Definition of evolution and the distinction between micro/macro


(Chris) #242

We can’t say no attempt to map out original Kinds will ever be successful unless we try. In trying we might find it can’t be done.
“The concept is not based in reality.” Actually it does match observation quite well.

All feline species have inherited the unique Bauplan of cats, and cannot deviate from this commonality as they adapt, each in its own particular way. —Stephen Jay Gould, The Structure of Evolutionary Theory, 2002. ref

Simply dismissing it as “not based in reality” is a faith statement.

A body plan, Bauplan (German plural Baupläne), or ground plan is a set of morphological features common to many members of a phylum of animals.[1] The vertebrate body plan is one of many: invertebrates consist of many phyla.

20 out of the 36 body plans originated in the Cambrian period.


(Matthew Pevarnik) #243

In which case, what should a good scientist do with their model if it provides to not accurately describe reality?

Indeed, this is how nested hierarchies are made that demonstrate common descent- I.e. the law of monophyly:


(Stephen Matheson) #244

I’ve already written about the definitions, and further typing on the topic seems likely to give the impression that this conversation has merit. Instead, why don’t you venture an explanation of why the difference between these terms matters to you. We have already established what the terms mean to scientists and what they mean to various people here.


#245

It appears that male ligers are sterile, so that would be a bit difficult. But for the sake of argument, if there were a population of interbreeding ligers then I would consider them to be a possible species. “Kind” seems to be so ill-defined as to be meaningless. Other examples of arbitrary groupings found in science is genus, order, family, and class.

I think this is the key. I’m not saying that everyone should adopt Gould’s NOMA, but there are parts of that philosophy that might be worth considering. Just as someone who loves science I would hope that people aren’t needlessly scared away from science because of their religious beliefs. We may think that these types of disputes really don’t have any real world consequences, but one has to wonder how many potentially wonderful and productive scientists have been scared away because of their religious beliefs or the perception that only atheists can be scientists.


(Lynn Munter) #246

But it has been tried, repeatedly. You can’t possibly claim that Christianity has known for thousands of years that the animal kingdom is divided into a finite number of specially created ‘kinds’ but nobody in all that time has put time and research into listing them. The only problem is that every attempt has had unsatisfactory results, by which I mean that there is a great deal of uncertainty in trying to establish claims of ‘these animals could have evolved from a common ancestor, but these are too different and they could not have evolved.’

Evolution predicts that no matter if this line is attempted at the level of species or genus or family or order or phylum, there will be borderline cases where no one can be sure what level the distinction should fall at.

Shall we take a look and see this in action?

Caenolestidae (Shrew-opossum kind)
…This order is diagnosed by some finer details of the molars and wrist bones, which do not significantly affect the overall cognitum…
Shrew-opossums are considered here as a separate kind for several reasons. Available pictures of extant species can be distinguished from opossums by head shape and eye size. Since these features are variable within many of the rodent-like marsupials, these criteria could reasonably be challenged. A second reason is that combining them would involve combining two groups that currently occupy the status of order (though previously they had been placed below this). To avoid underestimating Ark kinds, it was decided to list the shrew-opossum as a separate kind.

This statement, “to avoid underestimating Ark Kinds…” appears throughout the paper, whenever the authors appear uncertain if something is a real ‘Kind’ or not. Here are more examples:

Myrmecobiidae (Banded anteater kind)
The banded anteater (Myrmecobius fasciatus), also known as the numbat, is unique among marsupials in that it is diurnal and uses its long tongue to eat termites. It was once classed as a subfamily within Dasyuridae. Apart from its color pattern, it seems to fit in the same cognitum as other dasyurids. Its karyotype (2n = 14) is similar, but this same pattern is seen in other marsupial orders as well. It is distinctive from dasyurids in its serology, though to a degree more commonly found at the subfamily level. Major reasons for placing it in a separate family are distinctive dental and basicranial features (Archer and Kirsch 1977). They are considered a separate kind here because they do have some distinctive features and we have chosen to prefer splitting to lumping, especially above the family level.
…Many of these animals have a rodent-like morphology, making it a challenge to see clear divisions when looking at the live animal without supporting laboratory data. Might this be a hint that the level of the kind may be higher and include several orders of marsupials?..
Burramyidae (Pygmy possum kind)
Despite these shifts, the current family arrangement appears fairly well accepted. There certainly is not the degree of upheaval at the family level seen in bandicoots (order Peramelemorphia). There is, however, still considerable disagreement in how the current families are related to each other (Meredith, Westerman, and Springer 2009; Munemasa et al. 2006). One possible reason for this ambiguity is that the families are not related. However, the frequent use of possum in the common name for species in many of these families betrays the fact that there is a natural cognitum above the family level. Here the kind is tentatively placed at the family level to avoid underestimating the number of kinds on the Ark, but these issues should be looked at in more detail.
Hypsiprymnodontidae (Musky rat-kangaroo kind)
The last three marsupial families are in the suborder Macropodiformes. The name means “big feet” which refers to the elongated hind foot. There is a strong cognitum at this level because of this trait. In addition to being evident in pictures of these animals, it is reflected in the name kangaroo which appears as rat-kangaroo for these first two families, reflecting the smaller size of their members. It would seem far more natural to place the level of the kind here, but I have resisted doing so for several reasons. First, it is at the suborder level, which is already fairly high. This first family is the most unique and also bears some resemblance to other rodent-like marsupials when noticing features such as head shape and overall body proportions. Further, these animals are less familiar to me which would increase the likelihood of me lumping them together inappropriately. For this project, we agreed to prefer splitting to lumping, especially above the family level, to avoid underestimating the Ark kinds.

All these are just in the Marsupials, before we even get to the true mammals! There are more examples but I am afraid I’m belaboring my point.

Also of note is the time they wondered if the marsupial mole might be of a kind with non-marsupial moles because they looked so similar, so they did a genetic comparison test to see but the results showed no similarity. Score one for convergent evolution and evolutionary scientists knowing what they’re talking about.

So I don’t think you ever answered, would you consider this guy part of the ‘Cat Kind’?

Thank you for this clear statement. A body plan is phylum-level. I now understand the position being stated in this quote (the conclusion of your Uncommon Descent FAQ #13):

In the end, the terms are plainly legitimate and meaningful, as they speak to an obvious and real distinction between (a) the population changes that are directly observationally confirmed, “microevolution,” and (b) the major proposed body-plan transformation level changes that are not: “macroevolution.”

Only phyla-level changes are macroevolution, and everything below that is micro-evolution. So all mammals, birds, reptiles, amphibians, fish and sharks could have evolved from something like a lamprey. Given the enormous diversity represented by this unfolding of life, I would not have expected it to be too problematic to imagine the various worm-like phyla also being related to each other, but hey, what do I know. If this is a belief that makes people feel better about God, I suppose it must make sense to them.


(George Brooks) #247

@Lynn_Munter:

What if WHAT is still too complicated?

Genesis 1:24-25 seems virtually as PERFECT a description as someone living more than 2000 years ago could have offered as a description!


(George Brooks) #248

@T_aquaticus,

Here’s a link on that topic:

https://ligers.org/the-breeding-of-ligers.html

“Sterility”
“Commonly, it is believed that all ligers are sterile. The species is formed by the crossbreeding of male lions and female tigresses. Still, it is important to know that while most ligers are sterile, there can be cases in which these animals mate. The most obvious example in this context is the 15-year-old ligeress who gave birth to a healthy li-liger after mating with a lion. The event occurred at a Munich Zoo.”

“In fact about 6 cases of female ligeresses giving birth have been registered until today. The fertility of ligers is low and when a female is not sterile she can only produce one cub at a time. There has never been a cub born by two liger parents and no fertile male liger cases have ever been registered.”

Needless to say… you and I don’t really care about the specifics of the LIGER case. There’s always some other case, more challenging than the one before, coming at us from around the corner.
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Now… on the issue of how to categorize a pride of Ligers, or Tions, or whatever fulfills the example best, I would resist the idea of calling them a NEW species. I think they make an excellent parallel to a Ring Species… but without any ring.


(George Brooks) #249

@Lynn_Munter and @aarceng,

I think the description of Kind in Genesis is more than enough. It doesn’t try to make it into a “higher category”. And it doesn’t try to divide kinds into species or vice versa.

A Kind is something that perpetuates itself… whatever that is. I think Mayr was delighted (or would have been) …


(A.M. Wolfe) #250

You’re probably kicking a dead horse here, Lynn. When we push too hard on the specifics of what a Kind is, our friend here generally says this is not the goal of the thread, which is to discuss definitions of micro- and macroevolution. (Now, why these terms are actually important to him remains an open question since at least post #243.)

I admire his laser-focus (which is rare here on the Forum!), even if I suspect it covers a fair amount of cognitive dissonance and uncertainty about how these things actually work out in practice. That’s ok, we don’t need to prod at that; it’s not polite to do so if he doesn’t want to talk about it.

Just my $0.02. Hope you’re well.


(Chris) #251

AFAIK the first comprehensive attempt was by Linnaeus who began with the idea that species were fixed. He eventually concluded that fixity of species was wrong.

Of course. Remember that the purpose was to get a reasonable upper bound estimate of the Ark Kinds so when in doubt, split.

Since speciation probably occurred before the flood it is likely that there will be fossil specimens that are different to extant species.

But we digress. My purpose in saying this

was to confirm my reasons for not using speciation as a marker for macroevolution and to point out that YECs (most anyway) don’t deny speciation takes place.

There’s a somewhat longer quote on the problem of “species” by physicist Rob Sheldon here.

@AMWolfe is right. Precisely defining the boundaries of a Kind (Baramin) is not the goal of this thread. In any case there is no precise boundary to Species either.

I have already commented on your proposed definitions so I won’t do so again and no one else appears willing to throw their hat into the ring.


(Matthew Pevarnik) #252

The two are completely different situations. In one, you cannot distinguish when one ‘species’ becomes another- much like Old 14th century English transforming into American English today. That is to be expected with common descent. In the other, you can’t figure out what a baramin is supposed to be because of this continuity of species. A baramin must be an absolute grouping that is not, and is clearly not related to any other baramin. There would be clear genetic signatures and clear morphological discontinuities. However, that does not seem to be the case for any species ever.

But at the same time, we are permitting microevolution to exist within a baramin (albeit in a hyper-evolutionary sense) but then saying that macroevolution cannot occur, despite the fact that some of the original baramin are so incredibly closely related that they themselves ought to be grouped in the same baramin. And then, you literally find that everything alive fits into the same baramin and now you accept common descent!


(Chris) #253

Pardon me, you haven’t read my posts properly. I never said that macroevolution cannot occur within a Baramin, or even within a species. In fact one reason to reject speciation as a minimum requirement of macroevolution is that I accept that macroevolution could occur within a species and without speciation.


(Matthew Pevarnik) #254

Okay. So you are saying that-
Macroevolution occurs within species but doesn’t produce speciation? So that would be like saying that an isolated population can accumulate large changes such that it would no longer be able to maybe even reproduce with what it once was but it would still be the same species? And macroevolution can also occur within a Baramin but it too has a sharp limit where the original baramin cannot come about via this macroevolution?

If it didn’t have limits then you have to keep accepting the original kinds also are so incredibly related they constitute their own kind and so on until you agree with common descent.

Or in other words, since blurry lines of ‘species’ is exactly what one would expect with common descent, and the lines are extremely blurry with what constitutes a ‘kind,’ then that indicates that even ‘kinds’ share a common descent. For there to be the spontaneous creation of anything, there would be very clear genetic and morphological markers which are simply not there.


(Lynn Munter) #255

I’m glad we agree on this much, and sorry for digressing too much!

Hang on, you weren’t thinking that the last paragraph I wrote was my proposed definition, were you? That was the creationist position being put forth at Uncommon Descent, as near as I could tell. They are defining macroevolution as “major proposed body-plan transformation level changes,” i.e. vertebrates and other phyla were specially created and then all the modern animal forms we are familiar with today ‘microevolved’ from there.

Granted, the casual reader might not realize that’s what they’re saying, but they did say it.


(George Brooks) #256

Lots of discussion on species, kinds, types, baramin… that doesn’t seem to follow Genesis 1:24-25 at all.


(Chris) #257

No, I was referring to


(Chris) #258

OFFS, No I’m not saying that!

I’m saying that macroevolution does not necessarily cause speciation.
Those who say that speciation=macroevolution are thereby excluding any changes that don’t produce speciation no matter how much functional information or new function is added. So if you think that human adult lactose tolerance has added significant information/function you couldn’t claim it as macroevolution because it hasn’t produced a new species.

On the other hand a population could partition into sub-groups each of which has less genetic information than the original and these could become new species even though they have lost information and not gained any information.


(Chris) #259

Well that’s because of those who want to define macroevolution=speciation.


(Chris) #260

Another digression.

Well you got that wrong, at least if you mean Young Earth Creationists. Uncommon Descent is for the Intelligent Design Community; it says so in their banner. ID is not YEC; it is one thing that the Discovery institute, Creation Ministries, and Answers in Genesis agree on.

ID is actually agnostic, although individual members hold a range of views. You might find a creationist position being put forth at Uncommon Descent in the comments (it might even be me) just as you will here (this time it definitely is me).

Since ID accepts evolution but proposes that it requires infusions of Intelligent Design, i.e. that neo-Darwinian mechanisms are not sufficient, it seems to me to be closer to those versions of theistic evolution that allow for God to direct the course of evolution.

There’s probably a thread on this topic somewhere.


#261

In my experience, this exercise is a bit like Lucy holding the football for Charlie Brown. No matter how many examples we give it will never satisfy your definition of an increase in functional information, especially given the fact that you will probably never give us a functional and measurable definition of functional information.