More fuel to the Psychoreligionology fire

[fishhook]

If evolution does not occur, how is it that we now have all different kinds of dairy cows, beef cattle, 100's of different breeds of dogs that didn't use to exist? When I was a kid there were only a few dozen kinds of tomato plants. Now there are are hundreds. There are all kinds of new colored roseflower bushes, etc,etc. How can new forms of life occur without evolution?

[AEKDBet]

C'mon everyone knows we can from the magic garden with the two naked people and the talking snake.


(paraphrased from David Cross)

[kalooki45]

Well, I'm no scientist, and can't tell you diddly about evolution. I can tell you about roses and dairy cows, tho [img]/images/graemlins/smile.gif[/img]

ALL roses come from the original "wild rose". This is a rambler/climber that grows naturally. It has 4 petals, I think, and is a cream color.
These strong root stocks are still part of your modern tea roses, etc.
The "fancy" part is grafted onto the strong root stock to produce the modern hybrids.They are all man-made--bred, cross-bred and developed for hundreds of years by man.

In the case of dairy cows, same story. They are part of selective breeding for characteristics--made over centuries, by man.

[fishhook]

Yes, man has guided the evolutionary process of these plants and animals in a particular direction to achieve certain desired results. Maybe that doesn't fit the actual definition of evolution, but it does demonstrate that mutations, if selectively propagated will result in new and different organisms. Isn't that what evolution does?

[kalooki45]

In the case of roses particularly, I wouldn't call it "evolution" at all. They still have to be grafted, you see. That's why your rose plants have that knob where the roots begin. Left to themselves, they'd be the same old wild rose as ever.
The cows also--I wouldn't mistake selective breeding for evolution. They are all cows still [img]/images/graemlins/smile.gif[/img]
Maurile's the expert here on the biology stuff--ask him how they define it--I can't say for certain.
It's my non-scientific guess that if you had to put a label on the cow herds--it would be "genetic engineering", not evolution.

[Bez]

Doesn't take a genius to see his maths is way off here. How the hell did he get so many qualifications?

[Bez]

The problem is that you've just plucked numbers out of the sky for the chance of a good or bad mosquito mating. I'd expect the difference to be much larger. A bad mutation would probably reduce the chances of mating substantially more than you are suggesting. You cannot prove something mathematically using made up numbers.

[Leroy Soesman]

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The problem is that you've just plucked numbers out of the sky for the chance of a good or bad mosquito mating. I'd expect the difference to be much larger . A bad mutation would probably reduce the chances of mating substantially more than you are suggesting. You cannot prove something mathematically using made up numbers.

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Do you see why you didn't understand a thing I said?

[maurile]

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i actually believe it works like this: imagine this:
we have a thousand mosquitos, 100 mosquitos have mutations, 900 don't. Off these 100, 99 have bad mutations making them less adapted, 1 has a good mutation, making him better adapted. A normal(non-mutated) mosquito has as 10% chance of getting throught the day, and then another 10% chance of producing offspring. Now let's say for a good mosquito these odds are 15 and 15 percent. For a bad mosquito 8 and 8 percent.

Now the most likely scenario is that the good mosquito dies without producing any offspring.

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Right. It will take some luck for the first mosquito with that beneficial mutation to successfully reproduce. There have of course been many instances of a good mutation being lost due to bad luck.

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This does not mean that immediately all mosquitos die.

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In your example, with the numbers you gave, they're getting wiped out pretty quickly.

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Probably some of the bad and some of the normal ones will survive producing large amounts of offspring. Therefore this mosquito family will not go extinct it will just "degenerate", they will become less adapted to their environment. Probably eventually in the very long run these mosquito will die out, but hey won't we all? And in the meanwhile their genes will become worse and worse instead of better, and they will be increasingly less adapted to the environment.

This is just to show how random mutations perse do not lead to better adaptation to the environment. It depends, as i wrote before, on how many of all mutations are good, bad and neutral, and how much the chance of producing offspring increases with a good mutation.

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Ah, I understand what you're saying now, and you are correct. If the mutation rate is too high, degeneration (and ultimately extinction) will occur -- except to the extent that some of the mutations lead to a lower mutation rate, which is quite possible. Mutation rate is variable like everything else, and is subject to the pressure of selection.

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Hypothetical? Not really. You can actually do experiments and see how many of the mutations are good and how many are bad.The more complex the organism becomes, the more likely it is that a random mutation is bad. Even more so in a complex environment, with a complex organism one small good mutation hardly improves the chances of survival of an organism.

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This is generally correct.

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In practice this turns out to the phenomenon of degeneracy of isolated populations like the nobelty in medieval times.

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No, that's completely different. That kind of degeneration isn't due to a mutation rate that's too high; it's due to the fact that recessive genes tend to be expressed more often when there's lots of inbreeding. (This doesn't always lead to reduced overall fitness in the population, but it does tend to at least temporarily increase the incidence of certain types of genetic diseases.)

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It is actually a quite serious problem for evolution theory.

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This is incorrect. Species that experience genetic degeneration because their mutation rate is too high will generally go extinct. This is not a problem. Lots of extinctions occur for all kinds of reasons -- and this is perfectly consistent with current evolutionary theory.

Your mosquitos who are nearly 99-1 underdogs to mate before dying aren't long for this world. But there are plenty of species out there with better odds than those.

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One solution might be mating. Through selection of the partners in the mating process it might be that even a small improvement of an organism dramatically increases its chances of mating. This would then make it a lot more likely for good genes to pass on than for bad ones. And that dramatic improvement is the crux of it all. Because the point is that if those chances don't improve dramatically, better adaptation to an environment is very improbable.

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A given adaptation doesn't have to improve anything dramatically. If its host has 1% more grandchildren than its fellow species-members who lack that adaptative trait, then the gene will spread through the population at the rate of a 1% increase every two generations. Every little bit counts.

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Summing up: it is not a simple problem, but a real one. One solution might be through the mating process, but this should be researched and it might be that more non-random rules are necessary for evolution to have a positive course (to make more and more adapted organisms throught the course of time).

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It actually is a very simple "problem," and has been researched up the wazoo. It's easy with computer simulations that can model what happens with different mutation rates, different ratios of good-bad mutations, etc.

[maurile]

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The cows also--I wouldn't mistake selective breeding for evolution. They are all cows still [img]/images/graemlins/smile.gif[/img]

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It's still evolution. "Evolution" denotes a change in allele frequencies in a given population over time.

Evolution works by mutation and selection. Most selection is "natural selection." But when humans are purposely exerting the selection pressure, it's "artifical selection." That distinction, however, is itself somewhat artificial.

Large tails are selected for in male peacocks because female peacocks find them attractive. This is natural selection. Large tails may be selected for in certain breeds of dog because humans find them attractive. This is artificial selection. They are both examples of evolution.

Cows are still cows, and dogs are still dogs, as kalooki45 pointed out. If you're looking for an example of new species being created by artificial selection, how about broccoli and cauliflower?