Evolutionary Transitions

Ridiculous! The transition from reptile to mammal is well understood with many transitional fossils.
See this article from the talkorigins archive.

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Those so-called transitions do not cover the change in metabolism. There is no halfway house between thermionic and exothermionic. A creature is one or the other, and each has defining and unique features that need to exist to function. It is an all-or-nothing change that is beyond the scope of the understood Evolutionary process.

Richard

You might want to read up on that at Wikipedia. Turns out there is.

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Apart from the validity of Wiki. The notion of warm-blooded dinosaurs proves nothing other than a recent change of heart about what constitutes a dinosaur. I am talking about the “invention” of each type of metabolism which starts with fish runs through Amphibeams and then diverges wildly at reptiles and mammals. Each type has unique skin structure and circulation, amongst other things.

Basic anatomy and physiology do not sit well with TOE.

Richard

Given there is a range of adaptations what would you purpose as the “wall” that prevents the gradual evolution of warm blooded animals?

That is not even wrong.

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Since both had a common ancestor at some point there surely was a time before the criteria for reptiles and mammals was what we know today. Go back far enough and no living creature would meet the modern criteria for being a reptile or a mammal. But all of those earlier creatures had what was necessary to exist in the environmental conditions of its times.

I’d assumed that the lineage leading to modern reptiles would have been cold blooded and that warm blooded mammals would have evolved from them. But if it turns out there have been warm blooded species amongst the reptiles or their forebears I wouldn’t find that too shocking. Goes with the territory of not being omniscient.

That is just an assumption. And it is not even a universal one. If you look at the makeup of a mammal you will find that its components are inter-dependent, likewise the reptile or any other so-called “class” of animal. Perhaps you would like a single ancestor for all? if so what sort of physiology would it have?
Historically TOE ran an ancestral line from Amoeba to human via fish, amphibian, & reptile. But, mostly due to the problems I have raised, this has been changed so that the ancestors become less and less defined to try and allow for the complexities of the higher groups to develop in parallel. Monotremes and marsupials have been looked at as primeval mammals but their basic physiology is still fully developed, it is only really the placenta that is developing and that is really a minor thing in the global view.
The problem with talking about complexity is that it has been hijacked by certain pseudo-scientific groups and argued beyond their understanding. Suffice it to say, where vever you try and develop a complex physiology you reach a point where too many things have to change at once to reach the next stage. The epidermis being a prime example. The mammalian skin is essential for its metabolism and superfluous for a reptile. evolution cannot pre-emptively design. Any change must have an advantage in the present not the future. And any redundancy cannot be put on hold until it becomes useful again. WHich is why the idea of feathers being initially for display is so ludicrous. A feather has one basic function: for flight. It cannot be made for something else and then suddenly be re-invented. Not unless there is some sort of constructive outside (designing) force. TOE does not have that force.(without God)
Richard

I forget – what do you believe about the antiquity of the earth and the universe?

Not true. 

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Let’s say I am not YEC.

Richard

What about the raptorial ‘arms’ of praying mantises? These are legs, developed as legs, and are used as legs when the insect moves. However, over time the Coxa, femora and tibia became elongated, reinforced, and lined with spines to enable it to catch and hold prey. So much modification has happened that when the mantis is not moving or is waiting in ambush these modified legs are held up close to the underside of the prothorax like folded arms.

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I get that for many common decent is hard to see in vertebrates and I can understand that. personally, I find it is clear as day in insects were the same basic body plan has been modified and adapted to fill almost every niche on the planet (hyperbole).

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Are you kidding? Feathers are used for sexual display and insulation in living birds. And some birds are flightless despite having feathers, such as penguins. Many dinosaurs clearly had feathers. There is no reason to suppose that feathers on flightless dinosaurs were not used for sexual display/insulation. Sometimes we can even know the color of the feathers. Here’s a video: New Dinosaur Research: Microraptor’s Feather Color Revealed

(Mark Norell always looks like he just got out of bed)

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True that. Even in flying birds, only a few specialized feathers are used for flight, the majority being used for other purposes.
Now, feathers on angel wings, that bothers me.

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So why did other creatures muscle in? Where did they come from? How could they get established? It took a cataclysm to wipe out the dinosaurs (so say) so what happened to the insects? Why the urge to leave the water in the 1st place? How could Nature know it needed to develop into so-called higher creatures? Where is Homo Superior?( Neither Hitler or Stalin succeeded in making one.) probably 99% of mutations in babies are deadly and people think such a process could create me? (without God)
Richard

Because insects represent a huge store of protein that is wide spread and easy to consume.

Insects are incredibly resilient and their relatively short lives (compared to vertebrates) mean that they can recover their populations much faster. The average clutch of a large dinosaur is what 4-9? The average clutch of a cockroaches 200-400. A dinosaur may take several years to become able to reproduce, under the correct conditions it would take a cockroach a few months.

Nature doesn’t know anything; it just is and does. In the same what that gravity or the carbon cycle doesn’t know anything. And the the idea that evolution is pushing to ‘higher’ forms is a misnomer. Evolution is about what works, not about iterating towards perfection.

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Yeah, I watched that TV program. The one that tried to convince me a hinged jaw was an ossified front of a gill.
I was talking about the primary function of a feather. If you have them then they can diversify in function. Penguins and Ostriches are exceptions, and higher up the Evolutionary chain, within its parameters. With a few minor exceptions, feathers are a prerequisite of flight. Like I said earlier. TOE cannot design, nor prepare, nor build. To suggest that feathers were created without flight in mind is absolutely ridiculous. Besides the structure of an avine is also a prerequisite of bird flight, so which came 1st? The feather or the light bone? And why didn’t any other creature get a light bone? Or feathered wings? Or a gizzard? Super strong sternum? Hyper efficient metabolism. Do you think they could fly with a diaphragm?
If you look at Nature there are parameters for each creature that only partially overlap. Much is class-specific. And for some strange reason creatures such as Unicorns, Pegassi, Griffins, even Dragons do not exist. Why? If Creation was so haphazard and flukey they would. (probably)
Richard

Actually, it is estimated that there are 100-200 mutations per generation when dna is passed on from parents to child, the overwhelming majority of which are neutral. A rare few are deleterious, a rare few are beneficial.

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That is exactly my point TOE is development and improvement and at times building. It breaks its own rules to achieve what it is trying to. It starts with the result and fits together a way for it to happen. And it will take any convolution or connection as proof.
Richard

If subject to selection, true. Aside from incidental drift, biologists would not fundamentally dispute this, so it is a bit of a straw man.

Epistasis - adaptations which follow from other successful adaptations - is well recognized and established. So it would be expected from evolutionary principles that particular features of reptiles and mammals would work as part of the whole. The pattern of SARS-19-cov variants has demonstrated that independent mutations are selected which would not have been favored except for the presence of other mutations.

Feathers derive from scales, which do not have flight as a basic function. Warmth and display are easily selectable traits.

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