Randomness in Evolution: Valid and Invalid Usage

[sol invictus]

I would disagree, the describe how a system works in an idealised manner with some simplifications. They are abstractions.

Yes - and those idealizations are "impossible" in exactly the same way they are for evolutionary predictions. Again, science always works like that.

Useful theories help make useful predictions.

Tautology.

I am stating that theory can account for the case in reality that evolution of traits is not inevitable, but there would be different likelihoods of occurrence for different traits

Sure - the theory can in principle handle any situation. It's just a question of our ability to work out what its predictions are.

Infinite time, infinite populations or infinite resources are (nearly) worthless simplifications when discussing evolutionary systems.

Certainly not "worthless" - that's obvious nonsense. Just look at the history of the field, or at the history of science in general.

But anyway you should be arguing with mijo, not me - he's the one that keeps quoting things like those classical papers of Kimura, which always assume things like infinite time and infinite resources.

 

[jimbob]

But, I would be in the camp that would say intelligence would have likely evolved on Earth, even if the KT event never took place, though it might not be in the same form. It might not be hominids, nor even mammals for that matter. But, whichever life form manages to acquire it first, would probably dominate the place.

Now this is actually the nub of the discussion within evolutionary biology.

Whether the course of evolution is mostly predetermined with random effects limited to only unimportant differences, or whether the complex interactions mean that although adaptations will occur, what form they will take is not predetermined. If you keep rerunning the tape of evolution, will you get results that only differ in inconsequential ways?

 

[Wowbagger]

If you keep rerunning the tape of evolution, will you get results that only differ in inconsequential ways?

It depends on what level you are looking at, and how you define "inconsequential".

Evolution makes it clear, to me, that small difference will magnify over time - but even with that, there would still be convergence on the broader behaviors of life forms.

You would get plants and animals that behave in recognizable ways, even filling recognizable niches with recognizable innovations. But, would look very different. You might get sentient "lizard"-like-things instead of sentient "mammals", for example, but those "lizards" would probably have stages of civilization somewhat similar to our own, and they would probably "dominate" the planet to a similar degree that we have.

But, it won't be a perfect match. We might actually be able to predict how they would differ. For example, let us assume these "lizards" are cold blooded.

The advantage of warm-bloodedness, is that you can carry more of the environmental factors needed to sustain life, with you, wherever you go. But, you still need protection against extreme conditions.

Cold-blooded creatures have it worse. They cannot regulate their body temperature, so they would have more need to protect their bodies against more types of conditions.

We can predict that, if cold-blooded entities gained sentience, they would probably develop clothing and shelter at an earlier stage than mammals, and it would be an even deeper core instinct in their society. They would be so good at protecting themselves, at such an early stage, that they might even perfect scuba gear and spacesuits in less time than we did. (Measured from when intelligence first takes off.)

We can also predict that it might take a little longer for the "lizards" to acquire intelligence, than Earth mammals, in the first place; because mammalian warm-bloodedness allows them to examine more of the planet sooner, thus there would be a little more pressure to be innovative and develop an intelligence.

Does that answer the question?