> Problem is that reality may not be quite as black and white as the theory
> above. What happens when those consumed toxic items are only seasonably
> available or available in small quantities? Does a threshold amount, both
> volume-wise and periodic-wise, exist above which selection occurs?
Old toxicology principle: The dose determines the poison.
Mark points out one shining example: alcohol. Beneficial in small amounts;
detrimental in large amounts (and, to a lesser degree, in no amount).
Virtually every substance has a threshold dose, above which ingestion is
detrimental. With some "toxic" substances, the threshold dose is very low
(ex. benzene)
Rob