Dinosaur Lung to Bird Lung Evolution

That depends on a lot of this discussion that’s been going on. I’m going to have to investigate the idea that dinos had avian-style unidirectional lungs. Not all scientists seem to agree on that point.

I think that would be the safest bet. Looking at it from the other direction, I don’t see how anyone can confidently state that non-avian theropod dinosaurs had tidal lungs.

There does seem to be a much stronger consensus around non-avian dinosaurs having feathers. To be charitable, we could throw that in the same bin as flow-through lungs for the time being.

So what else does that really leave us with as far as complete redesigns? We have vertebrae, birds lost their tails, a modified wisbone and pelvis, rib cage, same type of skull, the same leg and arm bones . . . I’m not seeing a total redesign here. I am seeing a modified dinosaur. In the same way, bats look like modified mammals. In both cases, two lineages adapted to flight found different fitness peaks which is the earlier discussion that moved us towards dinos and birds.

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You might look up some of the references in the Wikipedia article for a start.

News to me. What?

Well, it’s a broad topic. Basically it boils down to the question, do all alleged transitions present themselves as gradual stepwise chains, or do we see giant leaps of total and complete change? I think the Cambrian Explosion is the greatest evidence of “total redesigns” we could realistically hope for. But the whole fossil record is full of examples of great changes with no evidence of transitions between. So much so that Gould incorporated that into his basic understanding of how evolution works. Of course, I’ve never seen how punctuated equilibrium could make any sort of plausible sense at all from a genetic point of view. The genetics could only ever support gradualism in the best case scenario.

You would have to dig up every fossil in the ground to make that determination, and you would also have to demonstrate that you have a fossil for every transitional species that existed.

Darwin already did a great job of explaining how it works.

Gould and Eldredge described Punk Eek in some of the same language. They fleshed it out more with concepts of species range, peripatric speciation, and so on, but Darwin had already discussed the basics of it.

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Darwin knew exactly nothing about how it (allegedly might) work. He had no knowledge of genetics at all, or even of basic cell biology.

Obviously he is referring to Darwin’s comments on patterns in the fossil record here and not genetics…

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Wrong. Punk eek was not developed because of a lack of transitions. It was developed based on positive fossil evidence. Mainly Gastropods and trilobites. It is also has nothing to do with saltations. It also isn’t mutually exclusive of gradualism.

“It [PE] represents no departure from Darwinian mechanisms.” (Gould and Eldredge 1977, Section IV, “PE as the basis for a Theory of Macroevolution”, page 139)“

And of course the famous one:

“Since we proposed punctuated equilibria to explain trends, it is infuriating to be quoted again and again by creationists - whether through design or stupidity, I do not know - as admitting that the fossil record includes no transitional forms. Transitional forms are generally lacking at the species level, but they are abundant between larger groups.” (Gould 1983)

But what I was talking about was genetics in that particular place, so that would make the response off-topic.

I don’t know what could make you say any of these wrong things. Gould’s concept of P.E. was very much informed by the awareness of a lack of transitions:

‘The extreme rarity of transitional forms in the fossil record persists as the trade secret of paleontology. The evolutionary trees that adorn our textbooks have data only at the tips and nodes of their branches … in any local area, a species does not arise gradually by the gradual transformation of its ancestors; it appears all at once and “fully formed"’

Stephen Jay Gould, Evolution’s erratic pace, Natural History 86 (5):14, May 1977

Gould believed his idea was able to make sense of this pattern, but he developed his ideas long before we had much understanding of genetics, and before the introduction of neutral theory. I have no idea how they could possibly fit together. P.E. requires rapid bursts of greatly increased complexity, totally changed bodyplans, etc. Evolutionary genetics struggles to make sense of how it could manage to happen even gradually.

I don’t know where you get your misinformation from, but you should find better sources. This is all wrong. Gould understood his theory required saltations, and he believed environmental changes and changes of niche would make sense of that. But that’s a just-so story like all the others.

You can read the quote for yourself. It’s a given that no evolutionist enjoys being quoted by creationists. Heck, you can even read the title of his article and get a good idea of what he’s talking about. (By the way, I have searched in vain online to try to find a full-text copy of this article. I’d love to read the whole thing.)

It [PE] represents no departure from Darwinian mechanisms.” (Gould and Eldredge 1977, Section IV, “PE as the basis for a Theory of Macroevolution”, page 139)“

Now show me a quote where Gould said PE relied on saltation

Let me guess? You are about quote his hopeful monsters paper. Even though the words PE were never mentioned and the paper was about Goldshmidt and not PE

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I guess Gould was misinformed about what Gould thought…

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Darwinian mechanisms… i.e. mutation and natural selection.

What is a saltation? What is an “erratic pace”? Why did he title his article “Evolution’s Erratic Pace”?

I very much want to find that article online and I can only find where it has been quoted (almost always by creationists of course). I’d love to read the entire thing in context.

You need to read 72’ 77’ And then Structure. I Worship Gould. I have read and own every thing he has ever written. Listen, we are all wrong about things sometimes. You are wrong here. Very wrong. So I really suggest you read the first two papers atleast. Especially 77’. Because it contains pages discussing the positive evidence PE was built on.

If you really want to understand punk eek you need to read the real literature and not his Natural History column (which was great)

Also, you are a YEC and you have told
Me that you accept a limited, separate common ancestry. So you believe species arise from other species by microevolutionary processes. PE was mainly hypothesized to address species to species transitions.

“PE is a model for discontinuous tempos of change at one biological level only: the process of speciation and the deployment of species in geological time.” (Gould and Eldredge 1977, p. 145)

It’s something you should be open to. Because it would apply in your creation model.

From Structure:

“The theory asserts no novel claim about modes or mechanisms of speciation; punctuated equilibrium merely takes a standard microevolutionary model and elucidates its expected expression when properly scaled onto geological time. (p. 778)”

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Here’s Gould’s testimony in the 1980 Arkansas creationism trial:
http://www.antievolution.org/projects/mclean/mva_tt_p_gould.html

Q Would you please briefly explain the theory of punctuated equilibrium?

A The theory of punctuated equilibrium, which is an attempt to explain gaps as the normal workings of the evolutionary process, begins by making a distinction between two modes of evolution. First, evolution might occur by the wholesale or entire transformation of one’s form, one’s species into another.

We maintain in the theory of punctuated equilibrium that that is, in fact, not a common mode of evolution, but what normally happens, the usual way for evolutionary change to occur, is by a process called speciation or branching. That it’s not the whole transformation of one entire species into another, out a process of branching, whereby one form splits off. In other words, a small group of creatures may become isolated geographically from the parental population, and then, under this small isolated area, undergo a process of accumulation of genetic changes to produce a new species.

A process of accumulation of genetic changes to produce a new species. Accumulation sounds to me like a build-up. A gradual build-up. Not an instantaneous or “saltational” build up. Not all at once.

It goes on with some elaborations. Later:

Q Professor Gould, how does creation science deal with the theory of punctuated equilibrium?

A From the literature I’ve read, it’s been very badly distorted in two ways. First, it’s been claimed that punctuated equilibrium is a theory of truly sudden saltation, that is, jump to a new form of life in a single generation. That is a kind of fantasy.

The theory of punctuated equilibrium doesn’t say that. It merely says that the correct geological representation of speciation in tens of thousands of years will be geologically instantaneous origin.

The second distortion is to claim that under punctuated equilibrium we argue that entire evolutionary sequences can be produced in single steps. In the transition from reptile to mammal or from amphibian to reptile might be accomplished under punctuated equilibrium in a single step. That’s manifestly false.

The punctuations in punctuated equilibrium are in much smaller scale record the origin of new species. And we certainly believe that in the origin of mammals from reptiles that many, many steps of speciation were necessary.

Again, as I said, it’s like climbing a staircase. But believers and those who advocate the theory of punctuated equilibrium would never claim mammals arose from reptiles

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A (Continuing) in a single step. And yet that is how it’s often depicted in the creation science literature. Can I give an example?

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Ok, let’s not do that!

I’m open to that possibility. I’ll read Evolution’s Erratic Pace for myself when I can, and I’ll try to see what he’s really saying.

Sure, this is very helpful. I welcome the clarification.

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Ha! He was also a baseball man like myself.

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Nothing Darwin wrote on the subject required knowledge of modern genetics or cell biology. Populations at the edge of a species range can be exposed to different selective pressures causing those populations to evolve in a different direction than the larger population. The populations that evolved at the edge of the species range can then replace the larger population, and in the fossil record this would look like a sudden change.

Gould and Eldredge were able to couch this in terms of genetics, where new variations take longer to fix in a larger population. However, new variations can reach fixation much more quickly in a small population.

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Yes, we should consider that a swim bladder with lunglike functions as a lung, at some point. Still, if we’re talking about independent evolutions of a lung, we shouldn’t think of evolution of a lung from a swim bladder that itself evolved from a lung as quite the same thing as the evolution of the original lung.

There are some. Can we at least agree that birds are not a good example of such a lack of transitions? What legitimate examples are you now thinking of?

Not relevant, since punctuated evolution has nothing to do with major transitions.

Complete nonsense. 1972??

You understand nothing of punk eek. You should consider reading (I assume for the first time) the original paper: Eldredge N., Gould S.J. Punctuated equilibria: an alternative to phyletic gradualism. In: Schopf T.J.M. editor. Models of Paleobiology, 1972. p. 82-115.

Gould was interested in saltation, but that’s a completely separate idea from punk eek.

@T_aquaticus, do you think @PDPrice has anything interesting about whales?

Is a whale a severely corrupted Mammal? Or is a whale an amazingly adjusted mammal that can swim and hunt more deeply than many fish?

An example would be the reassortment of genome segments in influenza virus.

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