Some questions on evolution

[vodkafan]

No. No I don't agree with that. Mostly because I provided two examples of things becoming less complex off the top of my head in the paragraph preceding the line you quoted.

Hi Esquilax, I don't accept losing teeth and toes and whales going back in the water as becoming less complex; they are just adaptations. The modern whale is probably more intelligent, has a better brain than the creature that was a proto-whale that lumbered about on land a few million years back. It has not got less complex. It has just adapted to the water and evolved.
We will probably have to agree to differ on that one, unless somebody else wants to jump in on one side or the other and shed some light.

[Chas]

No. No I don't agree with that. Mostly because I provided two examples of things becoming less complex off the top of my head in the paragraph preceding the line you quoted.

Hi Esquilax, I don't accept losing teeth and toes and whales going back in the water as becoming less complex; they are just adaptations. The modern whale is probably more intelligent, has a better brain than the creature that was a proto-whale that lumbered about on land a few million years back. It has not got less complex. It has just adapted to the water and evolved.
We will probably have to agree to differ on that one, unless somebody else wants to jump in on one side or the other and shed some light.

You have a weird definition of complexity, then. A species evolves becoming simpler, but that's not less complex?

You need to read a book on evolution by a real evolutionary biologist.

As far as a 'drive to complexity', the vast majority of life (in numbers and in total mass) on earth is single-celled. So, no drive.

[Anomalocaris]

Hi , I have only a layman's knowledge of evolution and have a few questions that nobody has ever been able to answer, hoping some knowledgable folks here might help me out.

1. I know that the exact mechanism of how life started is not yet known. What seems certain though is that it started surprisingly soon after the earth got created, life was just busting out all over. My question is this: obviously conditions must still be OK for life, otherwise we would be a dead planet. So why is new life not busting out spontaneously all over so we can see it happening?

There are two reasons.

1. Time scale - earth is 4.6 billion years old. If new life busts out somewhere on earth once every 1 million years, it would still have had done so 4600 times in the life of earth. But modern science is only 300 years old. The chance of it having happened once to be observed during the existence of modern science is 0.03%. The chance of it having happened where science happen to have been looking is much less still.

2. Opportunity - any life to just bust out is almost necessarily the least well adopted life that could possibly be called life. Any survivor from any previous busting out of life would have had a lot time to improve its adaptation to the environment. So one would expect once a single instance of life busting out have succeeded, its descendants would rapidly gain an insurmountable accumulation of evolutionarily advantages over any future life to come. So unless some environmental catastrophe were to be so complete as to wipe the slate completely clean, we would expect very few, possibly only one, instance of life busting out to leave any descendants. All subsequent instance would be overwhelmed and wiped out by the better adapted descendants of this one instance almost as soon as they arise.

2. It seems to me that there is a sort of drive towards more complexity. Why is this so? Or am I wrong? I mean, Viruses and Bacteria and Archea are successful ubiquitous organisms. What made them develop into more complex forms of more and more complexity, inventing sex and self awareness, intelligence along the way and all, until eventually we get to Mila Kunis?

I think that's enough to be going on with.

Uh, no.

1. The overwhelming majority of life on earth consists of simple one called organisms without cell nucleus. This has been the case since shortly after life we recognizes first arouse, and continue to be the case today. Whether you measure by the number of individuals, or by total biomass, the vast, overwhelming majority of life on earth has not gotten nearly as more complex as you might imagine. The dominant theme of life on earth, once we get away from our egotistical focus on what we can see through our naked eye, is one of conservatism. Only some plant and animal flotsam upon the vast ocean of conservatively simple bacterias have gotten steadily more complex.

2. In so far as life on earth have gotten more complex, complex often, but not always, pays in evolutionary competition. Complexity allows division of labor, and allows more focused, as well as more sophisticated, adaptation. As a result, complexity allows organisms to become better able to survive specific environmental stresses. So long as some complexity pays some times, some organism will steadily get more complex.

3. But complexity do not always pay, even for organisms that have gotten more complex in the past because complexity have paid in the past. As a result, there are numerous examples of formerly more complex organisms losing complexity. Take for example the sea squirt. So even for the complex flotsams floating upon a sea of simplicity, there is no steady progress towards greater complexity. Some become more complex, some stay conserved, some become less complex. So as a net result, Some did get more complex until, let there be Steven Hawkins or mila kunis. But many stays chimpanzees. Some, like the sea squirt, regressed back to bing Kirk Cameron's or Ken Ham.
So there is chance and opportunity allowing, but not drive towards, complexity.

[vodkafan]

Would you consider losing eyesight 'upwards to more complexity'?

Evolution sometimes leads to progress, but it sometimes leads in the opposite direction. For instance, the Texas blind salamander has lost his eyes after many generations of evolution due to the uselessness of eyes in the dark caves where he dwells.

http://sciencequestionswithchris.wordpre...d-species/

Aha! The plot thickens. Thanks Cato that's exactly the sort of contradiction I am looking for. That would certainly prove me wrong. Unless there is some other attribute that advances the organism instead. That is something I will look at. Thanks. Any more examples like that? Hang on just gonna go to the link....

[Angrboda]

I get what you are saying about single cells and the only way is up to more cells. But I want to play devil's advocate and keep asking why. We could have just mutated to a different single celled organism instead.

I think it may be more appropriate to say that life forms diversify, rather than that they become more complex. When they diversify, they evolve into all different levels of complexity, but a single celled level of complexity can't get any simpler, and so it forms a wall on one side of which is a range of complexity. Thus, from humans, if we evolve into different life forms, some will be simpler and some more complex. If you arrange all life forms as simple to complex, it will seem that things are getting more complex, but they're really only becoming more diverse.

[vodkafan]

Chuck, just read your reply thanks. I think your last 3 points conclusively shot down my argument. Thanks everybody for interesting and valuable answers. That one had been bugging me a long time.
Chas, I have read a couple of the Dawkins' books already that you mentioned and I still have The Selfish Gene on my shelf to read yet.

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rasetsu, thanks. I only just saw your post. I concede the point.

[Esquilax]

Hi Esquilax, I don't accept losing teeth and toes and whales going back in the water as becoming less complex; they are just adaptations. The modern whale is probably more intelligent, has a better brain than the creature that was a proto-whale that lumbered about on land a few million years back. It has not got less complex. It has just adapted to the water and evolved.
We will probably have to agree to differ on that one, unless somebody else wants to jump in on one side or the other and shed some light.

So what if the whale is smarter than its ancestor? Growing more complex in one area doesn't preclude growing simpler in another, and in the case of whales their legs evolved into flippers which are demonstrably simpler in terms of bone structure and design. Saying "oh, but it got more complex in this completely unrelated area!" doesn't change what I've said at all, and given that evolution isn't a ladder that goes all in one direction or all in the other, and that organisms don't have, like, some cohesive meta-intelligence governing how their bodies mutate, the metrics for each body part are always going to be changing independently of one another. What you seem to be looking for is a singular organism taking a step backwards in every respect at once, and I don't know why you would think that's even possible as evolution doesn't work that way.

See, this is the problem when you start off a conversation about complexity without ever defining what you think it is, or what you'd expect to see when an organism becomes more or less complex; you've begun in a vague and unfalsifiable place, and a less charitable part of me wants to say that now you're shifting the goalposts to retract your claim away from whatever rebuttals we bring to bear. I don't think that's what's happening, but it's damn close to it, unfortunately; you're leaving us groping in the dark about what you're actually discussing, it seems.

[vodkafan]

and I don't know why you would think that's even possible as evolution doesn't work that way.

See, this is the problem when you start off a conversation about complexity without ever defining what you think it is, or what you'd expect to see when an organism becomes more or less complex; you've begun in a vague and unfalsifiable place, and a less charitable part of me wants to say that now you're shifting the goalposts to retract your claim away from whatever rebuttals we bring to bear. I don't think that's what's happening, but it's damn close to it, unfortunately; you're leaving us groping in the dark about what you're actually discussing, it seems.

If my understanding is vague that's why I am asking the question in the first place! I am not trying to shift any goalposts and was only trying to get my question across. If we don't ask questions from people who may have more knowledge how do we learn?

[ThePinsir]

1) If an abiogenesis event were to occur today (and for all I know they may happen all the damn time), these new life forms would almost certainly, almost immediately, be eaten by bacteria and stuff.

2) The simple answer is "natural selection".