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From: heather@blia.BLI.COM (Heather Mackinnon)
Newsgroups: misc.consumers,sci.bio,sci.misc
Subject: Re: pesticides
Message-ID: <3124@blia.BLI.COM>
Date: Wed, 19-Aug-87 13:44:12 EDT
Article-I.D.: blia.3124
Posted: Wed Aug 19 13:44:12 1987
Date-Received: Sat, 22-Aug-87 04:57:04 EDT
References: <3620@cit-vax.Caltech.Edu> <2207@zeus.TEK.COM> <3102@blia.BLI.COM> <3667@cit-vax.Caltech.Edu>
Organization: Britton Lee, Los Gatos, CA
Lines: 56
Summary: case in point
Xref: mnetor misc.consumers:2519 sci.bio:600 sci.misc:456

In article <3667@cit-vax.Caltech.Edu>, walton@tybalt.caltech.edu (Steve Walton) writes:
> In article <3102@blia.BLI.COM> heather@blia.BLI.COM (Heather Mackinnon) writes:
> 
> >3.  We evolved with the natural insecticides in plants in the levels they
> >    are found in plants.
> 
> But they are still carcinogens, according to laboratory tests.  If the
> fact that we evolved with them was relevant, we should show some
> resistance to their carcinogenic effects; we don't. 
> 
> >    Most experiments on carcinogens show how the chemicals work in isolation.
> 
> Which brings up another interesting point: it seems according to
> recent work that actual cancers are not caused by one agent, but by
> several working in sequence.

A few years ago (I would have to dig up the reference), nitrates in
conjunction with proteins were found to form nitrosamines, which were
suspected of being carcinogenic.  Caffeine was found to intensify the
reaction.  This caused quite a stir not only among bacon lovers but also
among natural food advocates who combined fruits (source of nitrates) with
dairy products or grains (source of protein).  Further studies revealed that
a small amount of Vitamin C prevented the nitrosamines from forming.

My point was this:  our bodies are complex systems and the foods we eat
are complex aggregations of chemicals.  Pesticides are one, or at most,
a few chemicals, and they are chemicals we either know or suspect of being
toxic as well as carcinogenic.  We have evolved with the foods we eat;
our ancestors must have been able to survive on them or we wouldn't be
here.  Extreme reactions to staple foodstuffs would be counter-adaptive.
Agricultural pesticides have not been around in their present concentrations
during the evolution of the human species.

There's also a lot of evidence suggesting that we wouldn't need pesticides
if we didn't practice monoculture.  Humans have pruned the gene pools of
many of our staple crops through inbreeding and cloning.  There were once
thousands of strains of corn in North America.  Now most corn is
genetically identical.  All Bartlett pears and Bing cherries are clones
of one another.  This tendency towards identical genes in crop plants
makes the crops more susceptible to widespread insect plagues and
diseases.  We plant thousands of identical individuals of the same
age in the same place and wonder why we require so much chemical pest
control.

The classical mode of agriculture was to plant diverse crops (both
diverse species and diverse genomes within a species) in a family
garden or small farm.  Sure, you had insects and rodents and plant
diseases.  But you also had spiders and cats and preying mantii.
If you lost your cherries one year, it didn't affect your beans,
and the Smiths at the next farm might well have cherries.

Heather Mackinnon
Just a Self-taught Amateur
Any mistakes I make are the fault of my teacher.

chemical combinations we have evolved with than we are with single