mechanism for evolution (was kinds)

Glenn Morton (
Tue, 11 Nov 1997 07:35:03 -0600

Hi Karen,

At 09:41 PM 11/10/97 -0600, Karen G. Jensen wrote:

>>What exactly is supposed to increase here? One could say that each species
>>was supposed to increase its population, or one could interpret that as
>>meaning that the TYPES of birds were supposed to increase in number.
>That is an interesting possibility. Maybe it means both increase in number
>and explore all possible variations.
>>Now before you rule this latter interpretation out because it is
>>inconsistent with the traditional interpretation of scripture, I would like
>>to point out that the traditional interpretation of scripture was generated
>>at a time prior to the consideration of evolution. So to rule out this
>>interpretation on that grounds begs the question.
>The idea of evolution was considered long before Darwin. Before Erasmus
>Darwin. Before Buffon, Bonnet, De Maupertis and other 18th century French
>philosophers, and before the Ionian Greek writings they were studying....
>even before Moses wrote Genesis. But that's another subject.

You are correct, but evolution was not an influential part of theology until
after Darwin.

>>I would also like to note that when Genesis 1:28 says,
>>Genesis 1:28 (NIV) God blessed them and said to them, "Be fruitful and
>>increase in number; fill the earth and subdue it.
>>That it too can be interpreted in the above manner. There have been at
>>least 3 different types of men on the earth, Homo erectus, Homo sapiens
>>neanderthalensis and Homo sapiens sapiens. One could throw int Homo
>>Heidelbergensis if they wanted. And the first man to subdue the old world
>>was Homo erectus who lived from Africa to Europe to SE Asia by 1.6 million
>>years ago. H. erectus crossed the ocean 700,000+ years ago
>Surely man has increased in number(!) and also has blossomed in many
>Your point is that as you see it the Bible does not rule out the change of
>one morphological type to another. And present day populations and
>biogeography do show that types change through time. Fossil assemblages
>also show variation.

Exactly. The Bible does not rule it out.

>So you entertain the idea of infinite change by natural processes -- inert
>to living, reptile to mammal, animal to man. Is this what the Bible says?
>Is this what nature data really says? Actually, only by _extension_ of
>the observable changes can infinite change look plausible.

I am going to suggest a way to explain both your limits to breeding and how
evolution can get around those limits. I have never posted this before, so
I will expect some well deserved criticism. I sent this to a friend earlier.

I came to think this way back when I was studying nonlinear iterative
systems (which is what life is--each generation is an iteration) I have not
had this view properly criticised by those in the know so here is the chance
to watch an idea get smashed.

Morphology is determined by at least two genetic systems. There is the
genetic program for the developing embryo. This is controlled by the HOX
genes. But then there is a more subtle effect of the genetic alleles of the
various traits. The HOX genes control the entire developmental program.
They are the master switches. Gilbert writes:

"How, then, can one modify one Bauplan to create another Bauplan? The
first way would be to modify the earliest stages of development. According to
von Baer, animals of different species but of the same genus diverge very late
in development. The more divergent the species are from one another, the
earlier one can distinguish their embryos. Thus, embryos of the snow goose
are indistinguishable from those of the blue goose until the very last stages.
However, snow goose development diverges from chick embryos a bit earlier, and
goose embryos can be distinguished from lizard embryos at even earlier stages.
It appears then, that mutations that create new Bauplan could do so by
altering the earliest stages of development."~Scott F. Gilbert,Developmental
Biology (Sunderland, Mass.: Sinauer Associates, Inc., 1991),p. 831-832

Gould adds

"If embryology is a hierarchical system with surprizingly few master switches
at high levels, then we might draw an evolutionary message after all. If
genetic programs were beanbags of independent genes,each responsible for
building a single part of the body, then evolution would have to occur slowly
and sequentially as thousands of parts achieved their independent
modifications. But genetic programs are hierarchies of master switches, and
small genetic changes that happen to affect the switches, might engender
cascading effects throughout the body. Homeotic mutants teach us that small
genetic changes can affect the switches and produce remarkable changes in an
adult fly. Major evolutionary transitions may be instigated (although not
finished all at once as hopeful monster enthusiasts argue) by small genetic
changes that translate into fundamentally altered bodies. If classical
Darwinian gradualism is now under attack in evolutionary circles, the
hierarchical structure of genetic programs forms a powerful argument for the
critics."Stephen J. Gould, Helpful Monsters," _Hen's Teeth and Horse's Toes_,
1984, Penguin,p196

And Gilbert finishes

"Thus when we say that the contemporary one-toed horse evolved from a
five-toed ancestor, we are saying that hereditable changes occurred in the
differentiation of limb mesoderm into chondrocytes during embryogenesis in
the horse lineage. In this perspective, evolution is the result of
hereditary changes affecting development. This is the case whether the
mutation is one that changes the reptilian embryo into a bird or one that
changes the color of Drosophila eyes."~Scott F. Gilbert, Developmental
Biology (Sunderland: Sinauer Assoc. Inc., 1991), p. 841

I would suggest that it is the HOX genes that control what creationists call
macroevolution. Micro-evolution is controlled merely by a reshuffling of
the alleles. To get a chihuahua you use the Dog hox master switches but
apply it to alleles for short, ugly, yipping and stupid. (apologies to
chihuahua lovers). To get a St. Bernard, you use the Dog hox master
switches but apply it to alleles for BIG, barking and alcoholic.

Thus when people think they have hit the limit for change, what they have
hit is the limit of change by merely reshuffling the alleles. Further
change occurs by mutation to the HOX genes--the master switches during

I will await proper chastisement by the biologists.


Foundation, Fall and Flood