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Author Topic:   What mutations are needed for a particular trait (e.g. wings) to arise?
skepticfaith
Member (Idle past 4043 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 1 of 111 (344820)
08-29-2006 5:45 PM


Is it possible mathematically?
How many random mutations would it have taken to create a bird and does this even seem remotely possible? Would it not take a series of random mutations (over time of course) - the odds of this happening being almost impossible?
What is the average mutation rate expected for a creature to evolve novel characteristics that are beneficial anyway?

What would be helpful would be a scenario - even a fictional one that could explain how a creature could evolve into a bird (not just with drawings of transitional types) but an explanation of the type of mutations that are needed.

Think about it like this - what are the all the possible errors due to mutation that could happen? And what is the likelihood that one of them will be beneficial? Has this been ever calculated mathematically?

The natural selection part seems to make sense but random mutation does not. Every SINGLE example of a beneficial random mutation e.g. resistance to black plague in Europeans seems too improbable to have occurred purely by chance.
Now - I cannot show that it is improbable but have the evolutionists have shown that random mutation ALONE IS responsible for these examples? Could they not be another unexplained force behind this?

Edited by skepticfaith, : Admin requested change..


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AdminWounded
Inactive Member


Message 2 of 111 (344831)
08-29-2006 6:05 PM
Reply to: Message 1 by skepticfaith
08-29-2006 5:45 PM


There are already about 3 different threads open on almost exactly this general topic.

It moight be better if you framed your OP more towards the thrust of the final section dealig with the specific character, and presumably result, of the neccessary mutations for a particular trait to arise.

Otherwise this doesn't seem clearly differentiated from the other ongoing mutatiom/macroevolution threads.

TTFN,

AW


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skepticfaith
Member (Idle past 4043 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 3 of 111 (344931)
08-30-2006 12:07 AM
Reply to: Message 2 by AdminWounded
08-29-2006 6:05 PM


How's this - better? I think this is a more unique for the forum now..

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AdminWounded
Inactive Member


Message 4 of 111 (344959)
08-30-2006 2:44 AM


Thread moved here from the Proposed New Topics forum.

  
PaulK
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Posts: 15578
Joined: 01-10-2003
Member Rating: 2.9


Message 5 of 111 (344964)
08-30-2006 3:15 AM
Reply to: Message 1 by skepticfaith
08-29-2006 5:45 PM


Re: Is it possible mathematically?
I don't know how to count the mutations required. It is significant that feathers and the lung structure seem to have been inherited by birds from their dinosaurian ancestors - which certainly increases the time available.

quote:

The natural selection part seems to make sense but random mutation does not. Every SINGLE example of a beneficial random mutation e.g. resistance to black plague in Europeans seems too improbable to have occurred purely by chance.

On a more general point, this is a very bad argument. Probability is not something that is easy to grasp when large numbers are involved, Simply guessing is not going to produce an answer that is worth anything.

Moreover, it is not enough to point out that specific beneficial mutations appear to be unlikely. If there are many possible beneficial mutations then the chance of getting A beneficial mutation will be much higher than the chance of getting any specific beneficial mutation. TO make an analogy the chance of winning the lottery is very low. The chance that someone will win the lottery is a lot higher. If you looked at the history of a large lottery and considered the probability of each of the actual winners winning you would come up with a very large number. But nobody would insist that there must be an "unexplained" force guiding the results.i


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ikabod
Member (Idle past 2814 days)
Posts: 365
From: UK
Joined: 03-13-2006


Message 6 of 111 (344968)
08-30-2006 3:32 AM
Reply to: Message 1 by skepticfaith
08-29-2006 5:45 PM


Re: Is it possible mathematically?
firstly you need to be clear where you start from .. feathers where around before birds , very light bone structure was a round before birds , modified forelimb structure was around before birds , the wishbone chest structure also may predate birds ...

and all of these features had being evoling over a vast time scale .

birds are a result of the accumilation of such features and suitible enviroment for favour such development .

to map the mutations that gave rise to each feature would firstly need a full mapping of the bird DNA , and given the current range of bird s where would you start ?

If you are looking for a step by step mutation map , you need to remember a mutation may occur ages before it becomes a seletcted trait within the population , it may sit dorment until a new enviromental pressure is applied .

as no one , as yet , a can travel back in time it is a lack of DNA samples from the vast timeline , that would make any mutation map difficult .

Note there are no errors due to mutation .. because there is no plan for mutation ... some will be leathal , all others only time will tell if they prove to be benifit or harm .
Further ther will be some mutations which may appear to have nothing to do with a line evoling into birds , but may have played a vital roll at a certain time point , ie desiease resistance to a plauge which cut down the compitition and opened up a space for the proto birds to exploite with low pressure .


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Hawks
Member (Idle past 4468 days)
Posts: 41
Joined: 08-20-2006


Message 7 of 111 (344970)
08-30-2006 3:40 AM
Reply to: Message 1 by skepticfaith
08-29-2006 5:45 PM


Re: Is it possible mathematically?
Now - I cannot show that it is improbable but have the evolutionists have shown that random mutation ALONE IS responsible for these examples? Could they not be another unexplained force behind this?

In science, there is ALWAYS room for new explanations. The falsifiability of scientific theories requires this. But for science to consider new explanations you have to (1) actually provide one and (2) provide evidence that your explanation is better than the mutation alone one.

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Archer Opteryx
Member (Idle past 1919 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 8 of 111 (344971)
08-30-2006 3:41 AM
Reply to: Message 1 by skepticfaith
08-29-2006 5:45 PM


feathers and flight
A good introduction to this question can be found here:
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_01.html
It outlines exactly the changes that would happen in the process of small dinosaurs growing feathers and taking to the air.

Mutations that elongate scales would tend to be passed on from one generation to the next because feathers would offer a survival advantage to small dinosaurs as insulation. They would also confer a reproductive advantage if female creatures, as experience suggests, were attracted to males with prominent feather displays. Mutations and natural selection working together would eventually ensure the placement of the longest (warmest) feathers at extremities, such as forearms, legs, and tail.

If the creature is mainly a ground runner, eventually the aerodynamic aspects of forearm feathers would come into play. The running creature with sufficiently large feathers on its forearms would find itself gliding for short distances when it ran at high speeeds. If this confers a survival and reproductive advantage, as it reasonably would, the genes for this emerging wing structure would be passed on and natural selection would shape the wing accordingly.

If the creature was a climber, the aerodynamic qualities of the feathered forearms would become apparent in leaping from trees. A similar situation to this one exists in flying squirrels of today: a mutation that gave them flaps of skin offered a survival advantage in cushioning falls and, eventually, gliding.

That's just a discussion of feathers. A few other helpful features as dinosaurs evolved into birds would be hollow bones. This was already a dinosaurian feature so nothing dramatic in the way of mutations would be required. A high metabolism, too, was already characteristic of this group of dinosaurs. Other mutations that would be necessary for the transition from dinosaurs into birds may be seen in the article above. Mutations that lead to the shaping of a wishbone and to wrist flexibility would be involved in effecting the transition or improving the flight abilities of a glider.

It's worth noting that all these mutations are effected through shifts in the shape of existing anatomical structures.

--

People often talk about 'the evolution of flight' as something synonymous with the evolution of birds or their feathers. It's worth remembering that insects became efficient flyers long before birds appeared. Among vertebrates, two other highly successful groups evolved the ability to fly: pterosaurs, a group that includes the largest animals ever to fly, and bats. These other groups took to the air by developing wings from membranes. Birds are the only group that requires feathers.

Edited by Archer Opterix, : Spelling.


Archer

All species are transitional.


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jar
Member
Posts: 31672
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.6


Message 9 of 111 (345022)
08-30-2006 11:09 AM
Reply to: Message 8 by Archer Opteryx
08-30-2006 3:41 AM


just a couple questions
Are there also not intermediate examples of flight such as fish that soar and snakes and squirrels and several non-flying insects?

Doesn't the fossil record also show many, many failures, critters that had feathers but never developed the next step or critters that developed true flight but still died out or critters that were kinda in the direction of modern birds but also died out, were a deadend?

Edited by jar, : -e+-


Aslan is not a Tame Lion

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Chiroptera
Member
Posts: 6814
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.2


Message 10 of 111 (345043)
08-30-2006 1:17 PM
Reply to: Message 1 by skepticfaith
08-29-2006 5:45 PM


Re: Is it possible mathematically?
quote:
Think about it like this - what are the all the possible errors due to mutation that could happen? And what is the likelihood that one of them will be beneficial? Has this been ever calculated mathematically?

Well, it is clear that birds did evolve from non-flying dinosaurs, that this evolution occurred over a large amount of time and over many, many generations, and that physical characteristics arise, largely, from the genetics of the individual. So it seems pretty clear that genetic mutations of some sort were responsible for the evolution of flight in birds.

We also know that random mutations do occur in the genomes in individuals, and that these mutations can be passed on to the next generation, and so random mutations would seem to be the best source for the mutations that led to flight. At least until someone finally comes up with a source of non-random mutations that may have occurred in the evolutionary history of birds.


"The fact that a believer is happier than a skeptic is no more to the point than the fact that a drunken man is happier than a sober one." -- George Bernard Shaw

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skepticfaith
Member (Idle past 4043 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 11 of 111 (345092)
08-30-2006 3:53 PM
Reply to: Message 5 by PaulK
08-30-2006 3:15 AM


Re: Is it possible mathematically?
quote:
On a more general point, this is a very bad argument.

How is this a bad argument? I am not the one proposing a new theory - has someone not asked this question?
Besides I am not saying that the chances of one beneficial mutation is impossible just an entire series of them to give rise to this trait.

quote:
TO make an analogy the chance of winning the lottery is very low. The chance that someone will win the lottery is a lot higher. If you looked at the history of a large lottery and considered the probability of each of the actual winners winning you would come up with a very large number.

Thus your analogy to the lottery is incorrect. The analogy is more like the same person winning the lottery 1000 or more times..This is why I want to KNOW approximately how much mutations is necessary ..A mathematical model could be build testing the probably of this even occurring...(the event being the evolution of the bird from a reptilian ancestor)..


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skepticfaith
Member (Idle past 4043 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 12 of 111 (345098)
08-30-2006 4:10 PM
Reply to: Message 8 by Archer Opteryx
08-30-2006 3:41 AM


Re: feathers and flight
quote:

A good introduction to this question can be found here:
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_01.html
It outlines exactly the changes that would happen in the process of small dinosaurs growing feathers and taking to the air.


Ok - that was an interesting read, but it does not cover what I am saying. How do we know this mutation is random - and how could a series of random mutations one after another (in a space of some generations - I guess) produce forelimbs and hands that became progressively longer then a host of other features eventually leading up to a bird.
Its like I can propose that it is more advantageous for a creature to have a longer tail and viola a mutation appears that gives this longer tail .. natural Selection ends up with more long tailed creature.. Now the creature needs to whip this tail for some reason (it would be advantageous in nature for some reason) and magically another mutation gives it a stronger more flexible tail ...Is this the way evolution works? Anything can just happen magically?

There is a design process in place here and random mutation does not seem to cut it ...


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dwise1
Member
Posts: 3847
Joined: 05-02-2006
Member Rating: 3.1


Message 13 of 111 (345102)
08-30-2006 4:16 PM
Reply to: Message 11 by skepticfaith
08-30-2006 3:53 PM


Re: Is it possible mathematically?
quote:
Thus your analogy to the lottery is incorrect. The analogy is more like the same person winning the lottery 1000 or more times..This is why I want to KNOW approximately how much mutations is necessary ..A mathematical model could be build testing the probably of this even occurring...(the event being the evolution of the bird from a reptilian ancestor)..

I disagree. As we understand the process, evolution does not work through individuals (which implies "within a single generation"), but rather through populations of individuals over several generations. So your analogy is highly incorrect, in that you have a single individual "winning" all the mutations. A mathematical model based on that analogy would not model the event in question.

A more accurate model would be a few individuals within the population winning the lottery, which their offspring then inherit as would then their offspring (also being the offspring of others who "married into the fortune" rather than having acquired it themselves). And some lottery-inheriting descendents would at some point also marry the descendents of another lottery-winner, combining those two lottery-inheriting qualities. Such that in time, a sizable portion of the population would consist of descendents of a lottery winner.


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skepticfaith
Member (Idle past 4043 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 14 of 111 (345105)
08-30-2006 4:38 PM
Reply to: Message 13 by dwise1
08-30-2006 4:16 PM


Re: Is it possible mathematically?
quote:
A more accurate model would be a few individuals within the population winning the lottery, which their offspring then inherit as would then their offspring (also being the offspring of others who "married into the fortune" rather than having acquired it themselves).

Of course of of these offspring would have to win the next lottery to aquire the next trait and so on and on. Still, the lottery is DESIGNED to produce a winner and so it is possible . For mutations to produce traits that are beneficial - the genetic code would have to be designed this way too. So the term random is not entirely accurate here - because in the lottery - we know all the possible outcomes for mutations we don't.
What I am getting at is that we can't talk about random when we don't even know what the realm of possibilities are. Clearly these 'series of random mutations' is a result of design which ensures that a few mutations would be beneficial and would give rise to useful traits.


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Gary
Inactive Member


Message 15 of 111 (345108)
08-30-2006 4:43 PM
Reply to: Message 12 by skepticfaith
08-30-2006 4:10 PM


Re: feathers and flight
You're right that random mutation alone doesn't cut it. That's where natural selection comes in. Natural selection works upon the random mutations to produce strings of beneficial mutations. You see, evolution works not on individuals, but on populations. If one member of a population gains a beneficial mutation, I'll call it A, over a few generations a large proportion of the population might have that mutation, especially if the mutation helped the first animal with the mutation have more successful offspring than its peers.

So then you have a population full of A-mutants. It's likely they'll continue to mutate as they reproduce, so if one animal out of the population has a second beneficial mutation, B, the population might end up full of animals with both A and B mutations. The AB-mutants continue like this, and eventually you have ABC-mutants. This process can repeat again and again, and the population can split up, and the environment can change, and before you know it the original population has split up into a bunch of groups that are all different from what their ancestors were like.

We get a distorted view of the probabilities of these events because the fossil record is limited by various factors, like the rarity of fossilization, while modern animals all look different because they are the tips of the branches on the evolutionary tree. We don't see too many of the dead ends deep in the evolutionary tree (though we've found a few, like pterosaurs) and we also fail to see that the way things are now is only one way, out of a practically infinite number of possibilities, that things could have turned out.


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