Re: Endosymbiosis

Stephen Jones (sjones@iinet.net.au)
Tue, 27 Feb 96 20:25:15 EST

Tim

On Sat, 24 Feb 1996 15:15:51 -0800 you wrote:

AC>Mitochondria have about as much in common with bacteria as apples
>do with
>oranges. They both are round fruits, they are about the same size, they
>both have DNA/RNA Protein schemes that are similar, They both have many
>genes that bear "remarkable similarity", they have histone proteins that
>are identical in amino acid sequence, they both grow on trees, they both
>can be found in the stomachs of much larger bipedal organisms....

I thank Art for this. One of the problems for creationists evaluating
the evidence for creation/evolution is that almost all the
evidence is provided by evolutionists, as Johnson points out:

"Whether God took a short or a long time to create and to what extent
he employed secondary causes as a mechanism are subjects on which
lively debates among creationists should be expected. Disagreements
are particularly to be expected because we all have to work with data
that have been provided by metaphysical naturalists, and we have to
decide how to remove the layers of naturalistic interpretation to
uncover the facts that could have been interpreted differently."
(Johnson P.E., in Moreland J.P. (ed.), "The Creation Hypothesis:
Scientific Evidence for an Intelligent Designer", InterVarsity Press:
Downers Grove Ill., 1994, p8)

Art's shows that the same data can be validly viewed from a
different perspective.

TI>FWIW - I really do not expect a bacterial enodsymbiont that has
>been passed down in isolation from other bacteria and in intimate
>contact with its eukaryotic host for billions of years would look
>exactly like the bacterial group from where it came. I think it is
>fortunate that we can recognize it as being bacterially derived, not
>just that it does not fit with the rest of the eukaryotic sequences.

Here is an interesting example of the evolutionary paradigm.
Similarities are due to evolution and differences are due to
evolution! :-) If organelle and bacteria can diverge over billions of
years from their presumed common bacterium ancestor, why could it not
with equal justice be argued by creationists that both organelle and
bacteria started off with *different* ancestors and over billions of
years have *converged* to where they now in some respects resemble
each other?

After all, convergence is now being recognised as a very common
feature of the living world:

"In the case of phylogenetic analysis, the use of parsimony is based
on the assumption that most characters evolved only once and that
convergence is rare. Surprisingly, supporters of this doctrine have
never tested this assumption. In contrast, biologists working with
both modern and extinct groups argue that convergence is very common
(Cain, 1982; Carroll 1982). Arguments for the close relationship of
groups based only on the common presence of derived features are of
little value, if convergence is equally or more common than the unique
origin of derived characters." (Carroll, R.L., "Vertebrate
paleontology and evolution", W. H. Freeman & Co: New York, 1988,
pp7-8)

Arthur Koestler points out in a section headed "The Doppelgangers"
that some animals are amazingly alike, yet are only distantly related:

"The last phenomenon to be mentioned in this context is an enigma
wrapped in a puzzle. The enigma concerns the marsupials -the class of
pouched animals living in Australia. The puzzle is that evolutionists
refuse to see the enigma. Nearly all mammalians are either marsupials
or placentals. (The 'nearly' refers to the near-extinct monotremes,
such as the duck-billed platypus, a kind of living fossil which lays
eggs as reptiles do, but suckles its young.) The marsupials could be
called the poor relatives of us 'normal', that is, placental, mammals;
they have evolved along a parallel branch of the evolutionary tree.
The marsupial embryo, while in the womb, receives hardly any
nourishment from its mother. It is born in a very immature state of
development, and is reared in an elastic pouch, or bag of skin, on the
mother's belly. A newborn kangaroo is really a half-finished job
about an inch long, naked, blind, with hindlegs that are no more than
embryonic buds. One might speculate whether the human infant, more
developed but still helpless at birth, would be better off in a
maternal pouch than in a cot; and also whether this would increase its
oedipal inclinations. But whether the marsupial's method of
reproduction is better or worse than the placental's, the point is
that it is fundamentally different. The two lines split up at the
very beginning of mammalian evolution, in the Age of Reptiles, and
have evolved separately, out of some small mouse-like common ancestral
creature, over some hundred and fifty million years. The enigma is,
why so many species produced by the independent evolutionary line of
the marsupials are so startlingly similar to placentals. It is almost
as if two artists who had never met, never heard of each other, and
never had the same model, had painted a parallel series of nearly
identical portraits." (Koestler A., "The Ghost in the Machine",
Arkana: London, 1967, p143)

As a Progressive Creationist, I do not rule out that eukaryotic
organelles may have had a common bacterial ancestor - an Intelligent
Designer could have used pre-existing genetic material to create a new
vertical step in the order of life. But neither do I accept
uncritically evolutionary "just-so" stories which assume evolution
in order to prove evolution. If naturalistic evolution is simply
assumed apriori to be a fact, then by definition the *only* theories
that may be proposed to explain endosymbiosis *must* be naturalistic
evolutionary ones. Therefore they will all, to a greater or lesser
extent, "prove" naturalistic evolution.

[...]

Regards.

Stephen

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