Natural Selections

The last time the climate warmed the Sahara was green and had a huge lake in the middle that left behind vast deposits of fine mineral-rich sediments. In these drier days the dust from that ancient lakebed now blows all the way across the Atlantic to nourish the Amazon with phosphorus and the ocean with iron.

It also shades the patch of the Atlantic where hurricanes form, lessening the strength and frequency of tropical storms that reach the North Country. The current trend back toward a warmer world might be good for the Sahara, but not so good for us. Curt Stager and Martha Foley explain.

The last time the climate warmed the Sahara was green and had a huge lake in the middle that left behind vast deposits of fine mineral-rich sediments. In these drier days the dust from that ancient lakebed now blows all the way across the Atlantic to nourish the Amazon with phosphorus and the ocean with iron.

It also shades the patch of the Atlantic where hurricanes form, lessening the strength and frequency of tropical storms that reach the North Country. The current trend back toward a warmer world might be good for the Sahara, but not so good for us. Curt Stager and Martha Foley explain.

Cuttlefish, a relative of the squid, is a favored food of sharks. It has a number of ways to avoid that fate, however, such as swimming away or taking on protective coloration.

A new study has discovered that cuttlefish are remarkably adept at playing dead and can even still the electrical impulses from muscles that a shark would detect.

The luna moth uses a different technique to escape becoming bat chow. The long "tails" that trail back from behind their wings confuse the echolocation of bats.

The bat might wind up with a little piece, but miss the body of the moth.

Curt Stager and Martha Foley discuss unique survival skills in prey animals.

Fallout from atmospheric testing of nuclear weapons has distorted the background levels of the radioactive isotope carbon-14, used by archaeologists to date organic materials

But it has an upside, providing a new scale by which to date more recent events, helping researchers track cell turnover in different parts of the body and in testing the age of everything from vintage wine to elephant ivory.

Curt Stager and Martha Foley discuss radiocarbon dating.

Listen to Natural Selections every Thursday morning on The Eight O'Clock Hour on NCPR

Black squirrels are becoming more common throughout the St. Lawrence Valley. They are a normal variation of the more familiar gray squirrel species. Martha Foley and Dr. Curt Stager discuss melanism, an increase in the pigmentation of some species that can be a response to environmental factors.

Most carnivorous plants, such as the pitcher plant commonly found in Adirondack bogs, live in poor soils. Unwary insects are drawn to a sweet bait to supplement their diet. Curt Stager and Martha Foley discuss these botanical oddballs, which may live as long as 50 years.

The Greeks called them "The Seven Sisters," but a look at the Subaru logo shows the Japanese saw them differently. This familiar star cluster constellation actually contains thousands of stars when viewed through a telescope, as well as brown dwarf proto-stars and dust nebulae and newly-forming solar systems. Martha Foley and Curt Stager look at the night sky.

Martha Foley and Dr. Curt Stager talk about stars and the very clever ways we can tell their distance from the earth.

Martha Foley and Dr. Curt Stager talk about stars and the very clever ways we can tell their distance from the earth.

All the pet hamsters in the world derive from a small wild population collected in Syria in the 1930s. Martha Foley and Curt Stager talk about hamsters, in the wild and working the wheel.