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Author Topic:   What mutations are needed for a particular trait (e.g. wings) to arise?
Archer Opteryx
Member (Idle past 1943 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.


This message is a reply to:
 Message 1 by skepticfaith, posted 08-29-2006 5:45 PM skepticfaith has responded

Replies to this message:
 Message 9 by jar, posted 08-30-2006 11:09 AM Archer Opteryx has responded
 Message 12 by skepticfaith, posted 08-30-2006 4:10 PM Archer Opteryx has responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 16 of 111 (345115)
08-30-2006 5:15 PM
Reply to: Message 12 by skepticfaith
08-30-2006 4:10 PM


Re: feathers and flight
skepticfaith writes:

Ok - that was an interesting read, but it does not cover what I am saying.

You asked several questions. I only addressed one: your request for a catalog of the changes that would be needed.

It's a good place to start. It helps to have a sense of that before getting into the specifics of how mutations arise and are selected. The article does a good job of listing the structures that are implicated in a transition from dinosaurs to birds.

The transition from dinosaur to archaic bird was really not so vast. Archaeopteryx is, skeletally, just another coelurosaur. But it had feathers, and a true flight capability.

(In fact, two specimens of Archie--The Solnhofen Specimen and the Eichstätt Specimen--were at first misidentified as Compsognathus, a ground-running coelurosaur. That's how dinosaurian its skeleton is.)

Coelurosaurs were already set up for the change. I mentioned the hollow bones and the high metabolism. They were also carnivores. One of the anatomical features that tends to go with predation is good eyesight--especially stereoscopic vision. Obviously, this is also helpful to a creature that flies.

The similarities are so strong that cladistics experts today no longer consider birds a separate category from dinosaurs. They have adopted the terms 'non-avian dinosaurs' for those groups that went extinct and 'avian dinosaurs' for those creatures whose eggs you eat every morning. Modern birds are coelurosaurs.


Archer

All species are transitional.


This message is a reply to:
 Message 12 by skepticfaith, posted 08-30-2006 4:10 PM skepticfaith has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 23 of 111 (345154)
08-30-2006 6:23 PM
Reply to: Message 9 by jar
08-30-2006 11:09 AM


Re: just a couple questions
jar writes:

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

Sure. I live in a part of the world where fish fly. It's very exciting to see.

Interesting you say the word 'intermediate.' It's true these animals have very limited flight capabilities in our time. Yet they serve as excellent illustrations of the fact that creatures don't require the 'magic' arrival of a highly evolved feature. All they need is a mutation that stretches something a bit--a fin, some skin--and for the change to give some advantage.

Flying fish can't touch modern birds when it comes to flight skills. But they really do fly for short distances and this in itself confers a real survival advantage. It can make all the difference in evading a barracuda.

I suspect the ability of ancient fish to move into ever shallower water, and then onto land, came about in a similar fashion. The ability to get around in shallow water, and eventually on land, would be very useful in staying out of range of predators.

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?

Right now a lot of new discoveries are being made. It's hard to say who is related to who yet, but it's clear a variety of feathered coelurosaurs were running around. Some lines evolved flight capabilities, some didn't, some who did later dropped the flight adaptation, and so on. Some lines represent bird ancestry and some represent, in the long run, dead ends.

You'll notice most of the newest dinosaur-bird fossils coming from China, where some unusually find sand in Jurassic times enabled the preservation in fossils of delicate structures that usually get lost, such as feathers, fur, and skin.

A very exciting find, Dromaeosaurus, is an example of a Velociraptor cousin with feathers. It didn't fly. But the 'raptors' were a succesful group of animals.
http://news.bbc.co.uk/2/hi/science/nature/1296102.stm

Here's a look at the flight characteristics of one early bird, Microraptor:
http://www.livescience.com/animalworld/051014_flying_dino.html

Here's a colorful scroll-through gallery of feathered dinosaurs:
http://www.livescience.com/bestimg/index.php?url=Avian_Velociraptor_00.jpg&cat=avianancestors

The Velociraptor--a ground-based dinosaur--had a wrist that enabled it to make a fast, sweeping lateral movement with its forearms. This feature helped it grab prey. What's fascinating is that the same movement is used by modern birds when they make their flight stroke. When birds flap their wings, they 'grab air' using the same gesture their ancestors used to grab prey.

The term 'failures', though, is a bit loaded. It implies that every line of coelurosaurs had to evolve into birds, so the 'successes' are those who make it and the 'failures' are those who don't. That's not really how it goes. The creatures just mated as they mated, mutated as they mutated, and went in their different directions. One result was birds.

Edited by Archer Opterix, : Concision.

Edited by Archer Opterix, : Typo.


Archer

All species are transitional.


This message is a reply to:
 Message 9 by jar, posted 08-30-2006 11:09 AM jar has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 38 of 111 (345477)
08-31-2006 3:22 PM
Reply to: Message 1 by skepticfaith
08-29-2006 5:45 PM


Re: mutations and math
How many random mutations would it have taken to create a bird and does this even seem remotely possible?

Well, 'to create a bird' is a biased way to say it. (And I know I've seen this exact same question worded this exact same way elsewhere.) You would have a series of mutations in small coelurosaurs that result in a Compsognathus or that lead to a Velociraptor, a series of mutations that lead to a Dromaeosaurus and mutations that result in an Archaeopteryx, and mutations that result in a Microraptor and so on.

At what point do we say a group of coelurosaurs have become birds? They never really stop being coelurosaurs; in that sense, birds represent just a specialized kind of dinosaur. And whether this process represents an act of 'creation' is an open question. It's one a theistic evolutionist would be very interested in considering with you, I'm sure.

As to whether a dinosaur-bird transition 'seems even remotely possible': a look at the fossil evidence makes it seem not only plausible but convincing to a great many unbiased observers.

Would it not take a series of random mutations (over time of course)

Of course. Mutations happen. This has been observed. The process has been described and demonstrated.

With a lot of time, a lot of mutations can happen.

It's a natural process.

- the odds of this happening being almost impossible?

This is the second time in two sentences you've invoked the spectre of impossibility. You wield your incredulity like a shield.

Not impossible at all. It happens as I described.

If you lower that shield just a little bit, you can see better over the top.

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.

I supplied this in an earlier post. What's interesting is that coelurosaurs didn't need a whopping amount of changes.

Features coelurosaurs already had going for them were:

1. hollow bones
2. small body
3. high (endothermic) metabolism
4. bipedal stance
5. flexible wrist
6. stereoscopic vision
7. feathers

The only mutations needed are those that put them into the air. The main change needed in this category would be the growth of plentiful arm feathers. Feathers already give you the required wing shape when they lie in layers.

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?

Someone is trying to construct an argument from incredulity here. Argument from incredulity is a fallacy. To say 'I don't believe it' proves nothing about the universe. It only testifies to an individual's belief.

If I told you I find the law of gravity impossible to believe in, and if I heaped ridicule on such a 'magical' belief, would this shake youre belief in the law of gravity? No. Why should it? The law of gravity has been demonstrated.

If I told you that instead of the law of gravity, everything is held into place on earth by the invisible benevolent paw of a giant Hello Kitty--a being whose existence I cannot prove, but take to be obvious--would you find that persuasive? Would you consider that a less 'magical' belief than the law of gravity, or more?

This is why argument from incedulity is not evidence against a proposition. People believe and disbelieve any number of things. Science asks for evidence.

This particular argument from incredulity depends on backward math. One can make anything seem 'impossible' by working the odds this way. It's an easy game to play.

I could argue by the same method that Abraham Lincoln was never president of the United States. Why? Because the odds of him doing it were too long. Do you know how many little things have to happen for someone to get that office? How many accidents of fortune and fate? And with him coming from such a poor background and all...

I could show you the odds of Lincoln getting to the White House were astronomical. And you might even agree. But would that prove to you that Lincoln was never president? Would you even consider it a valid argument?

The truth is that the odds of any one person getting that office are astronomical. But the odds that somebody somewhere will get that office are 100%. The job exists and someone is going to fill it. All that matters in Abe's case is that we show he got the gig.

Another example: you. The odds of any of us existing as individuals right now are far more astronomical than Abe's shot at the top job. Think how many sperm cells and egg cells go for naught every day. Do the math. Does that prove you were never born? Of course not. You're here.

It would be silly for me to try to argue from the odds that you do not exist. The math might be impressive but that would not disprove the reality of you. People are born every day. On one day in the recent past, you were one of those people. It happens.

Evolution is just the idea of birth extended across generations. The same thing applies. No one can say what 'the odds were' of coelurosaurs evolving along the lines they did. The fact that many evolved along non-avian lines does show there was nothing sure about evolving in the direction of birds. But mutations do happen. They happen every day. Living creatures, coelurosaurs included, are going to evolve in some direction. And the record indicates that some coelurosaurs evolved into birds. Whatever the odds of it happening might have been, only one thing matters in hindsight: it did.

Edited by Archer Opterix, : Typos.

Edited by Archer Opterix, : Spelling.


Archer

All species are transitional.


This message is a reply to:
 Message 1 by skepticfaith, posted 08-29-2006 5:45 PM skepticfaith has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 40 of 111 (345491)
08-31-2006 4:37 PM
Reply to: Message 39 by skepticfaith
08-31-2006 4:01 PM


Re: Summary ..
Doest this sound about right or are there some problems with above or things I left out?

You're leaving out everything you've been shown that doesn't support the argument from incredulity you are eager to make.

You've been shown the invalidity of this argument. You have left that out. That makes the rest off the point. The odds of a thing happening don't really matter after the fact.

Where you leave out the most is in your effort to cherry pick aspects of bird evolution to heighten the effect of implausibility. You picked up the word 'Lottery' from some examples you were shown (while missing their point) and now it's your favorite word.

But you omit mention of factors that come into play when we discussing changes in organisms in nature. You omit any consideration, for example, of the time scales involved. More centuries, more opportunity for changes, more changes. Lower odds.

And in your eagerness to use two of you rother favorite words--'chance' and 'random'--you overlook the word 'natural.' Natural selection, as the term implies, is a natural process. It acts in predictable ways and hardly involve astronomical odds.
___

The important thing you are overlooking now is that evolutionary change does not involve a series of lightning strikes. This is far more characteristic of creationist theories than the theory of evolution.

Some people, for example, are born with longer arms in proportion to their bodies than others. Some are born taller than others. There is nothing 'Lottery-like' about this. Being with arms that are longer or shorter than the average is just natural variation within a population.

Let's say something in the environment gave a survival or reproductive advantage to, say, people possessing longer arms. Some generations later you'd see longer arms on most people. The average would move. If that environmental factor still continued to play a role, people with longer arms by the new average would still have a survival or reporductive advantage. A few generations later the average arm length of the population would again have lengthened.

You tend to use the words 'chance' or 'random' to mean 'long odds! lightning strikes! magic!' But what are the odds a person will be born with arms that are longer or shorter than average? Pretty much 50% either way. No long odds. No lightning strikes.

Now notice an important difference. Being born with arms that are longer or shorter than average is a matter of chance, even if chanes are 50/50. But the subsequent interaction of this feature with the environment is not. Natural selection is not random or chance. It is natural. It acts a certain way, unconsciously, like water flowing downhill. The direction of natural selection, like the direction of water, follows natural laws.

This kind of thing comes into play when you talk about bird evolution. Some creatures will have longer feathers on their arms than others. The odds of having feathers that are longer would be around 50%. Nothing dramatic. Natural variation. But it the longer feathers confer a survival advantage--they are warmer--or a reproductive advantage--the opposite sex thinks the feathers look cool--the trend will be toward longer and longer feathers.

Edited by Archer Opterix, : Concision, spelling.

Edited by Archer Opterix, : Typo.


Archer

All species are transitional.


This message is a reply to:
 Message 39 by skepticfaith, posted 08-31-2006 4:01 PM skepticfaith has responded

Replies to this message:
 Message 45 by skepticfaith, posted 08-31-2006 5:48 PM Archer Opteryx has responded

  
Archer Opteryx
Member (Idle past 1943 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.


This message is a reply to:
 Message 45 by skepticfaith, posted 08-31-2006 5:48 PM skepticfaith has not yet responded

Replies to this message:
 Message 58 by jar, posted 08-31-2006 9:38 PM Archer Opteryx has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 64 of 111 (346148)
09-02-2006 11:47 PM
Reply to: Message 63 by crashfrog
09-02-2006 1:36 PM


Re: It's time to play...
Double post. Please excuse.

Edited by Archer Opterix, : Error.


This message is a reply to:
 Message 63 by crashfrog, posted 09-02-2006 1:36 PM crashfrog has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 65 of 111 (346149)
09-02-2006 11:48 PM
Reply to: Message 63 by crashfrog
09-02-2006 1:36 PM


Re: It's time to play...
[qs]Beneficial, Neutral, or Harmful!
crashfrog[/b]!

Suppose that a bacterium recieves a mutation that confers resistance to an antibiotic that is not present in the environment. Beneficial or neutral?[/qs]

Neutral.

Suppose further that the mutation causes resistance by changing a gene product that allows the bacterium to metabolize lactose when glucose is not present. The protein no longer has that function but now promotes resistance against the antibiotic. Neither lactose nor the antibiotic are present in the environment, and glucose is present. Beneficial, neutral, or harmful?

Um... Neutral.

The antibiotic is present, but lactose is not. Beneficial, neutral, or harmful?

Beneficial. The organism survives.

Lactose is present, but the antibiotic is not. Beneficial, neutral, or harmful?

If glucose still exists: Neutral.
If no glucose: Harmful. Organism loses potential food source.

Both lactose and the antibiotic are present. Beneficial, neutral, or harmful?

If glucose still exists: Beneficial. Resists antibiotic.
If no glucose: Bacterium has bad day.
- First, Beneficial. Resists antibiotic.
- Next, Harmful. Organism starves.

A new antibiotic is introduced that specifically targets the mutation. Wild-type bacteria are not affected. Beneficial, neutral, or harmful?

Harmful. The organism will croak. (No offense.) DOA. Sayonora.

....Do I win?

Edited by Archer Opterix, : Error.

Edited by Archer Opterix, : Restore text.


Archer

All species are transitional.


This message is a reply to:
 Message 63 by crashfrog, posted 09-02-2006 1:36 PM crashfrog has responded

Replies to this message:
 Message 68 by crashfrog, posted 09-03-2006 10:49 AM Archer Opteryx has responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 71 of 111 (346457)
09-04-2006 2:10 PM
Reply to: Message 68 by crashfrog
09-03-2006 10:49 AM


Re: It's time to play...
crashfrog:

Well, they were largely rhetorical questions

That's OK. They were largely rhetorical answers.

We have a winner!

YAAAAYYYY! I WIN! I WIN!
Oos! Oos! Oos! Oos! Oos!

I was really sweating that. (Humanities major.)

(Crashfrog, tell him what he's won!)

Um... a cookie?

Given our avatars, a dragonfly should suit.
;)

Edited by Archer Opterix, : Punctuation.


Archer

All species are transitional.


This message is a reply to:
 Message 68 by crashfrog, posted 09-03-2006 10:49 AM crashfrog has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 74 of 111 (346507)
09-04-2006 5:27 PM
Reply to: Message 72 by skepticfaith
09-04-2006 2:46 PM


haiku changes = novel traits
skepticfaith:

You can take your pick from the development of flight itself (which may have happened from a combination of different things but is still not very clear)

Bird evolution is still the subject of research but the general direction toward flight is clear enough.

You already have a creature that makes the forearm (flight) stroke of modern birds. It already has forearms covered in feathers that serve as insulation and date bait. It is already small and light and fast. There is no huge step involved for a creature of this sort, when grasping at something and splaying its forearm feathers, to find itself benefiting from lift beneath its wings. If this confers a survival or reproductive advantage--as well it might--subsequent generations will get better at keeping their toes off the ground. And off you go.

even simply the appearance of feathers - they are just elongated scales? How did it get from a scale to a feather?

They are not just elongated scales, as arachnophila observes. A number of mutations is implicated in such a metamorphosis. But that's the essence.

The point is that feathers are not a 'novel' feature in the way you described it earlier: a new organ. Feathers just represent an evolved--mutated--version of a body feature that already existed. A body covering evolved into a body covering.

That is a mutation that results in a physical change in the animal

Yes. Mutations can result in physical changes.

- a change in the function of a particular limb or organ.

Yes. Creatures do find new functions for features they have.

I know a dog that uses his nose to smell, just as his ancestors did 1,000,000 years ago. But he also uses his nose to push his supper dish so that individuals of the species Homo sapiens will get a certain point. This is a nose function unknown to his ancestors. In adapting to a new environment he has found a new function for his nose.

(And I dont' mean changes like long to short legs or size differences)

Intergenerational shifts in size and proportion are unremarkable in terms of genetics and 'odds.' But you can't dismiss them. These are factors that affect function.

Size and weight have a lot to say, for example, about whether a creature--or anything--can get into the air.

T Rex, like the first birds, was a kind of coelurosaur. But it's safe to say that Sue, for all her impressive physical capabilities, would have flown like brick. Wrong size body, wrong size arms.

You admit there is nothing extraordinary about a line of coelurosaurs growing smaller and lighter over succeeding generations as their forelimbs grow longer and quicker. What you don't want to admit is that trends like this are not trivial. In this case the trend in size would be crucial in enabling flight.

- I mean something extraordinary - of this magnitutde - a scale becoming a feather or change in the animal's locomotion ...

You insist on being shown an extraordinary, mega-magnitude evolutionary miracle that defies belief. But nothing extraordinary is called for. Small mutations over succeeding generations, acting in concert with natural selection, can do the job.

Most of the observed 'beneficial' mutations are with bacteria, algae etc..If there anything major as I described above,

There doesn't have to be anything 'major.'

Small mutations over succeeding generations, acting in concert with natural selection, can do the job.

Edited by Archer Opterix, : Quote credit.

Edited by Archer Opterix, : Clarity.

Edited by Archer Opterix, : Typo.

Edited by Archer Opterix, : Typo.


Archer

All species are transitional.


This message is a reply to:
 Message 72 by skepticfaith, posted 09-04-2006 2:46 PM skepticfaith has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 77 of 111 (347014)
09-06-2006 3:45 PM
Reply to: Message 76 by skepticfaith
09-06-2006 2:33 PM


Re: Lets get the list then...
skepticfaith writes:

Ok -- I am not the expert here.. Just convince me here.. What mutations have been observed that have resulted in physical changes for higher order animals (mammals, birds etc). Nothing drastic, just something that implies or suggests further evolutionary change. [....]

The specialists can field this, but one that comes to mind is the mutation that suppresses the growth of wisdom teeth in humans. This mutation appears with increasing frequency as time goes by and it meets the criteria you state. It is a 'physical change' in 'higher order animals' that 'implies or suggests further evolutionary change.' In this case, the 'further evolutionary change' it 'implies or suggests' is toward smaller jaws and, by further implication, larger brain cases.

Fossil evidence lends support to this hypothesis. Today's Homo sapiens already displays smaller jaws (and larger brain cases) than did archaic Homo sapiens and earlier hominids. The increasing loss of the wisdom teeth would continue a trend already in observable progress.

BTW I know of the immunity to disease - blood type mutations - excluding those ...

On what grounds do you exclude those? You did ask for evidence of physical changes. Changes in blood and body chemistry qualify as much as any other physical change.

Endothermic metabolism, for example, played an important development in the evolution of both birds and mammals. That's a physical change. But you can't point to endothermy like you can point to a feather or a smaller jaw. It happens at the level of blood and body chemistry.

On what grounds do you make this distinction between observable change you will accept as change and observable change you will not accept as change? Please clarify this. Until a rational distinction is established you're only saying 'Show me evidence for change except for some of the evidence for change.'

AO
_

Edited by Archer Opterix, : Typo.

Edited by Archer Opterix, : Concision.

Edited by Archer Opterix, : Typo.


Archer

All species are transitional.


This message is a reply to:
 Message 76 by skepticfaith, posted 09-06-2006 2:33 PM skepticfaith has responded

Replies to this message:
 Message 78 by skepticfaith, posted 09-06-2006 6:31 PM Archer Opteryx has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 82 of 111 (347378)
09-07-2006 8:48 PM
Reply to: Message 81 by ringo
09-07-2006 2:54 PM


Re: Ha ha.
The essence of your demands, skepticfaith... 'Well, that's not what I mean, show me this'... comes down to demanding 10 million years of vertebrate evolution in a 10-day experiment. This is not a realistic demand. And it is not needed to substantiate the validity of evolutionary theory.

Thresholds exist that affect our ability to observe. We operate on a human scale and some things in nature operate on vastly different scales. These thresholds have to be worked with as a practical matter, whether we are talking about microbiology (size), paleontology (time) or astronomy (distance).

Thresholds are normal. It would make no sense to deny the existence of protozoans just because we need microscopes to see them. If we've got the data we've got it.

And for evolution we do.

The mechanisms driving evolutionary change have been demonstrated. Mutations and the evolution of new abilities in organisms has been observed. Over time, changes accrue. Over enough time, enough changes can accrue to result in the kinds of metamorphases we see in the fossil record. And the relationships recorded there can be traced backward genetically from modern creatures. And geologists can correlate these findings with climate patterns and the placement of continents and oceans in earth's past. It's a solid theory.

To cite just one more example of vertebrate evolution (besides birds) that demonstrates the changes you want to see:

Wikipedia: Horse Evolution
http://en.wikipedia.org/wiki/Evolution_of_the_horse

Talk Origins: Horse Evolution
http://www.talkorigins.org/faqs/horses/horse_evol.html

BBC: Early Horses and Carnivorous Birds
http://news.bbc.co.uk/2/hi/science/nature/1651601.stm

BBC: Genetic Evidence of Horse Evolution in North America
http://news.bbc.co.uk/2/hi/science/nature/4618571.stm

But if you're unconvinced by any evolution that takes a microscope to see, and you insist on seeing this level of change with your own eyes with no resort to fossils, here's what you can do.

Take your vitamins and get plenty of exercise. Live 10 million years. Observe.

.

Edited by Archer Opterix, : Added link.

Edited by Archer Opterix, : Clarity.

Edited by Archer Opterix, : Punctuation.

Edited by Archer Opterix, : Typo.


Archer

All species are transitional.


This message is a reply to:
 Message 81 by ringo, posted 09-07-2006 2:54 PM ringo has not yet responded

Replies to this message:
 Message 84 by skepticfaith, posted 09-07-2006 9:24 PM Archer Opteryx has responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 83 of 111 (347379)
09-07-2006 8:51 PM
Reply to: Message 81 by ringo
09-07-2006 2:54 PM


Re: Ha ha.
I remember people saying 'Show me where any organism has been observed to evolve!'

Now they say 'Okay, okay--but show me where any other organisms have been observed to evolve!'

;)


Archer

All species are transitional.


This message is a reply to:
 Message 81 by ringo, posted 09-07-2006 2:54 PM ringo has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 102 of 111 (347458)
09-08-2006 12:23 AM
Reply to: Message 84 by skepticfaith
09-07-2006 9:24 PM


mutation links
skepticfaith writes:

Are there not any observed mutations at all ?

It's disconcerting to be asked this when, just a few posts ago, I described one.

Just give me the links to them whatever they are.

Mutations Documented & Discussed

Evolution of antibiotic-resistance in bacteria
http://www.pbs.org/wgbh/evolution/survival/enemy/

Evolution of 'conquistador' algae in the Mediterranean
http://tinyurl.com/fymwl

Evolution of nylonase from frameshift mutation
http://www.nmsr.org/nylon.htm
(Graphics are awful, but see the text)

Evolution of CCR5 sickle-cell mutation in resistance to malaria
http://anthro.palomar.edu/synthetic/synth_4.htm

Evolution of enhanced muscular development from myostatin mutation
http://www.ultimate-exercise.com/bravenewworld.html

More examples (HIV resistance, lactose tolerance, etc.)
http://www.talkorigins.org/indexcc/CB/CB101.html
http://www.talkorigins.org/faqs/mutations.html

If you want more specialized information, I recommend contacting EvC member Wounded King to begin.
___

Background & Context

How Mutations Occur
http://anthro.palomar.edu/synthetic/synth_3.htm

How Natural Selection Operates
http://anthro.palomar.edu/synthetic/synth_4.htm

Today's Synthetic Evolutionary Model: Darwin + Mendel
http://anthro.palomar.edu/synthetic/synth_9.htm

EvoTutor: Modes of Natural Selection
http://www.evotutor.org/Selection/Sl5A.html

Theodosius Dobzhansky. 'Nothing in biology makes sense except in the light of evolution.' The American Biology Teacher, March 1973
http://www.pbs.org/wgbh/evolution/library/10/2/l_102_01.html


Archer

All species are transitional.


This message is a reply to:
 Message 84 by skepticfaith, posted 09-07-2006 9:24 PM skepticfaith has not yet responded

  
Archer Opteryx
Member (Idle past 1943 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 104 of 111 (347461)
09-08-2006 12:34 AM
Reply to: Message 99 by Someone who cares
09-07-2006 11:31 PM


bird evolution
Tell me, in what part of that did the reptile aquire the neccessary info to start evolving wings!

Dear Someone who cares:

Please care enough to read the posts in this thread that address bird evolution before attempting to debate it. The questions you raise, and more, have been discussed with links to science sites provided.

Right now it is clear you lack the most basic knowledge of the views you hope to refute.

Welcome to EvC.

.

Edited by Archer Opterix, : Title.


Archer

All species are transitional.


This message is a reply to:
 Message 99 by Someone who cares, posted 09-07-2006 11:31 PM Someone who cares has not yet responded

  
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