Tuesday, February 20, 2018
 

Steve and Scott Discuss ’Guided Common Descent’

Is 'guided gradualistic common descent' reasonable, scientifically?

  • 6 November 2017
  • Author: Scott Cherry
  • Number of views: 232
  • 2 Comments

by Steve Schlichter and Scott Cherry

Is 'guided gradualistic common descent' reasonable, scientifically?

You may review the original facebook discussion here: http://bit.ly/2h7MRUq.

Steve,

Please forgive my delayed response to your five claims just over a week ago. As I said they deserved careful consideration. Plus, I needed to do some homework, which I hope you will deem a virtue, not a vice. Now, with your approval I have made a new post from our ongoing Facebook discussion that started about a month ago in this group (with now close to 200 comments between us, and including some other contributors such as Kathy Leach and George). For anyone out there just noticing this for the first time, or rejoining us after losing interest, we wanted to put our discussion on your radar and at your fingertips again. But to prevent a really long fb post only part of my response is in it. The rest is here. In fact Steve, you can write responses directly into the blog under mine if you want. But don't feel obligated to respond to everything.

 

In subsequent volleys I recommend that we focus the discussion even more, say, on just one of the five claims, or a related one, or just one sphere or topic, or one limited argument. Otherwise you will find yourself putting in 6-8 hours of homework too, and I would spare you that. I myself prefer not to do it again. 

 

For the sake of any readers, our subject is 'evolution' for lack of a simpler term (forgive me, Steve). It might better be called the question of guided evolution (small 'e', not Neo/Darwinian), or naturalistic creation, or gradualism, or gradualistic common descent, or even something else I made up: guided macro natural selection. Steve and I have had trouble nailing down the preferred term so I have come to call it < >.  That's the one Steve espouses. The alternative that I espouse is what I have decided to call "Immediate Vocal Creation" or "special creation' which I hope needs no further explanation, except to say it is the opposite of gradualism. But presently our discussion is not about the Bible or theology, nor about the age of the earth.

 

The question before us is, "Is < > reasonable, scientifically?" Steve's position is 'yes' and mine is 'no'.  If you want to review the whole discussion you can see Steve's original post on 10/19 here: http://bit.ly/2h7MRUq.

 

Steve, when I first saw your post on 10/28 with your five claims for < > I quickly noted the the point about the alleged 'evolution' of whales from a terrestrial wolf-like animal. Then I remembered seeing the debut of a video on that very subject at the 2015 National Apologetics Conference. It's called "Living Waters" by Illustra Media. The video is not online but I ordered the DVD, and I received it last Wednesday. Only the last segment is actually about the science of this claim but it is very well done and illuminating (20mins) from which I will quote a bit later.  


On 10/30 Steve wrote (red)

“Ok, so, we have looked at observational evidence and seen adaptions in progress. We know that adaptations occur and now we can discuss what limits it has.

 

I will focus on the example of cetaceans because a) it has a lot of data and b) it proves the point well. i.e. It is hard to argue that a whale is 'kind' of coyote. It is only an example and there are thousands of similar studies.

 

Biologists tell us that cetaceans are all related and descended from a 4-legged land animal.

 

Comparative anatomy tells us:

 

1) They have placentas, give live birth, and feed their young using milk like other mammals. They are warm-blooded and have lungs. They have blow-holes but their skulls have two opening, like land mammals into their nasal cavity. They also have vestiges of hair, like mammals. So, on the surface there are similarities but one could think they just have the same designer - a re-used template so to speak.

 

2) On closer look, we see whales have arm, wrist, hand, and finger bones underneath their front flippers. Same set of bones that bats, hippos, and humans have. They do not have back legs but they do have a strange un-used set of bones that appear to be hip (complete with ball and socket joint), thigh, and shin bones.

 

So, comparing their anatomy, we do have many similarities. They are not like any other creatures that live in the water and they have strange similarities with land animals.”



Scott's Response:

Similarities between animals do not prove evolution/common ancestry, either 'guided' or 'unguided'. They may appear to suggest it if one presupposes or allows for it, but they do not prove it. There is a prevailing 'philosophy' of similarities within the system of evolution ('guided' or 'unguided') that showcases them as evidence for such, but it is just that. In this philosophy, 'Common ancestry' is presupposed a priori and acts as a lens through which the similarities are viewed.


I believe my previous quote from Stephen Meyer--on its own terms--strongly contributes to this stage of the discussion again: Is summary, it is improbable [certainly not proved] that micro-mutations do not produce macro body-plan changes, wherever the line between them is said to be. (Facebook thread, 10/29 at 9:14pm) I have pasted here again for your consideration:

"The Origin of Biological Information and the Higher Taxonomical Categories": "...Mutations will be much more likely to be deadly if they disrupt a functionally deeply embedded structure such as a spinal column than if they affect more isolated anatomical features such as fingers. ...J.F. McDonald notes that genes that are observed to vary within natural populations do not lead to major adaptive changes, while genes that could cause major changes--the very stuff of macroevolution--apparently do not vary. In other words, mutations of the kind that macroevolution doesn't need do occur, but those that it does need (namely, beneficial body plan mutations early in development) apparently don't occur. Yet there is no evidence from developmental genetics that the kind of variations required by neo-Darwinism--namely, favorable body plan mutations--ever occur." (Stephen C. Meyer, Darwin's Nemesis, p. 188) 


 

There are other possible reasons for similarities and numerous analogies that could be discussed involving the presence of similarities that need not and should not indicate common descent. Humans and ducks also have similarities but no one talks about their common ancestor. I realize that's a ridiculous example, and it's supposed to be. But it is a fact: We are both bi-pedal, etc. At the other extreme, legless lizards ("glass lizards") are so similar to a snake that it is easily mistaken for one at first glance, but they are classified separately because of eyelids and external ears. They have really obvious similarities but their differences are deemed more distinguishing. 

 

Regarding the descent of whales from wolves or coyotes, this is where the above-mentioned video segment comes in again: https://vimeo.com/241409002. The most salient points are made by Evolutionary Biologist Dr. Richard Sternberg when he says, first, that the coming together of the number of adaptations necessary for this fete of evolution to take place is "unfathomably complex".  The narrator adds, "The scale of these adaptations would have to be massive". Next Sternberg adds, "Think of all the parameters that would have to be modified and multiply that by a thousand-fold or more. That's the scale of this problem. ..."Can you explain it by "some smooth gradualistic textbook scenario--a little change, a little change fixation. No."  Finally he says, "In my opinion you are dealing with a suite of characteristics that had to be integrated from the get-go." Later in the longer segment Sternberg also explains the virtual mathematical impossibility of this particular piece of evolution within the allowable timeframe (in old-earth terms): https://vimeo.com/241409586.



3) When looking at the embryos of dolphins, there are also strange similarities during development. They have two nostrils, like a dog would have in the beginning but then they move to the top of the head during development. They have arm buds (or fin buds) that develop into fins but they also have leg buds, like land mammals that fade away. Why do they develop in a way so similar to land animals?

 

See previous comment.

 

As I mentioned before, Phillip Johnson has given us an excellent work entitled, Darwin on Trial. In it he cites Douglas Futuyma as follows: 'How does God's plan for humans and sharks require them to have almost identical embryos?' To this Johnson replies, "The features Futuyma cites may exist because a Creator employed them for some inscrutable purpose; or they may reflect inheritance from specific common ancestors... The task of science is not to speculate about why God might have done things this way, but to see if a material cause can be established by empirical investigation." (p. 71)


Johnson further states, [Claims based on embryology e.g.] "That embryos actually recapitualte adult ancestral forms--that humans go through fish and reptile stages, for example--was never borne out by the evidence, and embryologists quietly discarded it." (p. 72)


On the next page he connects the dots between embryology and morphology/homology: "Similarity of the pattern in the mature limb should reflect a repetition of ancestral patterns in the developing limb in the embryo. Unfortunately, detailed comparisons...show that this is not the case. ...without conforming to predictions based on the theory of common descent."

 

The point is that, he says, "The similarities of vertebrate limbs resemble analogies more than homologies [i.e. superficial similarities] and as such do NOT support Gould's claim that they are...inherited from a common ancestor...unless we assume a priori that the theory is true." 

 

4) The fossil record shows findings of a slow transition of these traits. Contrary to the constant claims of YEC, we do have an abundance of transitional fossils (this claim is a pet peeve of mine). 

 

No, we do not. See previous comment and additional quotes below:


"'The history of most fossil species includes two features particularly inconsistent with gradualism:

1. Stasis. Most species exhibit no change during their tenure on earth...morphological change is usually limited and directionless.

2. Sudden appearance. In any local area, a species does not arise gradually by the stteady transformation of its ancestors; it appears all at once and 'fully formed'.  (Johnson quoting Stephen J. Gould, p. 50)

 

"In short, if evolution means gradual change of one kind of organism into another kind, the outstanding characteristic of the fossil record is the absence of evidence for evolution." (Johnson, p. 50)


"Species that were once thought to have turned into others turn out to overlap in time with their alleged descendants, and 'the fossil record does not convincingly document a single transition from one species to another.'  In addition, species remain fundamentally unchanged..." (Johnson, p. 51)


"No doubt a certain amount of evolution could ave occurred in such a way that it left no trace in the fossil record, but at some point we need more than ingenious excuses to fill the gaps. The discontinuity between the major groups—phyla, classes, orders—are not only pervasive but in many cases immense.(Johnson, p. 54)

"We have alredy seen that the hypothesis of creative natural selection [his term for < >] ...is discormfirmed by the fossil record." (Johnson, p. 95)

These quotes apply to the case of the Basilosaurus (whales) too. In the Research Notes of Darwin on Trial Johnson asks, "Is it certain that Basilosaurus had shrunken hind limbs, or only certain that fossil foot bones were found reasonably close to Basilosaurus skeletons?" (p. 195)

 

Basilosuarid skull (roughly 30 million years ago) is similar to a modern whale but has nasal passages further down the snout, like land mammals indicating what seems like an intermediate species. Nostrils half- way between land mammals and modern whales. It also has small, but fully developed hind limbs that were far too small for walking on land but much more developed than a modern whale. 


Maiacetus (47.5 million years) is considered a whale but it has fully developed hind legs. It has teeth that matched Basilosaurid and middle ear structures that match both Basilosaurid and modern whales. Basically, it is a walking whale.

 

That line and similarities can be tracked further blurring the line between modern whales and ancient land creatures. I have often (when I was YEC) asked why can't this just be evidence of creatures that have gone extinct that were kind of in-between these species. You may be thinking this.



Refer to the link to the video clip on this subject. But there is much more contrary evidence on this subject.



5) DNA is the most compelling evidence, IMO. Whale DNA has been compared to most other animals and it most closely matches the Hippo indicating a common ancestor (not that whales came from Hippos). Hippos have unique ankles shared with some of the ancient whales fossils discussed. whales and hippos are the only mammals on earth to have internal testicles.

 

That two kinds of animals as disparate as whales and hippos both have internal testicals is insignificant, merely analagous. Again, apparent morpohological homologies are often no more analogies, and either way they are not definitive. Regarding DNA, Stephen Meyer addresses this subject. (I realize he, and Johnson, probably is an advocate of 'guided evolution'/Common Descent, so he is a 'knife that cuts both ways'. But quotes from YEC creation scientists may be dismissed 'out of the gate' by some (tho maybe not Steve).

 

Meyer writes this: 

 

"Major morphological innovations depend on a specificity of arrangement at a much higher level of the organizational hierarchy. A level that DNA alone does not determine. Yet if DNA is not wholly responsible for body plan morphogenesis, then DNA sequences can mutate indefinitely, without regard to realistic probabilistic limits, and still not produce a new body plan." He goes on to say that, in principle, they cannot, including those that arose in the Cambrian explosion. (Darwin's Nemesis, p. 190)
Print
Tags:
Rate this article:
No rating

Scott CherryScott Cherry

Other posts by Scott Cherry

2 comments on article "Steve and Scott Discuss 'Guided Common Descent'"

Steve Schlichter

11/7/2017 4:02 AM

Thanks for the reply Scott.

I guess we will have to come to agreement on terms a little bit. Common descent is a specific term meaning that all life came from a single simple life form. That was not really our discussion as of yet. Our discussion was about the edges of adaptation. We agreed that a species can adapt slowly through minor adaptations to the point where it becomes a new species. You suggested that it does not go further, that an adaptation does not occur beyond species. i.e. That adaptations are limited or blocked at the genus level. So, I am happy with being 'minor adaptations that lead to a new genus or even higher taxonomical levels' or a discussion on 'What are the limits of natural selection". I gave 5 reasons to suggest that adaptations have occurred that resulted in the diversity of an entire phylum; That modern chordates have descended from Cambrian chordates. I argued from the example of cetaceans evolving from ancient land mammals.

I do not believe the Sternberg video addresses the issues very well. He says the changes are hard for him to imagine and need be "unfathomably complex". Citing the mathematical probability is an argument against naturalism (I am not a proponent of naturalism). Creation of animals, whether immediately and vocally, or not, is complex. If the evidence we have makes gradual adaptations the best explanation, then the complexity involved doesn't really matter.

He also does not deal with the fossil record that basically records the changes he is saying are impossible. The adaptations that lead from a nostril to a blowhole are documented in the fossil record. Fossils that share characteristics between the coyote like creature and the whale can be found in multiple sedimentary layers where the nostrils in the skull are slowly migrated up the head. Blowholes are not a single hole in whales. In the skull, they are two holes in the nasal cavity. Descendant of whale-like creatures have these two holes that are further down the snout which seems to suggerst that the blow hole was closer to the front.

None of the other issues from comparative anatomy were addressed. What is the best explanation for the lower hip bones complete with ball and socket joint, thigh, and shin bones in whales? what is the best explanation for the fact that whales have vestigial hair? My argument from embryos does not need to entail whatever theories scientists have for them. My only point was around the bud that appears in whale embryos that appears to be the lower leg assembly. In land mammals, it is the lower leg assembly. Fish do not have this lower bud but whales and other cataceans do. Cetaceans are unique in that they have synamorphies with other mammals (mammary glands, three middle ear bones, etc) but also have similarities with fish. The question is what is the best explanation? Were the original body plans vocally created 400 million years ago but the cetaceans were only vocally spontaneously created 48 million years ago? I do not feel like you are providing an explanation, only refuting one. If you say that adaptations are limited and do not float far from the originals species then where do the newer species come from?

Dr. Myers is arguing for the sudden appearance of body plans during the Cambrian period. The further development of each of those body plans is not really something he is denying. He is only speculating that information is necessary for their appearance. He is not questioning the survival of the fittest, only their arrival. As I mentioned previously (and you seem to agree that his points cut both ways). Stephen Myer would agree that the Cambrian explosion represents the initial body plans (the biological term used to indicate the types of body plans starting at the phylum level) and that those body plans are continued in modern species that share those body plans. There were no whales and no coyotes in the Cambrian period so both whales and coyotes must have adapted from the choredates that did live in the Cambrian or came about by some other means.

One side note. No one is arguing macro-evolution in the sense that some macro change ever occurs. we are talking about the same process that creates a new species. Small adaptations that provide an advantage and are propogated. No single organism is changing nor is any single macro-change occurring. Species A adapts until it is no longer compatible with species A, now it is species B. A sub-set of species B adapts until it is species C, then D, E, F, G, H for millions of years. Now, why would we assume that species H is the same genus as species A? It comes from the same body plan but what would prevent it from drifting away from the genus of species A.

On the fossil record. All I can say here is that raising the question is good. As you quote Johnson doing: "Is it certain that Basilosaurus had shrunken hind limbs, or only certain that fossil foot bones were found reasonably close to Basilosaurus skeletons?" However, you made the claim that there is much more contrary evidence. This is not really contrary evidence. This is just calling a claim into question. My example gave several intermediate species. I agree that we should not assume these are intermediate species but what is the best explanation?

Remember, the question we are dealing with is whether minor adaptations lead to a new genus from a descendant species, not is ALL evolution true. One review of Johnson calls him out for not being able to separate the claims of evolution. Henry Bauer says he "misleads about science and about what science says about evolution." Bauer explained, "Johnson lumps evolutionists together as Darwinists...but Johnson doesn't understand that even Darwin's original 'theory' contains at least five separate concepts that can be held independently. We are discussing natural selection and it's limits not 'Darwinism' and certainly not naturalism.

Since we are referring to outside sources. Here is a quick primer on the specific adaptations that I am arguing seem to exist. (I am not arguing for the wholesale adoptions of all things evolution). https://evolution.berkeley.edu/evolibrary/article/evograms_03 or a video if preferred: https://www.youtube.com/watch?v=lIEoO5KdPvg

The question is this: What is the best explanation based on the evidence we have? We see species adapt into other species. Do we see an edge to this? Some barrier. I do not see any evidence that the processes that we witness occurring that gets us from a Great Dane to a tea cup dog has not been occurring for a very long time and has resulted in great diversity. It is true that whales have unique features and abilities that make them especially suited for their environment. the fact that these are amazing and complex does not really argue against the point that they have evolved. Unique, fitting, and specially equipped is what we would expect to see if minor adaptations lead to a new genus from a descendant species creating unique and specially equipped new species.

Sidenote: I have been thinking about how this discussion applies to Romans 1. How God reveals himself through what is plainly seen and how all are without excuse. This means that the naturalist or the atheist has the ability to reason about nature - to draw conclusions based on what creation reveals. the natural world will not lie to him. Since he is without excuse, it is expected of him.

Here is what I see (and I know you see as well)

Psalms 104:24-25

O LORD, how manifold are your works!

In wisdom have you made them all;

the earth is full of your creatures.

Here is the sea, great and wide,

which teems with creatures innumerable,

living things both small and great.

Job 12:7-10

But ask the beasts, and they will teach you;

the birds of the heavens, and they will tell you;

or the bushes of the earth, and they will teach you;

and the fish of the sea will declare to you.

Who among all these does not know that the hand of the LORD has done this?

In his hand is the life of every living thing and the breath of all mankind.


Perry Boyd II

1/17/2018 12:42 PM

Hello

Leave a comment

Name:
Email:
Comment:
Add comment