PARIS, Oct 10, 2007 (AFP) - Scientists have uncovered what might be called the law of language evolution: the more a word is used, the less likely it is to change over time.

Like genes, words undergo ruthless survival-of-the-fittest pressure and those which are less central to daily life are subject to mutation, according to their study.

Their research applies mathematical precision to four very different Indo-European languages -- but if it holds for other languages as well, it would be a milestone in understanding one of humanity's defining attributes.

TOKYO, Sept 27, 2007 (AFP) - Japanese researchers have succeeded in producing see-through frogs, letting them observe organs, blood vessels and eggs under the skin without performing dissections.

'You can see through the skin how organs grow, how cancer starts and develops,' said the lead researcher Masayuki Sumida, professor at the Institute for Amphibian Biology of state-run Hiroshima University.

PARIS, Sept 24, 2007 (AFP) - From post-coital cannibalism to love at first sight, the sex life of the African jumping spider is full of surprises, according to a new study.

But none is more unexpected than this, say researchers who studied the blood-gorging Evarcha culicivora up close and personal: while virgin females are attracted to meatier mates, a bit of experience sees them switch to smaller partners.

SCHULMAN GROVE, California, Sept 22, 2007 (AFP) - They have neither the soaring majesty nor the celebrity of the giant redwood, but in one respect the bristlecone pine is the undisputed king of trees: longevity.

Scattered on a remote mountainside of eastern California, these gnarled, twisted specimens are the oldest living organisms on Earth, the most senior among them some 4,700 years old.

PARIS, Sept 17, 2007 (AFP) - Cyprian honey bees under attack by predator hornets have evolved a grisly and lethal way of fighting back which scientists have called 'asphyxia-balling,' according to a study published Monday.

An intruding hornet looking for a snack in a beehive may suddenly find itself enveloped inside a buzzing ball of black-and-yellow worker drones. The bees squeeze in tightly around the abdomen -- where hornets breath -- until the would be aggressor dies of suffocation.

PARIS, Aug 13, 2007 (AFP) - Forget jutting jaws, pheromones or hypnotic stares. What has made men sexy since they lived in caves could well be a foreshortened face, according to a new study.

Theories abound as to why humans are attracted to each other, and on the role facial features might have played in the human evolutionary saga.