In your note on REAL HISTORY of January 17 you wrote, in response to Jan
DeKoning's earlier note:
"The power of the theory of evolution lies in its ability to provide a
framework for the actual history of the earth and the life forms thereon. No
evolutionist would talk about the transition from fish to amphibian as an
allegorical account of tetrapod origins. This transition actually happened.
The lack of such a REAL HISTORY for Christian views leaves us in a less
powerful position.
"I can point to a set of rocks which contains the fossil forms, I can tell
you
about the similarities in the fossils from fish to tetrapod, the fact that
panderichthyid fish lost all but four fins under their bodies, had lungs and
gills, had the humerus, ulna and radius in the forelimb and femur, tibia and
fibula in the hindlimb. The earliest tetrapods had the same, lungs and gills
except the fins were now fitted at the end with up to 8 "fingers". But their
legs could not support their weight and did not have full motion. They had
half evolved legs. The skulls of fish and amphibian were nearly identical.
The
transition is quite fascinating. AND IT WAS REAL HISTORY.
"Too often Christians write books which tell the reader why evolution can't
be
true. But the author's are so happy to tell us what is wrong with evolution,
they forget to give a framework within which to explain the data. They forget
that just because evolution is wrong, it does not mean that Christians are
correct. And they fail to give a REAL HISTORY of what did happen. Try to
find
in Darwin on Trial how the sequence from fish to tetrapod took place (Did God
create every link [5 or 6 links] separately?); why the tetrapods appear in
the record when it did, just after arachnids and snails on land appear
(evolutionists say the tetrapods were attracted by the food; what is the
anti-evolutionist to say?). They don't tell me why they are right, how to
fit
the data into their metaphysical view. To them the data is irrelevant and
thus
divorce the Christian view from earth history."
I would like to respond to your scenario about the transition from fish to
tetrapod as an evolutionary phenomenon. In general it looks convincing. But
I would like to ask some questions about some of the particulars, if I may.
(BTW I am neither a YEC nor an anti-evolutionist. I just do not believe
that Darwinian mechanisms can account for major innovations in the history of
life, such as the transition from aquatic to terrestraial life, although they
do explain minor variations that add to the adaption of the innovations to
the new environment.)
1. First, I assume that you mean *natural selection* when you refer to,
*evolution* and not just some vague notion of *change*. (If my assumption is
not correct please let me know. I believe it is necessary to agree on what
we mean by *evolution* to have a productive discussion.) Natural selection
means that a number of random mutations must have taken place in the germ
line of the panderichthyid fish in order for it to take the very first steps
toward becoming a tetrapod. Let's take the mutations that resulted in the
"the humerus, ulna and radius in the forelimb and femur, tibia and fibula in
the hindlimb." Why would the initial mutation that started this transition
from fins to legs have ever occurred and been selected in the first place?
It would only have interfered with the adaptation of the fish to its aquatic
environment, wouldn't it? Since natural selection has no plan or purpose for
the future, such a mutation would seem to be useless even detrimental when it
first appeared. If this is true, would it not have been eliminated from the
gene pool immediately?
2. I assume that the panderichthyid fish was better adapted to its aquatic
environment before the beginning of its transition to a being a tetrapod than
it was in its initial move to land. Why, then, did it not stay put where it
was, rather than migrating to a new environment for which it was not
initially as well adapted? Land is a more difficult environment than the
ocean, as J. Z. Young says (The Life of Vertebrates, pp. 14-16). Even if
there were swamps and pools to help the fish to make the transition, it
probably remains true that their current adaptation to the ocean was easier
than their initial adaptation to any new environment. You refer to
evolutionists as saying: "evolutionists say the tetrapods were attracted by
the food." Is that true? If so, how do they know it's true? What food?
Arachnids and snails? What evidence is there that food on land was more
plentiful and better than food in the ocean. In sum, how does natural
selection explain the migration from an easier environment to which the fish
was well-adapted to a more difficult one?
3. This is all part of a more general problem that Mivart posed during
Darwin's day, as you know: How does natural selection account for incipient
stages of useful structures? To use your example, how do you account for the
incipient leges between the time that panderichthyid had fins and the time
they became full-fleged legs? Gould says Mivart's question has never been
answered. Do you agree?
4. How would a non-Darwinian like me try to explain the transition you
described? That's a tough question. I too, like you, want a larger,
historical context. In fact, I want a cosmic one. I believe the universe
was created by God for the final purpose of bringing into existence human
beings on earth (and possibly on other earths, maybe in alternate forms),
whose purpose, to paraphrase the Westminster catechism, is "to know God and
enjoy Him forever." The Big Bang, all the cosmological constants, the large
number coincidences, the origin of life, the transition from aquatic to
terrestrial life, the parade of vertebrates leading to and culminating in
human beings, are all driven by that purpose. It is very difficult for me to
use Darwinian evolution as a large explanatory framework because of its
avowed purposelessness and materialism. I do not find it possible to explain
the transition of fish to terrestrial life in an evolutionary, purposeless,
materialistic framework which I believe Darwinian evolution is. How do you
deal with this unabashed purposelessness and materialistic naturalism of
Darwinian evolution?
5. To explain the transition from aquatic to terrestrial life in
non-Darwinian terms, I would use principles of development, expanded to
include the development of large groups of animals as well as individuals. I
find developmental principles, more compatible than Darwinian mechanisms for
dealing with the transition you described, and other changes in the fossil
record. For me principles of development apply to changes in the great
animal phyla as well as to individual organisms. Development has several
critical characteristics that make it a better candidate than evolution for
explaining transitions and other phenomena in the fossil record. It is
*end-directed* and *purposive* as Mayr noted; the goal is the sexually mature
adult. It is *internally driven* largely by genetic instructions. That is,
it is largely *autonomous from the environment*. It is *hierarchically
organized,* as von Baer asserted long ago (1828), with the general
structures, most common to the phylum to which the organism belongs,
appearing first in embryogenesis, and more specific structures appearing
later and emerging from the general structures. The germline posseses
developmental programs; that are expressed over time in the offspring of the
phylum. The individual genome is inherited from the germline, thus forming a
*seamless genetic connection* with the history of the phyletic lineage.
Individual development provides a window of phyletic developmment. As much
if not more change in the biological world comes about by evolution than by
Darwinian mechanisms. In development the *form* of an organism appears
before its *function or behavior.* In this view the *form* and *structure of
legs* in the panderichthyid fish developed first, followed later by its
*function* of terrestrial behavior.
6. I hold then that the transition from aquatic to terrestrial life of
fishes was driven by developmental processes. Evolution may have fine-tuned
the process toward the end of the transition, but did not initiate it.
Underlying the entire transition is the fundamental driving purpose of the
universe, the appearance of human beings created to be in joyful relationship
to their Creator.
I would appreciate any comments anyone may have on this developmental
perspective.
Bob DeHaan