Natural Selections

This has been a good year for the signature wildflower of the northern forest spring. The trillium is a long-lived perennial that may grow 15 years before it puts out a short-lived bloom. Curt Stager and Martha Foley discuss this fleeting ornament of the forest floor.

This nocturnal nuisance can spray its cruel brew about as far as it can see: Ten feet. Martha Foley and Dr. Curt Stager get down to the basics: "How do you get rid of the skunk under the porch?

Various species of swallowtail butterfly are a common sight in fields and woodlands early in the year. Martha Foley and Dr. Curt Stager talk about their varieties, and how apparently different forms can occur within the same species.

This pest of the northern spring targets other species than humans. Some varieties annoy deer and some live in the tree canopy to bedevil the birds. Martha Foley and Dr. Curt Stager enumerate the victims.

Trees may live for hundreds, thousands of years, but there are limits on their growth. Trees can only move so much water, and only to a certain height. Martha Foley and Dr. Curt Stager discuss the hydrology of trees.

A common invasive species, the hover fly, or drone fly, looks remarkably like a honeybee. But in its youth, it carries the loathsome monicker "rat-tailed maggot." Martha Foley and Dr. Curt Stager discuss Batesian mimicry: innocuous creatures who imitate more dangerous species.

The complex web of species interaction is full of odd associations. Stocking a lake with fish cuts down on dragonflies, which helps pollinators, which helps the flowers bloom. Or it can cut down on amphibians such as newts, which is bad for garter snakes. Invasive flowering purple loosestrife is good for insects and birds that feed on them, but hard on plankton, which is at the bottom of the food chain for everything.Martha Foley and Curt Stager look an unintended consequences of human actions in nature.

Martha Foley? - not a fan of bugs. And Curt Stager took a course on them to steady his own reactions. The Natural Selections team looks at the outliers on the spectrum, the largest and smallest of critters with too many legs.New Zealand's weta makes a real handful. The fairy fly is nearly invisible. Some prehistoric dragonflies were big enough to make off with the cat.

Unlike organic material, which can be dated using carbon-14, stone and fossils often contain no carbon, or may be older than the carbon method can track. Radioactive potassium dating measures the ratio between a radioactive variety of potassium and the substance it breaks down into, argon gas. That can age material back billions of years. One problem: you need the gas to have been trapped in bubbles of volcanic ash.Martha Foley and Curt Stager discuss the problems of reading the geological clock.

Natural Selections Martha Foley and Curt Stager talk about the science of sugar maples: where the sap is stored in the winter, why it runs in the spring, and how the structure of the trunk differs from other trees.