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Author: pineapple.linkpineapple.link Date: Nov 15, 2007 14:00
Hello,
New to this newsgroup, so bear with me.
I've done due diligence as far as trying to find an answer to this
question (google searches, various FAQs, even a college library), but
couldn't, so at any rate please forgive me if this is some old
question...
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Author: Tim TylerTim Tyler Date: Nov 16, 2007 12:20
> Now, let's take a prehistoric caterpillar
> which currently does not undergo this sort of metamorphosis at all,
> but through some mutation just acquires the very first step in the
> chain - the ability to transform its body into a gelatinous mass and
> die (it "dies" because it has not yet evolved the ability to further
> transform itself into a butterfly - that's further down the
> evolutionary chain). What is the evolutionary benefit that is being
> realized at this point in time from turning into goo and dying (there
> needs to be a benefit for natural selection to "select for" this
> ability)?
There isn't one. The "transform its body into a gelatinous
mass" step was not a first step, but an end-product.
No doubt the ancestors of butterflies did not undergo such a
radical transformation - and could not fly. They probably
just grew legs and genitals: fairly orthodox developmental
steps that do not involve self-liquefaction.
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Author: pineapple.linkpineapple.link Date: Nov 17, 2007 23:09
On Nov 17, 3:20 am, Tim Tyler cyberspace.org> wrote:
> The "transform its body into a gelatinous
> mass" step was not a first step, but an end-product.
Could you explain?
> No doubt the ancestors of butterflies did not undergo such a
> radical transformation - and could not fly. They probably
> just grew legs and genitals: fairly orthodox developmental
> steps that do not involve self-liquefaction.
If my memory of biology serves me correctly, the butterfly is not
simply a caterpillar with wings, legs, genitals, etc. It is an
entirely new, different creature built "from scratch." You could
essentially consider it a whole new species, a whole new animal. If
this is correct, explain the above comments in light of this?
Thanks.
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Author: LorentzLorentz Date: Nov 17, 2007 23:09
On Nov 16, 3:20 pm, Tim Tyler cyberspace.org> wrote:> pineapple.l...@ yahoo.com wrote:
>
> No doubt the ancestors of butterflies did not undergo such a
> radical transformation - and could not fly. They probably
> just grew legs and genitals: fairly orthodox developmental
> steps that do not involve self-liquefaction.
> I think the modern consensus is that the common ancestors of all
winged insects could fly, but could not do the metamorphosis.
Evidence?
There are many winged insects that can fly but do not undergo a
total metamorphosis. Such insects include locusts, cockroaches (yes,
there are winged and flying species of cockroaches) and termites.
Further evidence?
Some of the winged insects that are extant and do not do a total
metamorphosis have fossil precursors that precede the fossils of flies
of winged insects. The fossils of winged beetles and termites far
precede those of insects that undergo total metamorphosis.
Further evidence? All insects that undergo total metamorphosis ...
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Author: Perplexed in PeoriaPerplexed in Peoria Date: Nov 19, 2007 22:35
> On Nov 16, 3:20 pm, Tim Tyler cyberspace.org> wrote:>> pineapple.l...@ yahoo.com wrote:
>>
>> No doubt the ancestors of butterflies did not undergo such a
>> radical transformation - and could not fly. They probably
>> just grew legs and genitals: fairly orthodox developmental
>> steps that do not involve self-liquefaction.
>> > I think the modern consensus is that the common ancestors of all
> winged insects could fly, but could not do the metamorphosis.
> Evidence?
> There are many winged insects that can fly but do not undergo a
> total metamorphosis. Such insects include locusts, cockroaches (yes,
> there are winged and flying species of cockroaches) and termites.
> Further evidence?
> Some of the winged insects that are extant and do not do a total
> metamorphosis have fossil precursors that precede the fossils of flies
> of winged insects. The fossils of winged beetles and termites far
> precede those of insects that undergo total metamorphosis. ...
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Author: Tim TylerTim Tyler Date: Nov 19, 2007 22:35
> I have asked to assume that, in the past, there were only
> the first two stages (caterpillar, death/liquefaction),
> and we want to somehow add the third - butterfly.
That's the problem, right there. You are assuming that
phylogeny followed the same temporal sequence as modern
ontogeny. That's not necessarily what happens.
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Author: Paul CiszekPaul Ciszek Date: Nov 20, 2007 10:37
In article darwin.ediacara.org>,
Lorentz yahoo.com> wrote:> I forgot the more recent references where this was stated. But for
>fun, read Darwin carefully. He was a little wrong on the origin of
>metamorphosis. However, he stated that the law of ontogeny and
>recapitulation was wrong in the case of insect larva.
Didn't Darwin also suggest the possibility that the wings of insects
were adapted gills? That idea seems to have its modern adherants as
well.
--
Please reply to: | "One of the hardest parts of my job is to
pciszek at panix dot com | connect Iraq to the War on Terror."
Autoreply is disabled | -- G. W. Bush, 9/7/2006
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Author: LorentzLorentz Date: Nov 21, 2007 09:39
On Nov 20, 1:37 pm, nos...@ nospam.com (Paul Ciszek) wrote: > In article darwin.ediacara.org>,
>
> Lorentz yahoo.com> wrote:>> I forgot the more recent references where this was stated. But for
>>fun, read Darwin carefully. He was a little wrong on the origin of
>>metamorphosis. However, he stated that the law of ontogeny and
>>recapitulation was wrong in the case of insect larva.
>
> Didn't Darwin also suggest the possibility that the wings of insects
> were adapted gills? That idea seems to have its modern adherants as
> well.
In Origin of the Species, Darwin suggests that the precursor of
metamorphizing insects alternated between sexual and asexual
reproduction. Sort of like jellyfish and aphids. Jellyfish are more
similar...
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Author: LorentzLorentz Date: Nov 21, 2007 09:39
On Nov 18, 2:09 am, pineapple.l...@ yahoo.com wrote: > simply a caterpillar with wings, legs, genitals, etc. It is an
> entirely new, different creature built "from scratch." You could
> essentially consider it a whole new species, a whole new animal. If
> this is correct, explain the above comments in light of this?
>
This is not correct. The caterpillar is not a whole new species, a
whole new animal. Some writers like Gould made that statement, but
they exaggerated slightly.
I was under the same misconception, but some kind person on this
forum corrected me and I checked references. The transformation is
radical, but not so extreme. There is a segment by segment correlation
between the parts of the caterpillar and the parts of an insect
larva.
Do you agree, disagree, feel...
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