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Author Topic:   What mutations are needed for a particular trait (e.g. wings) to arise?
skepticfaith
Member (Idle past 4063 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 46 of 111 (345510)
08-31-2006 5:50 PM
Reply to: Message 44 by Belfry
08-31-2006 5:43 PM


Re: Summary ..
quote:
What makes you so "sure" there wouldn't be such fossils, skepticfaith?

Because I have not seen any ..

care to show me a few links ?


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PaulK
Member
Posts: 15646
Joined: 01-10-2003
Member Rating: 2.8


Message 47 of 111 (345512)
08-31-2006 6:05 PM
Reply to: Message 39 by skepticfaith
08-31-2006 4:01 PM


Re: Summary ..
quote:

Now the chances of the first trait happening (whatever that was) is equivalent to winning the lottery...

This is over-literal, in that you are taking an illustrative example as providing figures that are directly relevant which is incorrect. In fact it is more likely that there are several beneficial mutations which could start the development of wings, and it should be added that there are a huge number of individuals where the first mutation could have occurred. So the probability might be much higher than the chance of winning the lottery with a single ticket.

quote:

Mutations happen at a certain rate (I guess this is quite high) for each creature. Most of the mutations are neutral and do not affect the population or creature substantially. Many of them are detrimental and the creature dies from disease.

While detrimental mutations are more frequent than beneficial mutations it is not the case that all or even most cause the recipient to "die from disease". By definition any mutation that makes the recipient less likely to successfully produce offspring is detrimental - how this occurs is not part of the definition.

quote:

So far the odds are not like the same person winning the lottery the same time (as I previously stated) because of the numerous failures (diseases, harmful, neutral mutations etc) over many,many generations, and also numerous sub-branches which were semi-successful at least.


This at least is mostly right although it should be added that there are even other beneficial mutations involved. If we only looked at beneficial mutations we would see that those related to wing development are only part of the story.

r


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skepticfaith
Member (Idle past 4063 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 48 of 111 (345514)
08-31-2006 6:18 PM
Reply to: Message 47 by PaulK
08-31-2006 6:05 PM


Re: Summary ..
quote:
In fact it is more likely that there are several beneficial mutations which could start the development of wings, and it should be added that there are a huge number of individuals where the first mutation could have occurred.

What do mean by this? The first mutation happened in one individual first, didn't it? Are you saying that the exact same mutation happened in more than one individual the first time? From what I understood the first individual with first mutation passed its genes down from generation to generation until it became more prevalent in the population.

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crashfrog
Inactive Member


Message 49 of 111 (345516)
08-31-2006 6:48 PM
Reply to: Message 46 by skepticfaith
08-31-2006 5:50 PM


Re: Summary ..
care to show me a few links ?

Well, allow me to "link" you to the paleontology and entomology departments of your local major university. They'll almost certainly have a museum of fossils that you can view by arrangement.

Also, a Google Image search for "fossil insect" returned more than 2600 results.


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NosyNed
Member
Posts: 8868
From: Canada
Joined: 04-04-2003
Member Rating: 7.2


Message 50 of 111 (345518)
08-31-2006 7:04 PM
Reply to: Message 49 by crashfrog
08-31-2006 6:48 PM


insect rarity
From the first site that popped up on that google:

quote:
Unlike the trilobite that has left a prodigious fossil record, the preservation of insects in sedimentary matrix is relatively rare, and essentially limited to the Laggerstat sites. The reason for the scarcity of insect fossil is the poor preservation potential of the insect's exoskeleton.

In addition,I believe the first request was for the evolution of flight in insects which would be as SF guessed very hard to catch in a set of fossils that are scarce to begin with.


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NosyNed
Member
Posts: 8868
From: Canada
Joined: 04-04-2003
Member Rating: 7.2


Message 51 of 111 (345523)
08-31-2006 7:23 PM
Reply to: Message 49 by crashfrog
08-31-2006 6:48 PM


Some insect evolution of flight info
Insect flight evolved about 330 million years ago. There is genetic evidence that wings evolved from articulated gill plates on the limbs of aquatic ancestors, rather than being novel outgrowths from the body wall (Carroll, Weatherbee, and Langeland, 1995; Averof and Cohen, 1997

From: http://www.nurseminerva.co.uk/adapt/evolutio.htm

and from this site: http://www.sciam.com/article.cfm?articleID=0007973F-A85D-102A-A85D83414B7F0103

We see that indeed the evolution of insect flight is NOT well documented in the fossil record as one would expect.

quote:
The oldest known evidence of winged insects�that is, complete fossilized bodies with fully formed wings attached--dates to around 330 million years ago. But because there is a diversity of species capable of powered flight from this time period, insects clearly evolved wings well before that time. "This chert provides a tantalizing scrap of evidence to suggest that we�re missing a huge amount," Grimaldi remarks, "and there�s probably this wonderful progression of insects with protowings yet to be discovered." --Sarah Graham

from: http://www-geology.ucdavis.edu/~cowen/HistoryofLife/CH13.html

quote:
A new cladistic analysis of living stoneflies, based on molecular evidence as well as wing structure and flight style, shows that the most "basal" of living stoneflies are surface skimmers. This suggests, though it can't prove, the stonefly flight began with skimming. The implication, of course, is that the same might apply to all insect flight. Reference: Thomas, M. A., et al. 2000. Molecular phylogenetic analysis of evolutionary trends in stonefly wing structure and locomotor behavior. Proceedings of the National Academy of Sciences, published online before print November 14, 2000.

That site also has a link to videos of skimming stoneflies. I am often surprised by the number of cases where we have living forms which are so very "transitional" in nature.


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crashfrog
Inactive Member


Message 52 of 111 (345526)
08-31-2006 7:44 PM
Reply to: Message 50 by NosyNed
08-31-2006 7:04 PM


Re: insect rarity
Well, even my wife, who is smarter than me in every regard, has been known to be wrong. (This is not a position that I promote in her presence, of course.)

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Belfry
Member (Idle past 3426 days)
Posts: 177
From: Ocala, FL
Joined: 11-05-2005


Message 53 of 111 (345533)
08-31-2006 7:51 PM
Reply to: Message 50 by NosyNed
08-31-2006 7:04 PM


Re: insect rarity
Nosy writes:

In addition,I believe the first request was for the evolution of flight in insects which would be as SF guessed very hard to catch in a set of fossils that are scarce to begin with.


Well, SF said, "I am sure there are absoultely no fossils that could even suggest insect evolution." I took that at face value, but perhaps you're right about what SF meant. Certainly there isn't a perfect fossil record for insects (nor would we expect it), but fossils are there, and what we have found does support the nested heirarchy, and it lines up well with genetic evidence, etc.

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NosyNed
Member
Posts: 8868
From: Canada
Joined: 04-04-2003
Member Rating: 7.2


Message 54 of 111 (345538)
08-31-2006 8:12 PM
Reply to: Message 52 by crashfrog
08-31-2006 7:44 PM


being wrong
Even mine too. She wasn't very good at accepting that she was wrong because she got so very little practice at it.

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nator
Member (Idle past 511 days)
Posts: 12961
From: Ann Arbor
Joined: 12-09-2001


Message 55 of 111 (345547)
08-31-2006 8:47 PM
Reply to: Message 36 by skepticfaith
08-31-2006 2:52 PM


Re: Finite possibilities - not infinite..
quote:
I see your point about selection but what you mention is not a mutation! There were alredy slightly darker critters in the population!

No kidding there were already slightly darker creatures in the population.

If there weren't any creatures with dark enough fur, then the predator would eat them all and they would go extinct.

You seem to be under the mistaken impression that a population has to "wait" for a mutation to confer an advantage.

In actuality, it is mutations that confer slight variations within the individuals of a population that are selected or not by the environment.

IOW, they already exist within the population.

If the population had to wait for a mutation, they'd likely be SOL and go extinct if the environment changed too rapidly.

(And we do see that 99% of all life that has ever existed has, indeed, gone extinct.)

Let's pretend that we have some kind of awful, crazy government that decided to exterminate all of the people with blue eyes.

Having any eye color but blue is determined by your genes, and suddenly, having non-blue eyes suddenly has become very beneficial, even though it was pre-existing in the population.


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nator
Member (Idle past 511 days)
Posts: 12961
From: Ann Arbor
Joined: 12-09-2001


Message 56 of 111 (345551)
08-31-2006 9:00 PM
Reply to: Message 54 by NosyNed
08-31-2006 8:12 PM


Re: being wrong
quote:
She wasn't very good at accepting that she was wrong because she got so very little practice at it.

Maybe that's my problem?

;)


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 Message 54 by NosyNed, posted 08-31-2006 8:12 PM NosyNed has not yet responded

  
Archer Opteryx
Member (Idle past 1938 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 57 of 111 (345562)
08-31-2006 9:32 PM
Reply to: Message 45 by skepticfaith
08-31-2006 5:48 PM


Re: Summary ..
skepticfaith:

Each novel trait arose because of a mutation and this beneficial trait - the chances of that appearing is the odds of winning a lottery.

What 'novel traits' are you talking about? What definition of 'novel trait' are you using?

Feathers are elongated scales. Are they 'novel'?

This is not after the fact - it is before.

So to discuss feathers we have to discuss the origin of scales...?

This takes us way out of the realm of dinosaur-bird evolution. Now we're going back to fish.

It might help if you told us what traits you regard as 'novel' so we can discuss what would have to happen. Wishbone? Keeled sternum? The Velociraptor wrist feature? What?

If you disagree with this then what are the chances of a beneficial mutation that introduces a novel trait?

I'll leave chances to the geneticists and Vegas oddsmakers. In a vacuum--you don't say what a 'novel trait' is--I don't see how anyone can say.

And as I said, the 'chances' are not a very important issue anyhow.

What are the odds of you being here? Well, we'd have to calculate the odds of two people, with exactly the right genetic structure out of all the people on the planet, meeting. A few longshot/lotto/lightning bolts later, we have to calculate the odds that one particular sperm cell out of millions with one particular combination of genes will encounter a particular egg cell with a particular set of genes... you see. The 'odds' of you being here are astronomical. But what does that prove? You're here.

Knowing how long the odds are may deepen our personal appreciation of the things we have. Such as you, such as any human being. Such as birds and feather pillows and KFC. But the odds don't change what we have, or materially affect how these things got here.

However you object to my use of the word 'lotto' because each time the trait was to arise - that is approximately what the odds of it arising from a beneficial mutation is.

You have a point. The overwhelming majority of mutations that occur have no effect at all, as you know. But this is a lottery where one species of animals holds all the tickets. Given enough time, someone's going to hit it. For just about any mutation. And it's possible to have multiple winners.

The whole longer arms thing means nothing because I am not arguing that with you - I know that -- by the way that is not a mutation at this point anyway.

It may not arise from a mutation, though it is genetically determined. My point is that this kind of variation accounts for most of the developments in bird evolution. Feathers are elongated scales. Increased feather lengths would come about in the way I described. At certain point in length and shape the creature would find itself leaving the ground. Flight would be a novel development and likely the thing that makes us use the word 'bird.' But it does not involve a 'novel trait' mutation.

Many other features of birds already existed in coelurosaurs, as I described.

Natural Selection acts AFTER the mutation occurred - I am talking about the odds of obtaining the beneficial mutation in the first place..[...]

[...] I concede that it is NOT impossible but you refuse to demonstrate what the chances of a benefeficial mutation that introduces a novel trait are (which is why I assume it to be odds of winning the lottery - and quite reasonable since there are some in this board who have debated if a beneficial mutation is even possible)

I don't know who, other than creationists, doubts beneficial mutation is possible. Geneticists often caution us that the word is subjective, though. Mutations tend to alter things so you gain one thing and lose another. Whether this is a net benefit or a net loss for a creature depends on whether the tradeoff confers an advantage in reproduction or survival. This is a function of the environment, mainly, not the mutation per se.

Edited by Archer Opterix, : Grammar.


Archer

All species are transitional.


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jar
Member
Posts: 31774
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.6


Message 58 of 111 (345564)
08-31-2006 9:38 PM
Reply to: Message 57 by Archer Opteryx
08-31-2006 9:32 PM


Re: Summary ..
Can I ask another stupid question?

Isn't the only way to determine beneficial by hindsight?

It seems to me that the difference between a beneficial and not beneficial mutation is only which one passed the filter.

Is there something about a mutation that would make it beneficial or harmful other than the filter?


Aslan is not a Tame Lion

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ikabod
Member (Idle past 2834 days)
Posts: 365
From: UK
Joined: 03-13-2006


Message 59 of 111 (345670)
09-01-2006 8:47 AM
Reply to: Message 58 by jar
08-31-2006 9:38 PM


Re: Summary ..
a very non stupided question ...

the whole point is its a dynamic , interedendant system that every creature lives in , the whole system IS a filter , and getting through is the only measure of good / bad / indifferent

an single mutation to a creature can be benificial and harmful and neutral and a given point in that creatures liniage .

eg a creture may mutate so that it hasd a dark blue spot on its tail , seem s to have no effect on creature

time passes , a new periditor has evoled near by that happens to have eye that are very good at spotting deep blue , and so this preiditor nearly kills off our creature by hunting .

more time passes and the pressure from the preiditor has selected those creatures in the population with that can feed in the darker hours of the day around dawn and dusk , this population has sleceted for vision that sees better in the dark , now this so happens that for individuals that have good low light vision the deep blue spot is a good way spotting fellow creatures ands becomes important trait in finding a mate , and hence breeding .

thus we have a mutation being all 3 types over a prolonged period , set along side changes to perdation , enviroment and breeding condistions .

it has been said if you rewound evolution and re run it would you get the same results ... and the answer given is maybe not .. you would end up with a lot the same but the steps and stages could be diffrent .

as the measure of benifit / harm can only be seen after the creaturte has survived or died out , hindsight is the only tool .


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Hawks
Member (Idle past 4487 days)
Posts: 41
Joined: 08-20-2006


Message 60 of 111 (345963)
09-02-2006 5:00 AM
Reply to: Message 58 by jar
08-31-2006 9:38 PM


Re: Summary ..
Is there something about a mutation that would make it beneficial or harmful other than the filter?

I would say that in some cases it is possible to predict with reasonable accuracy whether or not a certain mutation is beneficial/harmful. Since we know that certain genes are absolutely vital for survival, mutations that render these genes non-functional will by necessity be harmful (to conceive of such a mutation is easy - just delete the entire gene). To predict if a mutation would be beneficial might be more difficult, but given that an often given definition of a mutations is something like "A change in a DNA sequence", I'd like to give an example of a mutation that is highly likely to be beneficial in a certain environment: it is well known that bacteria often acquire resistance to antibiotics via horizontal gene transfer. Thus, a bacterium that has acquired an antibiotic resistance gene (which should fit the definition of a change in DNA sequence) would most likely have acquired a beneficial mutation (assuming that said antibiotic is common in it's environment and that the bacterium was not already resistant).

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