[meteorite-list] Bees Survived Dino Extinction

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Nov 23 18:23:13 2004
Message-ID: <200411232323.PAA27069_at_zagami.jpl.nasa.gov>

http://news.bbc.co.uk/2/hi/science/nature/4030933.stm

Bees survived dino extinction
BBC News
November 23, 2004

New evidence shows tropical honeybees survived the post-impact winter 65
million years ago that is thought to have helped kill off the dinosaurs.

An asteroid is thought to have hit our planet at the end of the
Cretaceous Period, throwing up dust that blocked sunlight and dragged
down temperatures.

Honeybees trapped in amber before the asteroid strike are nearly
identical to their modern relatives, data shows.

Details were given at the Geological Society of America's 2004 meeting.

The asteroid or comet that created the Chicxulub impact structure in
Mexico occurs at the boundary between two geological periods: the
Cretaceous and the Tertiary.

This geological boundary marks a mass extinction that wiped out
dinosaurs and many other groups of organisms.

The finding throws up all sorts of questions, researchers say, because
current models of the post-impact winter suggest global temperatures
fell far enough to have killed off honeybees and many of the flowering
plants they lived off.

Modern tropical honeybees have an optimal temperature range of 31-34C
(88-93F) in order to maintain vital metabolic activities.

This is also the range that is best for their food source: nectar-rich
flowering plants.

Temperature sensitive

Based on what is known about the Cretaceous climate and modern tropical
honeybees, Jacqueline Kozisek of the University of New Orleans, US,
estimated that any post-impact winter event could not have dropped
temperatures more than 2-7C (4-13F) without wiping out the bees.

Current theories about the Chicxulub impact winter estimate drops of
7-12C (13-22F) - too cold for tropical honeybees.

If no modern tropical honeybee could have survived years in the dark and
cold without flowering plants, says Kozisek, something must be amiss
with the impact winter theory.

"I'm not trying to say an asteroid impact didn't happen," said Kozisek.
"I'm just trying to narrow down the effects."

Kozisek dug through the scientific literature to find out what survived
the massive extinction event.

"I made a list of all survivors and picked those with strict survival
requirements," said Kozisek.

She determined what those survival requirements were by calling on
studies of the most similar organisms living today.

She found that tropical honeybees had changed little in 65 million years.

Amber-preserved specimens of the oldest tropical honeybee Cretotrigona
prisca are almost indistinguishable from some of their modern
counterparts. This means they could even be their ancestors, researchers
think.
Received on Tue 23 Nov 2004 06:23:08 PM PST