Question for evolutionists

[Trantor]

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and our genes keep on evolving, converging to their ultimate form..... and we'll just have to wait and see what that is, won't we?

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Careful, careful! Touch of the ID philosophy seems to be creeping in here!

[tolbiny]

not a bad summery, with the disagreement on Austalopithecus being the ealiest hominids as many recognize ardipithecus ramidus or ardipithecus kadabba as the ealiest know hominids with arguments being made for sahelanthropus being the oldest (quite contraversial). i have it on pretty good authority that a fuller description of Ar ramidus is coming out within the next year or two that will cement its status as bipedal (a nearly 40% complete skelton has been found).

Beyond the strict lineage a lot of times people want to know the why behind it so i thought i might toss out one of the more current theories.

7-8 million years ago (my) the ancestors of the great apes (chimps, gorillas, orangutangs and humans) were widespread throughout europe, asia and africa, they were some of the most prolific groups of mammels ever. At some point around 7 my the great apes began an extinction process that continues to this day, because of some change in geology, weather or predation (or any number of factors) infant mortality began to rise. Up unitil this point male great apes had little to no involvement in feeding/rearing their young. One group of the great apes (the hominids) began participating in their offsprings development and feeding which allowed for a higher percentage of thier own children to make it to a reproductive age- and hence could pass their genes along till the next generation. one of the major adaptations that allowed this was bipedalism, which freed the hominids hands for carrying food back to nursing and pregnant females. This bipedalism in males is also shown in females- and at this point hominids became the only striding bipedal animals on the planet. Walking upright allowed for another adaptation in females- that is the widening of the birth canal. Mammels brain to body ratio is limited by the size of the birth canal, for if the head is to large there will be complications in birth (it is true that humas have many more probliems in giving birth than any other mammel) as the head tries to pass. "Lucy"- the famous A aferensis stil had a primitive birth canal around 4 my. around 3 my the birth canal started to widen and become more oval and this has allowed for brain size to quadrupal from about 3my to around 300,000 years ago when humas hit a "wall" in brain size.

[Siegmund]

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converging to their ultimate form

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You had me until this.
There is no ultimate in evolution.

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If the amount of mass/energy in the universe is finite, there is most assuredly a limit beyond which more complicated structures can't evolve - every increase in local complexity has to be paid for by releasing heat or by increasing entropy somewhere else.

In the simpler case of using genetic algorithms to solve numerical optimization problems, you may allow the solutions to continue evolving forever, but the rate of improvement declines to nil as you approach the optimal solution. I think it's an open question whether arriving at a "perfect life form" or running out of energy will be the cause of evolution eventually grinding to a halt. I will leave that one to the philosophers.

[Rduke55]

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converging to their ultimate form

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You had me until this.
There is no ultimate in evolution.

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If the amount of mass/energy in the universe is finite, there is most assuredly a limit beyond which more complicated structures can't evolve - every increase in local complexity has to be paid for by releasing heat or by increasing entropy somewhere else.

In the simpler case of using genetic algorithms to solve numerical optimization problems, you may allow the solutions to continue evolving forever, but the rate of improvement declines to nil as you approach the optimal solution. I think it's an open question whether arriving at a "perfect life form" or running out of energy will be the cause of evolution eventually grinding to a halt. I will leave that one to the philosophers.

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There's a LOT wrong with this line of reasoning.
There's no room for talk of "improvement" towards the "ultimate" in evolution
More "complex" is not necessarily better
And it's not more "complicated" that I'm talking about - I'm talking about different.

Way too many quotation marks

[bearly]

one of my favorite professors used to jerk our chains by saying; 'yes, god created man thru the process of evolution.".............b

[benkahuna]

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But the selection of the phenotype isn't chance. that's the big difference.

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The genotype is more important as it is heritable. The phenotype does change in a on-random way in response to environmental conditions so you are correct that its selection is not based strictkly on chance, but that's not the most important point to make here.

[Siegmund]

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There's no room for talk of "improvement" towards the "ultimate" in evolution

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You can use different words if you prefer. A niche is a local maximum of a fitness function. A selection pressure is something which results in the fitter genes being passed on in preference to the less fit, and acts over time to move the species along the gradient of a fitness function. Speciation is possible near saddle points of a fitness function.

Do you find it strange that I use the word "improvement" (relative to whatever measure of fitness) to describe change in response to selection pressure?

I don't know how you can talk about evolution and NOT be talking about progress towards some theoetical optimum.

Some functions in some spaces (including all functions continuous on closed domains) have global maxima, and some others approach easily described singularities. Do you find it strange I want a name for the set of places a system can wind up if it is given infinitely long to optimize? (it doesn't have to be a unique limiting species, and, as I said before, we might never get there even if there is.)

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More "complex" is not necessarily better
And it's not more "complicated" that I'm talking about - I'm talking about different.


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This is true. But I started out talking about the idea of life as a self-organizing system, which has to pay the entropy piper in order to avoid its own degeneration, and the OP was talking about the development of rationality / self-awareness / ability to think - which I was equating with the idea of increasing information content in a species' collective minds and bodies.

[Rduke55]

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But the selection of the phenotype isn't chance. that's the big difference.

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The genotype is more important as it is heritable. The phenotype does change in a on-random way in response to environmental conditions so you are correct that its selection is not based strictkly on chance, but that's not the most important point to make here.

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Whoa! You can't say genotype is more important than phenotype. They're both equally important. Selection acts on the phenotype, the genotype is what is passed on.

And the phenotype dosn't change, the frequency of phenotypes change.

[Rduke55]

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There's no room for talk of "improvement" towards the "ultimate" in evolution

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You can use different words if you prefer. A niche is a local maximum of a fitness function. A selection pressure is something which results in the fitter genes being passed on in preference to the less fit, and acts over time to move the species along the gradient of a fitness function. Speciation is possible near saddle points of a fitness function.

Do you find it strange that I use the word "improvement" (relative to whatever measure of fitness) to describe change in response to selection pressure?

I don't know how you can talk about evolution and NOT be talking about progress towards some theoetical optimum.

Some functions in some spaces (including all functions continuous on closed domains) have global maxima, and some others approach easily described singularities. Do you find it strange I want a name for the set of places a system can wind up if it is given infinitely long to optimize? (it doesn't have to be a unique limiting species, and, as I said before, we might never get there even if there is.)

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More "complex" is not necessarily better
And it's not more "complicated" that I'm talking about - I'm talking about different.


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This is true. But I started out talking about the idea of life as a self-organizing system, which has to pay the entropy piper in order to avoid its own degeneration, and the OP was talking about the development of rationality / self-awareness / ability to think - which I was equating with the idea of increasing information content in a species' collective minds and bodies.

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I don't even know where to begin with this.
That is a seriously oversimplified view of speciation. What about genetric drift and speciation?

There is no theoretical optimum in evolution. Everything changes. Plus, evolution works with what it already has. We as humans (which some would - erroneously - consider as the peak of the evolutionary process) have a constellation of problems that other animals (including ancestral species) did not have.
If what you say is true, why have more recently evolved species went extinct while more ancient species still abound? Are we better evolved than say, the cockroach? Or bacteria? Or fungus? Based on the "working towards and optimum" theory, we are.
We are not. We all fit in a niche. And evolution, while looked at in the long term of millions, hundreds of millions, or even billions of years, actually can work on a much faster time-scale than that.
Nicehs are constantly appearing, disappearing, and changing. What might be good currently, may not be useful in the near future.

[benkahuna]

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Whoa! You can't say genotype is more important than phenotype. They're both equally important. Selection acts on the phenotype, the genotype is what is passed on.

And the phenotype dosn't change, the frequency of phenotypes change.

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I can and I do. Phenotype can change in the lifetime of an organism. The genotye is unlikely to change by more than a few bp (1X10^9/lifetime*2-3X10^9 bp for humans) in a lifetime. And the phenotype is only passed on through the genotype and only meaningful if expressed in future generations. If you don't understand the phenotypic difference in the same rabbit that has dark fur in one season and light fur in another season, you are missing something important. The frequency of genotypes change and it is what matters. You don't honestly believe any organism has the same phenotype throughout it's lifetime, do you? If you do, you're naive about genetics and gene expression. If you don't, you really have no choice but to concede my point.

Selection acts on phenotypes sure, but it may act on multiple phenotypes (almost certainly does) through the lifetime of an organism. Genotype is the common factor of all possible phenotypes of an organism. Due to the influence of environmental conditions in determining phenotype, I'd say genotype is what matters. Phenotype is merely a medium through which a genotype may establish its fitness within particular environmental conditions. Think about it. Logically, you know it's true.