Understanding through Discussion


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Author Topic:   What would a transitional fossil look like?
Faith
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Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 151 of 400 (850777)
04-14-2019 11:56 AM
Reply to: Message 135 by dwise1
04-13-2019 3:12 PM


Re: Comparisons by Faith, the fun continues
The differences in body structure remain telling. Sorry.
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Faith
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Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 152 of 400 (850778)
04-14-2019 12:03 PM
Reply to: Message 138 by PaulK
04-13-2019 3:26 PM


Re: Thought Experiment for Faith
All those phenomena are what I'm calling "superficial, that is they are not structural.
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Replies to this message:
 Message 153 by PaulK, posted 04-14-2019 12:10 PM Faith has responded
 Message 160 by caffeine, posted 04-14-2019 12:55 PM Faith has responded

    
PaulK
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Posts: 14819
Joined: 01-10-2003
Member Rating: 3.5


Message 153 of 400 (850779)
04-14-2019 12:10 PM
Reply to: Message 152 by Faith
04-14-2019 12:03 PM


Re: Thought Experiment for Faith
quote:

All those phenomena are what I'm calling "superficial, that is they are not structural.

Please explain your difference between “superficial” and “structural” and how you can make this determination. Start with new kinds of eyes.


This message is a reply to:
 Message 152 by Faith, posted 04-14-2019 12:03 PM Faith has responded

Replies to this message:
 Message 155 by Faith, posted 04-14-2019 12:13 PM PaulK has responded

    
Faith
Member
Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 154 of 400 (850780)
04-14-2019 12:12 PM
Reply to: Message 139 by dwise1
04-13-2019 3:54 PM


Re: Thought Experiment for Faith
I only compared dogs and cats, and pointed out the difference in rigidity versus flexibility in their respective skeletons, plus the fact that cats move with their heads below their shoulders but dogs' heads are above their shoulders. I also added behavioral traits as a differentiator. I have said nothing about tetrapods in general, which are too various to mention in this context.

This started with my suggestion that I would differentiate species from one another by their body build. All dogs have the same basic build, yes also bulldogs and whippets. You would know that if you bothered to think about it. All cats have the same body build, including both felis and panthera. Yes I was also talking about the genome because the body build is of course programmed in the genome.

Reading back through the thread might help some of the more reading challenged here.


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Faith
Member
Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 155 of 400 (850781)
04-14-2019 12:13 PM
Reply to: Message 153 by PaulK
04-14-2019 12:10 PM


Re: Thought Experiment for Faith
I'm talking about body build, skeleton, not organs.
This message is a reply to:
 Message 153 by PaulK, posted 04-14-2019 12:10 PM PaulK has responded

Replies to this message:
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Faith
Member
Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 156 of 400 (850783)
04-14-2019 12:21 PM
Reply to: Message 147 by edge
04-13-2019 8:41 PM


Re: Thought Experiment for Faith
So, are you saying that since all trilobites have three lobes they are not variable enough to say that they evolved into separate species?

Well, as long as the three lobes are arranged as they are in all the trilobites, yes.

Would you say the same thing about tetrapods?

No because all tetrapods do not have the same body structure. There are many species of tetrapods, which all vary in many ways within their genome or body build. So as I've been considering it, dogs are a species; cats are a species. Etc.

Edited by Faith, : No reason given.


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Replies to this message:
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PaulK
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Posts: 14819
Joined: 01-10-2003
Member Rating: 3.5


Message 157 of 400 (850784)
04-14-2019 12:22 PM
Reply to: Message 155 by Faith
04-14-2019 12:13 PM


Re: Thought Experiment for Faith
quote:

I'm talking about body build, skeleton, not organs.

So you just happened to arbitrarily exclude the lead example without mentioning it. And implicitly admit that you have no answer to it.

And you don’t seem able to explain your criteria either.

What a surprise.


This message is a reply to:
 Message 155 by Faith, posted 04-14-2019 12:13 PM Faith has responded

Replies to this message:
 Message 158 by Faith, posted 04-14-2019 12:23 PM PaulK has responded

    
Faith
Member
Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 158 of 400 (850785)
04-14-2019 12:23 PM
Reply to: Message 157 by PaulK
04-14-2019 12:22 PM


Re: Thought Experiment for Faith
Problem is YOU don't seem able to follow a simple argument.
This message is a reply to:
 Message 157 by PaulK, posted 04-14-2019 12:22 PM PaulK has responded

Replies to this message:
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PaulK
Member
Posts: 14819
Joined: 01-10-2003
Member Rating: 3.5


Message 159 of 400 (850786)
04-14-2019 12:34 PM
Reply to: Message 158 by Faith
04-14-2019 12:23 PM


Re: Thought Experiment for Faith
quote:

Problem is YOU don't seem able to follow a simple argument.

That is hardly likely to make you forget to mention that you are excluding organs. Especially when explaining why new types of eyes should not be considered a significant change.

Nor is it a good reason for you to avoid explaining the distinction you made.

The REAL problem of course is that you are bluffing because you don’t know what you are talking about. But you’re too dishonest to admit that.


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caffeine
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Posts: 1624
From: Prague, Czech Republic
Joined: 10-22-2008
Member Rating: 5.7


(2)
Message 160 of 400 (850787)
04-14-2019 12:55 PM
Reply to: Message 152 by Faith
04-14-2019 12:03 PM


Re: Thought Experiment for Faith
All those phenomena are what I'm calling "superficial, that is they are not structural.

We've discussed this before, and I still struggle to see where you're coming from. Yes, trilobites are all three-lobed; this is the basic underlying structure of a trilobite; though within this structure there is enormous variety. You see this variation as superficial for reasons that make no sense to me.

If this was a statement alone we could just leave things there - you just have an odd interpretation of what 'superficiality' means. But you then go on to insist upon the supposedly deep structural differences between dogs and cats, which is simply bizarre. Structurally, dogs and cats are almost identical. You say below in your response to PaulK that you're talking about skeletal structure, not about internal organs. This is somewhat arbitrary, but not a problem - let's take a look at cat and dog skeletons.

Cats and dogs both have a vertebral column. In both this develops initially in the foetus as a collagen rod, which is later replaced by bone - the remaining collagen forming disks between the vertebrae. Cats have seven next vertebrae, thirteen chest vertebrae, 7 lumbar vertebrae, and 3 sacral vertebrae (can't think of a common name for 'lumbar' or 'sacral'). Dogs, exactly the same.

From the vetebrae come four limbs, in both dogs and cats. The limbs are made up of one long, thick bone; then two thinner long bones, then four carpal or tarsal bones, then the toe or finger bones - on which the animal stands. This is exactly the same in cats and dogs. There is a bone covering the joint between the thick long bone and the two thinner long bones in the hind legs, but not in the forelegs; in both dogs and cats. There is usually a fifth toe or finger bone, which is much smaller than the rest and not used in walking, in both dogs and cats.

Dogs usually have 13 pairs of ribs. Cats usually have 13 pairs of ribs.

Then we can look at the skull. Dogs and cats have quite distinctive skulls, compared to other mammals. But not compared to each other. Exactly the same bones fuse to form a skull in cats as in dogs. Now, the bones are not quite the same shape - dogs usually have a much more extended maxilla, example. But, thanks to human selective breeding, this is not always the case - look at a French bulldog for example.

But this is where I fail to see your distinction from trilobites. Trilobites all have three lobes, yes - but their relative size and shape, their internal subdivisions, their articulations and their degree of flexibility vary enormously. And all this variation you see as merely superficial.

Dogs and cats have exactly the same skeletons. The similarities here are much deeper and more fundamental than an overall concept like being made of three lobes - we're talking a few hundred bones with exact counterparts in dogs and cats in exactly the same place. And yet, in contrast to trilobites, you consider small variations in the size and shape of these bones to be fundamental differences. Except this is no longer the case when we look at the variation in size and shape of the bones between different breeds of dogs - despite the fact that the variation here is greater than that between cats and wolves.

You mention flexibility as some kind of deep, fundamental difference. Now, I'm not sure if it's actually true that cats are bendier than dogs, but even if it were - why is a slight difference in exactly the same bone structure to allow it to bend more fundamental? And why, if it's fundamental for cats and dogs, is it not for trilobites; since there the variation is much greater. There are trilobites whose three lobes are connected in such a way that they would have been perfectly rigid and straight, and others that could roll up into a ball.

I think that you view the differences between cats and dogs as being more fundamental than those between different families of trilobites only because they're so much more familiar to you.


This message is a reply to:
 Message 152 by Faith, posted 04-14-2019 12:03 PM Faith has responded

Replies to this message:
 Message 161 by Faith, posted 04-14-2019 1:07 PM caffeine has responded

  
Faith
Member
Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 161 of 400 (850789)
04-14-2019 1:07 PM
Reply to: Message 160 by caffeine
04-14-2019 12:55 PM


Re: Thought Experiment for Faith
Structure basically means skeleton, basic build, basic structure; "Superficial" characteristics are like fur color, eye color, things that vary regularly from generation to generation, including such things as changes in overall size, or elongation of the body and so on: they don't change the basic structure, just stretch or compress it. A chart of all the dog breeds shows the same skeletal structure in all of them.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 160 by caffeine, posted 04-14-2019 12:55 PM caffeine has responded

Replies to this message:
 Message 164 by caffeine, posted 04-14-2019 1:11 PM Faith has responded

    
caffeine
Member
Posts: 1624
From: Prague, Czech Republic
Joined: 10-22-2008
Member Rating: 5.7


(1)
Message 162 of 400 (850790)
04-14-2019 1:10 PM
Reply to: Message 154 by Faith
04-14-2019 12:12 PM


Re: Thought Experiment for Faith
Further to my previous post:

cats move with their heads below their shoulders but dogs' heads are above their shoulders.

If this were true, how on earth would this be fundamental; when all that is required is exactly the same bones joined at a slightly different angle.

And of course it's not even true. Cats often move with their heads held high

and vice versa

In another post I think you wrote 'stalking', rather than simply moving, but if that's what you meant then of course all dogs and cats go low when stalking

Incidentally, with regards to the last picture, awwwww.


This message is a reply to:
 Message 154 by Faith, posted 04-14-2019 12:12 PM Faith has responded

Replies to this message:
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Faith
Member
Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 163 of 400 (850791)
04-14-2019 1:11 PM
Reply to: Message 162 by caffeine
04-14-2019 1:10 PM


Re: Thought Experiment for Faith
Sometimes. Do try to get the general drift. ALL the dog breeds are illustrated with heads high. MOST cat skeletons are illustrated with heads down in a walking gait. Dogs do NOT stalk the way cats do.

Edited by Faith, : No reason given.


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caffeine
Member
Posts: 1624
From: Prague, Czech Republic
Joined: 10-22-2008
Member Rating: 5.7


Message 164 of 400 (850792)
04-14-2019 1:11 PM
Reply to: Message 161 by Faith
04-14-2019 1:07 PM


Re: Thought Experiment for Faith
Structure basically means skeleton, basic build, basic structure; "Superficial" characteristics are like fur color, eye color, things that vary regularly from generation to generation, including such things as changes in overall size, or elongation of the body and so on: they don't change the basic structure, just stretch or compress it. A chart of all the dog breeds shows the same skeletal structure in all of them.

Did you read my post? It's point was that cats, too, have the same basic skeletal structure.

Edited by caffeine, : Added the word 'skeletal'


This message is a reply to:
 Message 161 by Faith, posted 04-14-2019 1:07 PM Faith has responded

Replies to this message:
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Faith
Member
Posts: 30962
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 165 of 400 (850793)
04-14-2019 1:14 PM
Reply to: Message 164 by caffeine
04-14-2019 1:11 PM


Re: Thought Experiment for Faith
I've answered that a million times already.
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