladaptive simply because the organism would not be able to survive in them.



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27 Jan 2015, 9:21 am

Besides, the Second Law of Thermodynamics applied only to thermal energy, not genetics.


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