>I have a possible hypothesis for CP evolution. Suppose, as some noted
>scientists do, that humankind has reached a high level of civilization many
>times only to be destroyed by nuclear war.
Who are these "scientists", and what kind of evidence do they purport to
have? Where is the fossil or other record? Sounds a bit like that utter
nonsense that a major US television network spewed forth a few weeks ago
with that famous "science expert" Carleton Heston as the host--- I could go
on here, but the anti-science and anti-evolution flavor of such stuff just
aggravates the you-know-what out of me, and since it's Friday, I'd rather
not get aggravated so I can enjoy the weekend. So - no flames here please.
It's just my opinion as one biologist who is trying desparately to educate
a bunch of university students. I get really fed up with having to compete
with tabloid press pseudoscience all the time. I'm willing to entertain
new ideas, but I need some hard evidence based on good scientific technique
and principles.
Suppose then, that the earth was
>devastated each time. Plants, with the help of radiation, would be forced
>to adapt to a barren, destroyed world with poor levels of nitrogen, and thus
>have to trap insects for food.
If the radiation was so bad, why didn't it zap the plants and insects as
well ? We'll ignore the apparent immortality of cockroaches for the moment
;-)
With the help of radiation, causing
>unnatural gene mutation, many different plants could have rapidly evolved
>into CPs.
Again, if the radiation was intense enough to kill off most life... As
Wayne Forrester points out, mutations happen all the time, and mutagens
such as radiation are not required (although they do speed up the rate at
which mutations occur). Mutations are necessary for evolution to occur;
they are the ultimate source of all the variations that lead to
evolutionary changes.
> Even if no nuclear wars took place, astronmical phenomena could
>have irradiated the world with irridium, wiping out the dinosaurs, and
>causing extensive plant mutation.
I don't think anyone has implied that iridium was the cause of the demise
of the dinosaurs. It is merely a rather rare earth element that seems to
be associated with meteorites and also in the ejecta from volcanic
eruptions (I'm sure Barry can fill us in with more details). Its abundance
has therefore been used as one piece of evidence to support the possibility
of a large impact at the time coinciding with the extinction event. The
impact scenario essentially says that the dust clouds stirred up by the
impact blocked sunlight and interfered with photosynthesis thus causing the
collapse of local food chains as well as large scale climate changes. The
impact hypothesis is not universally accepted, and a number of alternative
reasons for the five mass extinction events have been proposed. I don't
know of any that have excessive radiation as the cause.
After Hiroshima, many local plants came back as bizarre mutations. This
>would explain VFTs and their cousins. If you look at VFTs, they remind you
>a lot of dandelions. Is it possible that VFTs actually evolved from a
>dandelion type of plant cousin?
>
>---Steve
I don't see the similarity.
I'll shut up now and get back to work,
Liane Cochran-Stafira