One of the more frequently aired commercial breaks on Indian TV, is the one on a new luxury. The punch-line in the ad is ‘Where have all the men gone?’ The question led me to some contemplation, an offshoot from my mental exercises has been this write-up on evolutionary biology – a topic as remote from the thrust of the TV spot as is chalk from cheese – thence from , coming to chalk, which is of chemical salt, much like basalt, it sets me musing over a recent new research conducted by scientists from the Princeton University, which has identified the titanic Deccan Plateau upheavals and consequent lava outflow as one of the prime, if not the only, cause for mass extinction of dinosaurs.

The size and period of the basaltic eruptions over south central India, overlaps or gels with the era of mass extinctions of these giants. While the ‘meteorite crash’ theory lobbyists (both meteor impacts, the Chicxulub of Yucatan and Shiva meteor of India have been implicated as possible extra-terrestrial gatecrashers) look for ‘from the sky above’ answers for mass extinction, the Deccan Plateau upheaval and eruption backers, has espoused the ‘under the earth’ theory.

From remote cosmos or from an earth core, the fact remains, drastic and prolonged climate and atmospheric fluctuations engendered by any or all the above factors, is presumed to have wiped out a majority of life on earth, both floral and faunal – the most and singular and spectacular of the disappearances, being that of the dinosaurs. Although the event(s) ascribed to extinctions were both catastrophic and cataclysmic, was the wipe out of the terrestrial giant populations worldwide, as quick, sudden and immediate as assumed?

In the immediate aftermath of these events, factors that helped wipe out entire species, were intense heat, noxious gases, polluting chemicals, acid rain and increased levels of carbon dioxide.

In the light of data emerging from the field and laboratories on a new, but proven observations on Temperature Variation Dependant Sex Determination – time and again, in reptilia (crocodiles, turtles, agamids) it has been demonstrated that alterations in ambient hatching temperatures on eggs, influences the sex and hormonal levels in early embryos. Is it not inferable that dinosaur clutches of the K-T era, exposed to drastic shifts and variations in ambient atmospheric temperature levels, produced only either all male or all female hatchlings? Could this naturally engendered lop-sided alteration in sex ratio lead to emergence of a unisexual population dinosaurs? In this scenario, within a few generations, one or other sex would have dwindled in numbers or totally wiped out, leading to a chaotic or maybe violent mate hunting, followed by a total eradication of one or the other sex in geographically isolated dinosaur populations the world over.

An animal that ruled like an emperor over land on three continents or more, suddenly finds itself disabled from procreating –millions of years of reign comes to an agonizing and bizarre end. Death of a species, extinction of a form – all because some cosmic or earth core disruption has altered the ambient temperature of the world by a few degrees.

I can imagine a whole host of male T.rexes desperately searching for a female. Thousands of miles away, in another faraway continent, gasping female Rexes (or should it read Regina’s?!) pine as they scour the landscape, muttering “Where have all the men gone?”

http://blogs.nature.com/news/thegreatbeyond/2007/10/global_warming_mass_extinction.html