What would a transitional fossil look like?

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You are not reading the right statement. But that one is true too. The structure remains as described, it's the superficial parts that vary, and if the ToE were true the structure would change too.

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Your original claim was that the “basic body plan” was unchanged. That allows for a lot more variation than you are admitting here.Indeed, all tetrapods have the same basic body plan so you should understand why we find that a very unimpressive piece of evidence for your ideas.Now do you have anything better than vague and dubious assertions ? Some actual serious analysis of trilobite differences for instance ? You know the sort of thing you should have provided when you started making that argument ?

You are breaking the rules again. Or is that still.

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Please keep discussion civil. Argue the position, not the person.

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EvC Forum: Rules

And just a little quote from Wikipedia on trilobite evolution. I’ll grant that a lot of that uses complex terms but “new types of eyes” seems simple and significant enough.Edited by PaulK, : Added link

We should expand upon that reference to tetrapods. Tetrapod is a superclass -- refer to the classical Linnean classification system: Kingdom, Phylum, Class, Order, Family, Genus, Species. So then Tetrapod is placed above Class (ignoring non-tetrapod classes -- eg, mammals, birds, amphibians, reptiles) and below Phylum (ignoring other phyla -- eg, chordates meaning vertebrates).So then what Faith is essentially arguing is that all amphibians, reptiles, birds, and mammals (which includes humans) are all of the same species. Which is just complete and utter loony-tunes batshit crazy.

That "sameness of the structure" is that of a tetrapod: basically four limbs, head able to move independently of the body (for the other option, thing of a fish), tail. As I describe in Message 139, it is a super-class, which includes all the classes below it: amphibians, reptiles, birds, mammals (including humans). Therefore, we have you arguing that all members of the super-class Tetrapod are of the same species. Such a position as you are making is absurd on the face of it.That basic tetrapod structure falls under the purview of HOX genes, which control the building of the overall body structure during embryonic development and during metamorphosis. One of the basic problems with changes of that HOX system is that it is most likely to result in the grotesque results which fuel creationist claims of "all mutations are malignant" and which would normally not be passed on to the next generation. That would include to mutations induced and studied in The Fruit Fly Room in the early 20th Century which included fruit flies with legs growing on their heads instead of antennae.Bottom line is that there is strong selective pressure against major changes in the basic body plan, so it should come as no surprise that there is a strong tendency to preserve that basic body plan. And you are violating most social norms by pretending to be surprised at the obvious.If all that went over your head, there are a series of music videos on YouTube by acapellascience (true to the name, he also does the instruments), one of which addresses this question: Evo-Devo (Despacito Biology Parody). All his videos are subtitled so you can read along.

Yes, that's why they are called trilobites. What did you expect? Your untrained opinion is noted.

I did say somewhere that my impression was that the genes for the basic structure did not vary much, so thanks for the confirmation. I showed no surprise at this as far as I know. "strong selective pressure" would explain it. And: I distinguish between different tetrapods, though apparently you don't.

The three lobed structure is the part of the trilobite that doesn't vary. I don't know why you people can't read, but enough is enough.

The chimp's being "our nearest neighbor" does not make its body structure as similar to ours as a cat's is to a dog's.Again, enough is enough.

Uh, no. Please stop your stupid lying.I do indeed distinguish between different tetrapods all the way down to the species level, which you have so far refused to do. So far, your argument has been that "basic structure" means that they are the same species. All of us disagree with that.Point us to the exact messages where you distinguished between different tetrapods. IOW, just what the fuck are you blathering on about?

Except that your entire argument was not about the phenotype (the basic physical structure), but rather the genotype. You had been going on and on about genomes and the different species genomes. Just what the hell do you think a genome is, anyway? Are you only pretending to be so ignorant and stupid or are you actually so afflicted?Small changes in the genome can result in large changes in the phenotype while large changes can result in little or no change in the phenotype (or are the terms "phenotype" and "genotype" above your ability to comprehend? -- with your all-too-apparent impairments it is difficult for us to know). Ultimately for evolution, the only real changes (ie, mutations) of importance are genetic (ie, in the genotype), though how important they are depends on how they are expressed (ie, in the phenotype) and selected for or against.So then, the touchstone is not physical appearance. There is a multitude of species which superficially appear to be similar (your stated preferred indication of relatedness here) and yet are completely unrelated. Eg, several marsupials who appear similar to placentals filling the same kinds of ecological niches; not in the least related genetically yet physically very similar. Whales and other cetaceans and fish, an utterly false "evolutionary sequence" that you yourself have recently argued for as a counter-example. Physically similar due to the demands of the environment, yet completely unrelated.IOW, your criterion for relatedness of mere physical similarity is completely false and complete and total BS.The true measure of relatedness is the genome and the way to measure relatedness is by comparing genomes, which includes comparing protein sequences. Genetically, chimps are indeed "our nearest neighbor{s}" (Jeez, woman! If you're going to live in this country, then at least learn the fucking language! -- the chimp's what for fuck's sake? (IOW, Do not use the possessive if you refuse to divulge just exactly what is supposed to be possessed!)). The true touchstone of relatedness is the genome, the genetics, the protein sequences.

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A touchstone was an assaying tool, a piece of slate-like stone. If you rubbed a piece of precious metal (eg, gold) against it, it would leave a mark. The color of the mark would tell you how pure that gold was. As a result, the term "touchstone" sued metaphorically meant some way to test how good something was.

So, are you saying that since all trilobites have three lobes they are not variable enough to say that they evolved into separate species?Would you say the same thing about tetrapods?

But that is the point, there is nothing in the genome to define what the final body structure will be. What we perceive as a final body structure is the culmination of many generations of embryonic cells multiplying and their gene expression changing in response to the cells that surround them and the signalling proteins they're exposed to.
This also means that changes earlier on in development carry a greater risk of damaging the individual as they can impact how cells interact later on in development. Therefore the innovations to allow species to diversify usually occur towards the end of development, and are constrained by natural selection, which results in your observation that body structures in related species follow a similar pattern. So dogs are dog-like and apes are ape-like.
But that also means the differences between humans and chimps are minor because they occur towards the end of development, so my example of the skull, where the timing of gene expression changes the ratio of cranium to jaw size; or your example of limbs, where gene expression determines how far a limb bud is extended into a leg and eventually the length of toes. After all, this is not much different than what differentiates a gorilla from a gibbon.

You aren't thinking and here is more hilarious stuff about your refusal to think about what I'm saying. The specific differences you so readily acknowledge for Bulldog and Whippet are equal or more than between human and chimp. The basic structure is similar in the sense I was talking about it ... Just as they don't matter in my frame of reference which I would think would be obvious from the fact that I was clearly referring to the minor differences in size, length, etc. between human and chimp. The basic shape is the same. Actually considering what I said would help. Agreed, that's why I've been pointing out your hilarious position of human and chimp being different regarding such features.Think about it.EnjoyEdited by RAZD, : .

You aren't getting it and obviously don't care, and neither do I any more.