Glenn rebutted>>>
>Technically speaking this is no longer true. Last December, Nature
reported the discovery of a new phylum. ....This phylum lives a happy life
on lobster lips.
>Since this phylum is not found in the Cambrian explosion, and indeed is
not found in the fossil record at all, it leaves open the possibility that
this is a Holocene evolved phylum. For those who believe in progressive
creation, does this mean that God has been busy creating new phylums
recently?
To which I must question ;-^) , how many fossilized lobster lips were in
the Burgess shale, and how many have been examined anyway???
Of course, to the experts in the field, the following comments will
establish my credentials as close to zero, but it may help clarify the
subject for some others.
Seems to me there can be a lot of odd & quirkly phylums that have survived
for millions of years in obscurity, and never quite show up in the fossil
record. Prehaps, in a couple of decades unambiguous evidence of the phylum
will be found in ancient deposits, and then a whole host of other fossil
features (say, on trilobite lips) will be understood as being of this
phylum.
Under the top-down hypothesis, it is entirely possible for new phylum to
arise, it is just much more difficult. To a degree, as biological systems
(and the same can be said for engineered systems) become more complex, they
become both more robust (better able to exploit their environment) and more
fragile (unable to withstand alterations in either themselves or the
environment).
At the dawn of life, life was primitive, based on a relatively small number
of genes. A couple of mutations could induce a wildly different body plan
with a high chance of survival (compared to today).
If that body plan was superior in some aspect (or in some niche), the line
would thrive (if only in a ecological niche). If that body plan was barely
survivable, the line might survive until subsequent survivable mutations
rendered it superior, or until it found a niche in which the new body plan
was more efficient.
On the other hand, modern ecological niches are full of highly competitive
and specialized species. Consequently, if a new body plan is barely
survivable, it will probably be eaten before it finds it's niche, or, when
it find's it niche, will be starved out by an more efficient species
already there.
One sees a similar scenario in industry & technology. When an industry
begins, obviously diverse designs florish. When some designs are
demonstrated to be superior in the market, they take over the market, and
innovation goes on at a more subtle level.
Early cars had drastically different designs, and each innovation could
cause noticable difference in apperance and handling; now cars all
essentially look the same, and drive similarly, and most innovations are
vitually invisible.
In short, early life was simple and innovation consisted of widely varying
body plans. They survived and adapted. Later life is more complex and
efficient; much of the diversity of early body plans is preserved, but
innovation is much more biochemical in nature, and body plan variation is
incremental.
Grace & peace,
Dennis Sweitzer