Posted: Sep 23, 2018 7:43 pm
by Calilasseia
Wortfish wrote:
Calilasseia wrote:In the meantime, with reference to this assertion:

Wortfish wrote:Evolutionists disingenously like to claim that macroevolution just means speciation.


I'd like to know precisely which observable interactions and phenomena are purportedly being "omitted" or "ignored" by evolutionary biologists with respect to the term "macroevolution". I suspect I won't see a straight answer to this, but who knows, for once I could be mistaken ...


Some evolutionary biologists claim microevolution means change within a species whereas macroevolution means change leading to a new species.


Citation for this?

Wortfish wrote:But such a shallow and cautious definition would mean that nearly all creationists accept macroevolution.


Do tell us all why that definition is "shallow and cautious". Preferably with reference to some actual biology to support this assertion.

Wortfish wrote:However, I think macroevolution really refers to the emergence of new families, orders and phyla as we look back in time.


And here we have a prime example of the follies that creationists routinely indulge in. Which centres upon the fact that they treat the categories of Linnaean taxonomy as decress from on high, that the biosphere must somehow conform to, as opposed to cataloguing categories which humans formulated in order to organise the data and make sense of it.

Indeed, one of the central problems with Linnaean taxonomy, is that its categories are ranked categories, whilst modern phylogenetic analysis recognises that there are no 'ranks' in biology at all. Unfortunately, until someone comes up with a better system than the one Linnaeus provided, we're stuck with using it, warts and all, but no one in modern biology thinks higher-ranked Linnaean taxa are prescriptive. Once again, they're treated as simply descriptive, a distinction that creationists routinely demonstrate an inability to understand. An example of the hilarity that arises from Linnaean taxonomy being ranked, hits taxonomists square in the face the moment one considers tetrapods, which sees the old Linnean classes of Amphibia, Reptilia, Aves and Mammalia now recognised as sub-clades of Tetrapodomorpha, which itself is a subclade of Sarcopterygii, which is itself a SubClass in Linnaean taxonomy (though a phylogenetic revision of the fishes re-establishes Sarcopterygii as a Class). Except that in a ranked taxonomic system, a given taxonomic rank is only supposed to give rise to taxa of lower rank. Matters become even worse when one realises that Reptilia is itself no longer monophyletic (Aves is now properly a sub-taxon of Reptilia, as is Mammalia), and for that matter, whilst all modern amphibians are Lissamphibia, the Class Amphibia includes two extinct SubClasses, one of which was the ancestor of Reptilia.

Indeed, modern data has led to wholesale revision of the old Class Pisces, which is now discarded as a paraphyletic taxon, and fish now have an extensive phylogenetic classification scheme, arising from the large body of work performed by Willi Hennig and others. But that scheme still uses Linnaean nomenclature, simply because nothing better has been devised yet.

Admittedly, Linnaeus didn't have access to modern phylogenetic data, and provided us with a taxonomic scheme that served us very well indeed until the advent of said modern phylogenetic data. But Linnaean taxonomy is clearly a product of its time, one that's being pressed into service for cataloguing purposes until a phylogenetically grounded replacement scheme is devised. Even with those provisos in place, however, Linnaeus himself never intended his classification scheme to be prescriptive, but descriptive, as his surviving correspondence at the University of Uppsala makes clear. Indeed, the mere fact that taxonomists instituted a process of taxonomic revision as far back as the days of Fabricius, in order to reflect better the state of the biological data, on its own points to this, before one delves into Linnaeus' own thoughts. Some organisms have been subject to taxonomic revision to the point where they have over two dozen junior synonyms accompanying the currently accepted valid taxon.

Plus, modern biologists understand that the emergence of groupings that can be classified as phyla, were possible in the distant past, when bauplans were simpler and less specialised. It's somewhat harder for such a major departure to arise from a modern, much more specialised and derived basis, though not, I suspect, impossible.

Quite simply, the higher taxonomic divisions, are divisions humans formulated for their cataloguing convenience, and at bottom, nothing more. Though I'm familiar with the manner in which not only creationists, but other religious fundamentalists, have a habit of treating words in a book as somehow magically dictating to reality how it behaves, regardless of whether or not reality pisses itself laughing at such hubris.

Moving on ...

Wortfish wrote:
Not all of them. I remember dealing over at TalkRational with one Ray Martinez, who asserted that species were fixed and immutable. Though I note with interest, that when pressed on the matter of what form this 'magic barrier' to speciation took, he was typically evasive in standard creationist manner. I also had much fun parading a range of fancy goldfish before him, in order to demonstrate that his "species are fixed and immutable" assertion was horseshit.


Ken Ham and AiG accept and embrace speciation.


Do they? Should I care about this? Or should I, more properly, be suspicious of their trying to force-fit biological data into a doctrinal framework, for the purpose of propping up pre-scientific mythology?

Wortfish wrote:
Oh, you mean the made up shit they conjured up, to try and avoid having 2½ million species crowded into a wooden barge?


The "Kinds" diversified and speciated from a common ancestor of the particular kind. There was a dog-kind, cat-kind, worm-kind etc.


Er, do come back when creationists have something other than a morass of comedy fabrications, with respect to the matter of defining "kind" ... which none of them have been able to do.

Wortfish wrote:
Care to provide a definition of "created kinds"? Only I've yet to see a creationist who could do this successfully. For example, Jonathan Sarfati waded in on this one, with the following piece of hilarity

Based on the Biblical criterion for kinds, creationists deduce that as long as two creatures can hybridize with true fertilization, the two creatures are (i.e. descended from) the same kind. Also, if two creatures can hybridize with the same third creature, they are all members of the same kind. The hybridization criterion is a valid operational definition, which could in principle enable researchers to list all the kinds. The implication is one-way—hybridization is evidence that they are the same kind, but it does not necessarily follow that if hybridization cannot occur then they are not members of the same kind (failure to hybridize could be due to degenerative mutations). After all, there are couples who can’t have children, and we don’t classify them as a different species, let alone a different kind.


So, Sarfati asserts above that [1] organisms that can interbreed are purportedly of the same "kind", but then goes on to assert that [2] er, organisms that can't interbreed could also be of the same "kind". Which leads most of us who paid attention in class, reaching for this image in response:

Image



Zebras and horses are of the same "kind". It is possible for them to interbreed but not with sterile offspring.


Care to rework that last sentence into something resmbling conventionally parseable English?

Of course, if you're trying to assert here, that being able to produce offspring, sterile or not, is a diagnostic criterion for "kind", then you have a problem, because there are documented instances of closely related species that will not produce offspring of any sort if you hybridise them. Indeed, I've alighted upon an example of an organism that uses sex as a biological weapon to eliminate food competitors, that provides a prime example of this. Hesperocimex cochimiensis and Hesperocimex sonorensis are two species of Hemipteran bugs, that compete for a food source - they're blood feeding parasites of owls in their natural habitat. It's been found that if a male H. cochimiensis inseminates a female H. sonorensis, the result is that the H. sonorensis female dies from a massive immune reaction to the H. cochimiensis sperm. Just to add to the fun inolved, like numerous other Cimicid bugs, these species aso indulge in hypodermic insemination, which adds its own spice to the proceedings.

Bit difficult to produce offspring, if the female's response to insemination is to curl up and die as if she's been hit with a nerve gas attack. :)

Another fun example from the world of invertebrate zoology, is provided by Skipper butterflies (Family Hesperiidae). Members of the Genus Erynnis have been documented for some time as possessing asymmetric genitalia, making them stand out from the majority of other Lepidoptera, in which the genitalia are bilaterally symmetric. However, two American species in the Genus, Erynnis funeralis and Erynnis propertius, have secondarily re-acquired symmetry in their genitalia, which means they're now mechanically incompatible for hybridisation with other members of the Genus in their locality.

I really love the way biology repeatedly pisses all over creationist pretensions ... :D