Sir, – The sexes (aka, the genders) are indeed “different and behave differently” as outlined by Prof William Reville (Science, April 4th), and this has been the case from the very beginning.
The first sexual organism reputedly is the red alga, Bangiomorpha pubescens , a fossil dating from 1,200 million years ago. While the naming author clearly had his tongue firmly in his cheek when he chose the epithet, sexual characteristics as we know them today were clearly evident.
Initially, sexuality in primitive bacteria and algae was simply a matter of identical organisms exchanging genetic material, but selection for a “female” sex was very strong as the offspring had a better chance of survival if the “female” was larger, sessile and packed with nutriment. The “male” was smaller, motile and was attracted to the female by chemical means, via pheromones.
Little has changed in the intervening 1,200 million years and such sexual differences are axiomatic. – Yours ,etc.
MICHAEL D GUIRY,
Professor Emeritus of
Botany,
Ryan Institute,
NUI Galway,
Galway.