Did We Have "Reptilian" Ancestors?

Science

(Herculean Skeptic) #141

I don’t know whether they are or not. I’m saying that if you offer to do so, no one can say that they weren’t given the opportunity. It just seems as though, the way things are right now, the mudslinging is used against you. “See,” anyone can say, “they don’t even give them a chance to prove themselves…” Whether or not it is true.


#142

so your agrument is basically the argument from common similarity. right?

we can find intermediate stage between vehicles too. but it doesnt prove any common descent:

(image from Fleet Insurance - Trident Business and Commercial Insurance Broker)


(Timothy Horton) #143

The ID pushers have had 20 years’ worth of opportunity. They can still start doing so any time they want. It’s obvious they have no desire to do science properly because the scientific community isn’t their target audience.


(Herculean Skeptic) #144

So, then, if you offer to help, you believe that they will not take you up on the offer?

Then, you win.


(Timothy Horton) #145

When their pseudo-science propaganda is exposed for the garbage it is everyone wins.


(Herculean Skeptic) #146

Like Dr. Phil says, “How’s that workin’ out for ya?” You need a new course of action. Twenty years and look at the trend.


(Timothy Horton) #147

Actually the trend seems to be going science’s way. With the internet and social media it’s harder every day for the ID-Creationists to pass their garbage. In fact if it weren’t for the concerted efforts of the DI “Intelligent Design” would have dried up and blown away years ago.

I’ll stay the course against the DI’s chicanery and anti-science propaganda, thank you. You are free to coddle them as much as you like.


#148

Here are 29 hypotheses:

http://www.talkorigins.org/faqs/comdesc/


#149

Please cite the features that makes the one of these vehicles intermediate between the other two.


#150

Here is one:


(Herculean Skeptic) #151

Hahaha… .well, I’ve got no authority with anyone. So whatever I do or don’t do makes no difference. Unless I change your mind. :slight_smile:


(Timothy Horton) #152

Or I yours. :slightly_smiling_face:


(John Harshman) #153

No. The principle of parsimony, as applied to phylogeny, attempts to minimize the number of separate evolutionary events. If you see two species with legs, parsimony would require that those legs originated in a common ancestor as a single event, rather than as multiple events in different ancestors. That’s all. Now, when you see a putative atavism, as in the whale, the simplest explanation isn’t that it’s a completely new organ that just happens to resemble one lost by its ancestors but that it’s a re-expression of the same genes involved in the prior organ. Almost all those genes have other functions, so all that’s required is a regain of expression in a particular place, which could be as simple as a single mutation in an enhancer site, or perhaps even random fluctuation in the amount of expression of some gene in some group of cells.

A snake is a poor example, as snakes are highly derived amniotes. Stick with the worm. In fact a good stand-in for that worm would be Branchiostoma, also known as Amphioxis; it has a rodlike structure called a notochord plus a number of branchial supports. Something like that would be the beginning of a skeletal system. It also has a sort of fin, just a long extension of the body wall. And there you have that beginning.

That’s not what parsimony leads to. The point of parsimony is that the simplest explanation for similar features is a single origin. The point about truly new features being rare is completely separate and has nothing to do with parsimony. Now of course truly new features do happen; it’s just that the vast majority of what you think of as new features are just modifications of old ones.

Leaving aside the misunderstanding of what “parsimony” means, why doesn’t it make sense to you?


#154

If you had observed tetrapods evolving you probably wouldn’t label anything as being new since limbs evolved from fins with transitional steps in between.

image


(S. Joshua Swamidass) #155

We do see the process continuing in many ways. For example, seals have flippers that are intermediate between legs and whale fins.


#156

But seals are still seals!!! . . . or so we are told. When you are sworn not to accept anything as being transitional, no matter what it looks like, it is hard to come up with examples that would break through that dogmatic barrier.


(Mikkel R.) #157

Not really, no.

I’m asking you to explain why something exists, which would be expected to exist if common descent was true, but there is no reason to exist if common descent isn’t true.

There are two aspects to this argument.

  1. Why was a whale born with vestigial hindlimbs with the bone structures found in the hindlimbs of countless other mammals?
  2. Why can the genetic and physiological attributes of organisms be sorted into objective nesting hierachies?

With respect to the second point, you keep claiming that designed objects can also do that, but you have yet to do it.

I fail to see a car or truck with an ativistic appendage here. How is three sizes of vehicle at all analogous to a whale born with vestigial hindlimbs? Why should there be whales born with vestigial hindlimbs if whales did not evolve from four-limbed ancestors?


(Bill Cole) #158

Gene loss occurring is not an issue it is the pattern of gene loss that looks troubling. Calling gene loss the cause of the patterns such as Sal’s flower and the dependency graph is speculation. This is the fact of the case as you cannot independently confirm the pattern is caused by gene loss. You make this assertion only as your automatic conclusion comes from assuming common descent is the complete cause of the pattern.

No tree is not an adequate null as you have not confirmed that the tree pattern you are observing is the result of common descent. You’re only strategy here has been to assert that common descent is the only explanation. I do agree with you that common descent does explain some of the similarities and differences that we observe but it is only a partial explanation. I think we both agree that common descent does not include new features.

I have only peripherally looked at the data on whale evolution and agree there is positive evidence as Rum has been providing. The problem is that when you see a feature change that looks trivial from the morphological data the cellular changes may be far from trivial and include significant changes in DNA that would be highly improbable with a trial and error search. Again, I agree for argument sake that common descent does not include new features so this point is made for only people who believe that the diversity of life is the result of reproduction and the resulting variation alone.


(Herculean Skeptic) #159

That was the main cause of the misunderstanding…


(Mikkel R.) #160

Why? What looks troubling about it?