As a Christian I disagree. Science pertains to physical creation, God’s creation, and is the only epistemology which does so, therefore Christians should respect it as a means of understanding God through His creation. Also I think there is ample evidence (theological and biblical in addition to scientific) in opposition to a rigidly, physically literal interpretation of the creation accounts of Genesis. I think this quote from Augustine is pertinent: “ We must be on our guard against giving interpretations that are hazardous or opposed to science, and so exposing the Word of God to the ridicule of unbelievers.” Augustine also wrote a commentary on Genesis in which he hypothesized based on the wording of God’s creative commands (I think it was “let the Earth bring forth” birds, beats etc.) that animals could be created through earthly means, in other words evolution is not contrary to scripture.
Now agreed we shouldn’t derail this thread, but it’s not often I see a Christian interested in nature and science, so if you want to create a pertinent thread or just pm me I would be very interested.
I think iNat forum is Not a place for religious discussions.
This is essentially just how a taxonomy based on evolutionary relationships works as well. The successful phylogenetic hypothesis is always the one which requires the fewest assumptions (the number of assumptions here being the number of apomorphies required for it to work).
Granted, DNA analysis has changed this somewhat as now we have additional arguments to account for, but there is still always some morphological aspect in the definition of any given species, no matter how small a detail that might be. (This is the case at least in zoology, I don’t know how the botanists do it)
I think having an objective (at least in an ideal world) guideline for our taxonomy is good. Otherwise there’d constantly be arguments about where to put what organism, as scientist a may have looked more at traits 1, 2, and 3, whereas scientist b thinks traits 4, 5, and 6 are more important.
I concede that it can make taxonomy less intuitive for non-biologists. However, if the alternative is that no two papers agree on where to place a certain organism, I think it is the lesser nuisance. (Though as I will have to work with papers and already do, I might be biased)
Early mammalian ancestors resembled modern reptiles more closely than modern mammals. There hadn’t been a reduction in the “lower” ribs yet, if I remember correctly, so movement was likely like that of a lizard too, which probably has impacted a lot of the other traits.
There has been a recent paper in which they redid the original “primodial soup” experiment (I have no idea what its actual name was). They found that formation of proto-cells was pretty quick to happen. They in turn served as reaction compartments independent of their surroundings, so a lot of the building blocks of life form pretty easily. I think the most difficult thing to evolve are successful replication and translation & transcription mechanisms. But I’m not too familiar with all this biochemistry and molecular stuff… I’ll link to the paper after dinner… :P
Oh no I agree. To get the thread back on topic I think the final conclusion to be drawn on the subject based on current science is that yes, birds are reptiles. The thing with taxonomy is that it’s focus is evolutionary lineages, so categorization based on anatomy is secondary and must take evolution into account.
I totally agree! The subtopic here involved noting that although some arguments against evolution are astonishingly ignorant and/or stupid (e.g. the feathers/scales thing), others are sufficiently complex and/or the evidence is so hard to get that disagreeing about them is not evidence of stupidity or generalized ignorance. If one concludes that life could not originate on earth without supernatural interference one is mistaken, in my strong opinion, but not (necessarily) stupid. Even intelligent, informed people are wrong sometimes, a hypothesis strongly supported by my 10,000 withdrawn identifications on iNaturalist.
FWIW, I found this article by David Barash in the Nautilus mag site recently that does a great job of addressing the biggest popular misconceptions of evolution, based on his experience as an evolutionary biologist AND as a university lecturer of many decades:
https://nautil.us/10-misconceptions-about-evolution-1183733/
And, I would argue, even some young-earth creationists aren’t unreasonable or denying obvious facts. There’s a huge range of opinions and attitudes even among them.
Yes, they are.
They’re not descendants of dinosaurs, they ARE dinosaurs, just a very highly specialized group of dinosaurs. It’s like if a meteorite hit earth and killed all mammals except bats: the bats would of course remain mammals, but if aliens visited the planet and found bones of extinct mammals they might have a hard time believing blue whale and elephant belonged to the same group as the small flying bats.
Similarly we might have had an easier time seeing birds as reptiles & dinosaurs if some other group of dinosaurs had also survived, or accept that the birds closest living relatives are the crocodiles if some of the land-living bipedal crocs had made it to the present. Though that might have caused other problems.
I meant things that can be observed in living specimens (hypothetical situation here). If you encountered a living, non-mammalian synapsid, how would you, without killing it, tell it apart from a reptile? The jaw articulation could work, when you observe that it chews its food. Anything else?
All living (and extinct) synapsids are mammals, so there aren’t non-mammalian synapsids. Some of the more frustrating things to identify are those for which the only described recognition traits are bone-based. For some lizard families it’s the shape of the interclavical bone that is distinguishing. For some snake families it’s whether the cranial crest is on the parietal bone or not. Neither of these is very helpful when limited to a single picture. When I write notes to myself on identifying it’s always those traits I am likely to see from the angle of most photos even if I have to do a study on those organisms to find the identifying traits. So while endothermy might not be a trait useful for identifying because body temperature is hard to assess from photos, I would probably rely mostly on the lack of scalation for identifying extant mammals so as to account for thing like naked mole rats, which rarely have noticeable fur.
I don’t think we’re on the same page. I was referring to:
I’ll rephrase my original question: If you encountered a living early mammalian ancestor that resembled a modern reptile more closely than a modern mammal, how would you, without killng it, tell it apart from a reptile?
How could we possibly answer this having never encountered a living, Carboniferous-period synapsid? Fossilized bones are mostly what we have to work with.
What exactly is the point to this line of questioning? Evolution occurs on a gradient. There is no one point, no one individual, when one thing becomes another. Again, you are taking a framework built primarily for extant organisms and trying to make it fit in a way it isn’t meant to for long-extinct organisms.
I can respect that point of view, although I would contend that 6-day creationism doesn’t reject science, but rather follows a different interpretation of scientific evidence than that which is considered “consensus.” While I don’t hold to it myself, theistic evolution is certainly more plausible than atheistic/purely chance-driven evolution. Robert Marks was one of my professors in grad school, he is an extremely intelligent and insightful guy and proponent of theistic evolution/old-earth creationism. He has a book called Introduction to Evolutionary Informatics that I have read, which makes a convincing case that undirected/atheistic macroevolution is not possible, by applying Shannon information theory (a field he is very well versed in) to biology
Ah, yes, an electrical engineer (at Baylor, no less). Not exactly what I’d call a first rank biologist.
You alluded to it a couple sentences later:
Which is what I am trying to say about the premise of this thread. I don’t find the titular question to be any more comprehensible than what I am asking you. A reptilian (dinosaurian) lineage develops warm blood and feathers, and at some point, we decide to call its descendants birds. With mammals, the reverse; the lineage that would eventually develop hair and lactation, we decide to call mammals even before that happens – even while they may have been indistinguishable in the field from reptiles. I don’t understand why we have had several threads belaboring the birds/reptiles question when, as you said, the framework was built primarily for extant organisms.
This question is obviously of vital importance to someone or it wouldn’t come up over and over again, but will it materially change the ways we study extant organisms? Will it cause the journal Copeia to start accepting ornithology papers or The Wilson Bulletin to start accepting herpetology papers? As I showed with a screen shot several posts back (post 35), iNaturalist used to have a Taxon “Reptiles and Avians – Class Sauropsida,” but no longer does. Presumably, it was not considered relevant to the extant organisms that iNaturalist is primarily concerned with.
Again,
Does this really matter? Again, I don’t know; maybe not as long as we recognize and acknowledge it as paraphyletic. But bringing mammals into the discussion is like bringing baseball stats into a conversation about basketball, they just don’t apply.
As swampster said, this question is unanswerable, since we only have bones. We’ve never encountered a live individual.
However, since every branching on the evolutionary tree occurs within a species, any two sister taxa are incredibly similar “right after the split” (a split is of course no event that suddenly happens, and rather is a lengthy process, but for the purpose of this thread it’s easier to think of it as punctual). The change then happens slowly and causes a decrease in similarity the more time has passed since the speciation.
I disagree that this is always the case. maybe in some high-profile examples this happens, such as some of the vertebrate divisions being discussed in this topic, but in no way applies to all or even the majority of groups.
one thing that’s useful about molecular evidence is that it’s less contingent — the analytical methods used to produce phylogenies will vary, but the actual characters used to classify organisms are far less arbitrary: we all share the same genetic code. (if you want to talk about classifications that don’t rely on any cladograms, even phenetic ones — that is, ones relying on morphology agnostic of genetics — that’s just a different version of the same problem of using arbitrary characters.)
take something like powdery mildews, a subject I know a bit about. older classifications used coarse and often differing interpretations of key features like the appendages on the fruiting bodies, the shape of spores, and the physical placement of the fungal growth (mycelium). some classifications such as E.S. Salmon’s reduced the entire family to only a few species that had variable appearances and infected enormous diversities of host plants; it made it sort of simple to identify those broadly defined species, but it was incoherent at the level of host preference (always a key feature for parasitic organisms) and even for morphological features that happened to not be the ones Salmon picked. fast-forward 1.2 centuries, and molecular data led to the redefinition of most powdery mildew species that also happened to be morphologically coherent and have restricted host ranges. the actual evolution of them showed that there are key features that define the different tribes and species — genetic data was a guide to this, as well as a kick in the pants to re-evaluate the older oversimplified assumptions.
is it the case that older morphological classifications never changed and improved? not at all. but I can’t stress enough the importance of having a genetic code shared across all life, whereas morphological characters are often incredibly specific to a group. paleontologists struggle with this inherent problem to this day, and while there are clever ways to produce phyletic classifications with morphological data, the modern era of taxonomy has far larger of a toolset at its disposal.
I’ve focused here on the “molecular data” part but there’s much more that could be said on this. my last word for now would be — there’s often more than one classification scheme that can “make sense”. but the real world doesn’t have to instantly fit our intuition anyway.
wdYm by that? You say I’m wrong but then you say that birds are descended from dinosaurs? Are you saying that reptiles are not descended from dinosaurs because…they branched off before dinosaurs? And your language - “older”, “same age” - it sounds like you’re saying they lived at the same time. Do you mean that turtles have not evolved from their dinosaur ancestors, which is odd. And “evolved” at certain times? I think you mean they branched off - they never stopped (or started) evolving iiuc. So I’m not sure what to make of your “isn’t the case”.
I agree that there is no frame of reference with which to answer the question about how to identify something primarily known from bone morphology. I like to imagine there would have been traits to distinguish synapsids from sauropsids, but for so many things it’s only elapsed time that eventually leads to distinguishable traits. I also agree the question are birds reptiles is a bit like trying to determine if raisins are still grapes. They are, but have been modified so much as to warrant their own special name.
Incidentally, (and way off topic), but the journal Copeia doesn’t exist anymore. It was renamed Ichthyology and Herpetology because the American Society of Ichthyologists and Herpetologists no longer wanted their journal named in honor of Cope. Was it the blatant racism, misogyny, or anti-scientific behavior during the bone wars? Take your pick.