From an evolutionary point of view a significant event is when you have the
occurence of a new phylum. The arrival of the phylum chordata is one such
event. Take for example the alligator. It is a species that forms a large,
almost continuous population. And as a species it has not changed much for
millions of years, perhaps unchanged over the last 90 million years. The
term phylum is the noun derivative of phyletic...so we as ethcists are
concerned not primarily with what evolution provides in terms of a single
species, but rather with what conditions provide for the optimum quality of
the widespread and diverse forms of ecosystems that exist...for various
personal and impersonal reasons. The massive rate of species extinctions
caused by humans was not intentional, but accidental. We need to realize
this....

If some relatively recent flowering plants (eg orchids) have evolved, then
the question remains, what would the chances be, given extensive continental
scale anthropogenic subclimaxes displacing major functional units and groups
of species within large ecosystems, on continued capacity for specialization
and adaptation of phyla? What happens when 99% of the Grassland biome in
North America is displaced by irrigated genetically modified corn, potatoes,
wheat and soybean?


The ancestors of all existing terrestrial chordates is very small in number.
The terrestrial chordates (animals with backbones) originated from only
seven species, all of which have a hip that is similar in structure...so
what happens when the earth is completed converted to anthropogenic
subclimaxes dominated by less than twenty weak and sickly human designed and
engineered cultivars?

That should not be hard to answer ....

best regards

john foster

Also..
> Phyla
> do not evolve, only species evolve. Why would Grant call his/her book
> "Organismic Evoluion" and then make such a claim? Maybe you had better go
> back and read that section.

I know that, but in the beginning there is one ancestor to a phyletic line.
There has to be one organism that sets foot on land...before there are
others. That text I cannot find...I misplaced it but will retrieve it today
most likely....





>
> (cut)
> JF wrote:
> Well. I should clarify. After all I was only quoting Grant, from
"Organismic
> Evolution"; I attempted to claim that the only (or most) significant
change
> on an evolutionary scale during the last 90 million years was the
evolution
> of flowering plants, angiosperms. This is just an opinion. Certainly there
> are some other changes but these others I believe are due to flowering
> plants becoming dominant in many ecosystems. Certainly the existence of
> glaciations wroughts change but glaciations began 140 million years or so
> ago, and are only one component of environmental change, and does not have
a
> direct permanent effect on ecosystems, nor species, unless they are forced
> to adapt or perish. Climate may influence evolution because in a gradual
> changing environment many species may be able to adapt, especially if
there
> is a polymorphic gene pool.
>
> (cut)
>
> Bissell here; Just a question to JF. When you use the term "phyletic" what
> are your refering to?
>
> JF wrote:
> The item that interests me from a moral perspective is the myriad phyletic
> lineages that adapt to and exploit new ecological niches.