Researcher Richard Michod and colleagues at the University
of Arizona in Tucson have found that high temperatures make
the green algae Volvox
A news article about the story:
- ttp://www.betterhumans.com/News/news.aspx?articleID=2004-
06-09-3
theory.
I'm less convinced. The study is on a creature that
reproduces
However, plenty of other things cause stress - in
particular, pathogens and a changing environment are both
stressful - and
circumstances in the course of their explanation.
So - it's not easy to interpret the observation that
stress induces
since the competing theories make similar predictions in
this area.
In general, stress might well indicate that your genome is
not working out
- and that some outcrossing might pay off.
However the *reason* for the problem is not
necessarily known -
it /might/ be an accumulation of deleterious mutations
(Michod's theory)
- but it might well also be due to a pathogens successfully
tuning in to it (Hamilton's theory).
This particular organsm probably isn't telling us about
that, though:
some reason (perhaps to generate diversity in the face of
the high selection pressure from the environmental
challenges winter produces), then heat stress might simply
be a means of signalling that - with the details of the form
of the signal being of no consequence.
Organisms - such as aphids - which exhibit facultative
parthenogenesis are indeed useful models with which to
examine the short- and long-term
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