Evolution is not random -here's why

[Cooky]

So Landon, look closely at the pics you posted. One thing that should stand out to you is how different taxa achieve flight via very diverse means. With the flying squirrel it's a flap of skin between limbs. But with birds it's via hollow bones, feathers, and modified forelimbs. Then with insects its via outgrowths of the exoskeleton.

If all those traits were pre-planned and executed by non-random mutations, why did it occur via such diverse means? It would seem to me that such diversity supports all of it originating via random mutations working on pre-existing anatomies.

So is it impossible that animals had ancient genes from their common finned ancestors, and those genes merely refreshed? If that makes any sense.. Do you know what I mean?

 

[beenherebeforeagain]

But the mutations didn't occur overnight. It would have taken a millions of years for the flying squirrel to have had flappy, unflyable skin turn into something useful.

No, the changes did not happen "overnight." I don't think there's anyone arguing that such a change would happen in a short period of time. It's doubtful that any squirrels were running around with lots of "flappy, unflyable skin." A sequence that makes sense would be that a few of the critters in a population had a little more skin on their sides than the rest of the population. Over time, those with the extra skin were able to jump farther and therefore more easily avoid predators and/or find more food and mates. More skin between the fore and hind legs led to better and longer gliding flights...those lacking this adaptation would have to run down trees, cross the ground, and run back up...a lot of expenditure of energy and exposure to predators that those with wingflaps aren't exposed to. Eventually, those with the wingflaps become a separate species from those without the extra skin.

Any of them that had a whole bunch of extra flappy skin would be less likely to be able to glide or climb well, and would also be selected against by predation and energy expended to move about.

...Same with all the rest who forfeited their front limbs. And for feathers to have coincidentally developed, I can only imagine wings would have only been advantageous for slapping prey around. But even that does not seem advantageous.

Thinking of an evolutionary change as a "forfeit" of something is not correct. What happens is that in a population, some individuals develop minor differences that give them some minor edge. If the ancestors of birds 'forfeited' their front legs, it was because what they gained by having front appendages devoted to flight gave them an advantage over those in the population that didn't have those.

Again, incrementally, the differences would have developed. Starting with a population of a species that had developed feathers (which are modified scales of skin), some were better able to survive and reproduce because those feathers helped in some way...avoiding predators, spending less energy finding food, appealing to members of the opposite sex, or so on...those whose feathers didn't help them in relation to these selection pressures either died out, or evolved towards other evolutionary solutions...that is, would eventually become a different species.

Frankly, if all you can imagine is a wing for slapping prey around, then I think that you aren't trying very hard. And even a slight advantage in being able to capture prey by slapping them around, or to avoid predators, or to attract mates (My! What pretty wings you have, my dear!) would be enough to make such a trait widespread in a population in just a few generations.

Just as with the flying squirrel, just a small advantage by being able to glide farther or longer or with more control than other members of the population would be enough to successfully adapt to the pressures (predation, mate appeal, etc.) to reproduce and survive as a population.

 

[It Aint Necessarily So]

Evolution is not random - here's why

Evolution is not random because natural selection is not random.

"Natural selection is an anti-chance process, which gradually builds up complexity, step by tiny step. The end product of this ratcheting process is an eye, or a heart, or a brain - a device whose improbable complexity is utterly baffling until you spot the gentle ramp that leads up to it. " - Dawkins

I developed flight totally independently. Just the mention of Brussels sprouts.

Agreed. Vile weed.

 

[Cooky]

Would wings or "soaring" have developed more readily due to ancient DNA from our marine ancestors?

 

[Father Heathen]

"I'm incapable of understanding something, therefore that something is impossible. Reality itself is restricted by the limitations of my intellect."

 

[Cooky]

"I'm incapable of understanding something, therefore that something is impossible. Reality itself is restricted by the limitations of my intellect."

The law of probability suggests otherwise. Six different species? All unrelated develop the same mutations. Yes, I understand that natural selection can thrust this mutation forward due to advantages... But the mutation itself had to occur first. Do you not see the unlikeliness of this?

 

[Cooky]

No, the changes did not happen "overnight." I don't think there's anyone arguing that such a change would happen in a short period of time. It's doubtful that any squirrels were running around with lots of "flappy, unflyable skin." A sequence that makes sense would be that a few of the critters in a population had a little more skin on their sides than the rest of the population. Over time, those with the extra skin were able to jump farther and therefore more easily avoid predators and/or find more food and mates. More skin between the fore and hind legs led to better and longer gliding flights...those lacking this adaptation would have to run down trees, cross the ground, and run back up...a lot of expenditure of energy and exposure to predators that those with wingflaps aren't exposed to. Eventually, those with the wingflaps become a separate species from those without the extra skin.

Any of them that had a whole bunch of extra flappy skin would be less likely to be able to glide or climb well, and would also be selected against by predation and energy expended to move about.


Thinking of an evolutionary change as a "forfeit" of something is not correct. What happens is that in a population, some individuals develop minor differences that give them some minor edge. If the ancestors of birds 'forfeited' their front legs, it was because what they gained by having front appendages devoted to flight gave them an advantage over those in the population that didn't have those.

Again, incrementally, the differences would have developed. Starting with a population of a species that had developed feathers (which are modified scales of skin), some were better able to survive and reproduce because those feathers helped in some way...avoiding predators, spending less energy finding food, appealing to members of the opposite sex, or so on...those whose feathers didn't help them in relation to these selection pressures either died out, or evolved towards other evolutionary solutions...that is, would eventually become a different species.

Frankly, if all you can imagine is a wing for slapping prey around, then I think that you aren't trying very hard. And even a slight advantage in being able to capture prey by slapping them around, or to avoid predators, or to attract mates (My! What pretty wings you have, my dear!) would be enough to make such a trait widespread in a population in just a few generations.

Just as with the flying squirrel, just a small advantage by being able to glide farther or longer or with more control than other members of the population would be enough to successfully adapt to the pressures (predation, mate appeal, etc.) to reproduce and survive as a population.

Regardless, there would have been at least a thousand year period where the slightly flappy skin, or the pre-webbed feet, or the function-less wings would not have had a single advantage in flight. That period would have existed. Even if it were a short period in terms of evolution, it would still have been a substantial number of years.

 

[beenherebeforeagain]

The law of probability suggests otherwise. 6 different species? All unrelated develop the same mutations. Yes, I understand that natural selection can thrust this mutation forward due to advantages... But the mutation itself had to occur first. Do you not see the unlikeliness of this?

"flight" is not a mutation. Each one of the examples you posted, and you can read about at wikipedia, etc., came up with very different solutions to the problem of survival through the use of flight. The mutations having to do with a flap of skin between the fore and hind legs of a mammal have nothing to do with mutations having to do with the development of wings in insects, neither of which have anything to do with the mutations that gave the rays their structure or function, and those had nothing to do with the development of a keel, feathers and hollow bones that show up in birds.

 

[beenherebeforeagain]

Regardless, there would have been at least a thousand year period where the slightly flappy skin, or the pre-webbed feet, or the function-less wings would not have had a single advantage in flight. That period would have existed.

no, you misunderstand--no fully developed wing in a bird-ancestor would have occurred. No fully developed skin flap in a squirrel would have developed unless there were ancestors with less-developed skin flaps that gave them a slight advantage. A slight skin flap is immediately an advantage if it allows the current individual to escape predators, find food more easily, or find mates more easily. If it doesn't provide an immediate advantage, then the trait is unlikely to grow, as larger skin flaps are likely to be in the way...

There is no time when an individual or an entire population is living with fully developed wings, and then one day one of them says, "Oh, look what I can do guys! I can flap my wings and fly!"

The only way a fully developed wing develops is if there are lots of incremental steps from having feathers of the forelimbs.

The first wingflap was after a whole lot of generations of proto-birds gliding...and it may have been many generations before any proto-bird did more than flap occassionally...

 

[Jose Fly]

So is it impossible that animals had ancient genes from their common finned ancestors, and those genes merely refreshed? If that makes any sense.. Do you know what I mean?

Not sure. Do you mean the genes lay dormant until they were needed for flight?

 

[Cooky]

"flight" is not a mutation. Each one of the examples you posted, and you can read about at wikipedia, etc., came up with very different solutions to the problem of survival through the use of flight. The mutations having to do with a flap of skin between the fore and hind legs of a mammal have nothing to do with mutations having to do with the development of wings in insects, neither of which have anything to do with the mutations that gave the rays their structure or function, and those had nothing to do with the development of a keel, feathers and hollow bones that show up in birds.

I see. So categorizing animals as those who possess "flight" is actually an abstract thought. In actuality, they are completely different processes?

 

[Cooky]

Not sure. Do you mean the genes lay dormant until they were needed for flight?

Yes.

At one point, all life soared. Perhaps that explains why soaring or flying is a common mutation?

 

[Jose Fly]

Six different species? All unrelated develop the same mutations.

Except they're not the same mutations. That was my point when I noted the different means of achieving flight in different taxa.

 

[Jose Fly]

Yes.

At one point, all life soared.

Then no, that's not a plausible scenario. Dormant genes accumulate mutations and since they're not active, there's no selective pressure to keep them functional.

 

[Cooky]

Except they're not the same mutations. That was my point when I noted the different means of achieving flight in different taxa.

Yes, but the results are the same. But that could be my abstract thinking with its tendency to categorize.

 

[Jose Fly]

Yes, but the results are the same.

No they're not. The anatomies of birds and insects are wildly different.

 

[beenherebeforeagain]

how unlikely is it? Given there were (and are) billions upon billions of individuals for millions and millions of years, all subject to the pressure of predation, the pressure of needing to find enough food, the need to find and successfully mate and have offspring that survive to reproduce under the same pressures in a mostly slowly changing environment...

If the odds (and I have no idea what the proper figures would be) are a million to one against, and there are 10 million proto-birds, then the odds are 10 to 1 that the mutation will actually happen.

And since ability to fly is the incremental development of a number of different mutations, that ability becomes more likely with each passing generation, where some even minor advantage by one of the tiny incremental mutations and the eventual interaction of those mutations.

A million individuals per generation in a million generations over millions of years provides trillion combinations of genes and mutations. One in a million? that's a million chances for the evolution to work all those changes...

 

[Cooky]

No they're not. The anatomies of birds and insects are wildly different.

It could be I've classified them based on the results of their mutations, when the mutations themselves are quite different. That would be a human tendency.

 

[beenherebeforeagain]

I see. So categorizing animals as those who possess "flight" is actually an abstract thought. In actuality, they are completely different processes?

Flight is a capability. As is swimming, burrowing, crawling, jumping, running...

There are lots of ways that different living things achieve each of these, some of them are capable of doing more than one of these. The exact way each lineage does it depends on those who came before in their lineage.

The "flight" of rays and penguins in the medium of water are very different, and the histories and anatomies are very different...yet in trying to survive, both lines came up with something that "looks like" flight in the medium of water.

Likewise, insects, two varieties of mammals, a variety of reptile, and a variety of proto-dinosaur came up with motion through the medium of air that we call flight. And there are a number of others who float, balloon or glide in the air, too...

 

[Valjean]

I believe it's called "convergent evolution". I find it extremely bazaar and highly unlikely. So unlikely, that it is impossible. It should be clear that mutations are not random, but are based on environmental needs. Somehow.

You don't understand the process. The mutations are random. Which mutations are kept is not. The useful ones increase in frequency in the population. The useless ones are weeded out.

Yes, there is a definition for it, however doesn't it suggest that mutations are based on environmental needs or allowances? And are not ultimately "random"?

NO! That's not how natural selection works. The mutations are random. Which ones get selected for propagation and which are removed from the population is not.

But the mutations didn't occur overnight. It would have taken a millions of years for the flying squirrel to have had flappy, unflyable skin turn into something useful.

Mutations occur all the time, as does sexual mixing of genes from two parents. Not all puppies in a litter are identical. But for a useful feature, from mutation or recombination, to spread through a population takes many generations.