Natural Selections

Ravens were once a rarity in the North Country, but now they are becoming a common sight. They have a similar appearance to crows, but if you see the two birds together the difference is fairly obvious. Curt Stager and Martha Foley discuss ravens and crows on Natural Selections.

Of all the places a cat can hang out, why do do many of them want to hang out in boxes? According to researchers, cats that spend time in close confines are measurably less stressed than those remaining in the open. As Curt Stager tells Martha Foley, it's not just house cats who feel this way.

The pressure to keep billions of humans fed can have a transformative impact on amimal populations. Overharvesting that targets the largest animals can result in reduction of the average size of species, as seen in Caribbean conch snails. And sport-fishing pressure on large mouth bass can winnow out the most agressive in the gene pool, resulting in a "lazier," more passive remnant population. Martha Foley and Curt Stager talk about the human factor in animal evolution.

Keratin, the substance wool, hair, and feathers are made from, makes a pretty thin diet, but the clothes moth has been dogging humanity's closets and drawers for hundreds of years, unravelling the work of generations of knitters and weavers to feed its larvae.

Humans, birds, and whales are not the only creatures who can sing. Martha Foley and Dr. Curt Stager discuss recent research that uncovered bats also use learned songs to communicate.

Martha Foley has never succeeded in keeping a nature journal long-term, but Curt Stager finds them invaluable in his work. He records his observations on paper, but also finds great data through researching the journals of past observers, from Samuel de Champlain to Thomas Jefferson, to ordinary little-known North Country folk. His hint - always put it on paper. Whatever became of all that stuff on your floppy diskettes?

We tend to think that dogs do this, and that cats do that. We think animal species have a recognizable set of behaviors that define the nature of their kind. But what about individual animals? Does each have something we could understand as a unique personality?

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.

All creatures breathe in some fashion, but how the job gets done has changed from fish to amphibian to reptile to mammal. Curt Stager and Martha Foley chart the evolution of animal respiration.

The ubiquitous bird of cities and towns was designed for a different environment. The pigeon's distinctive style of flight is adapted for maneuverability in tight places - near vertical takeoffs and quick changes of direction. This adaptation to cliff and mountainside environments serves them well among our urban cliff dwellings. Curt Stager and Martha Foley discuss.

Pigeons and doves, both domestic and feral, are the same species. Today's urban environment mimics their original favored habitat, seaside cliffs in Europe and Asia. Martha Foley and Curt Stager discuss this commonest bird companion in densely settled areas.

The Northern Flicker is one of the most recognizable birds. This distinctly-marked member of the woodpecker family, instead of browsing wood for their food like their relatives, digs for food in the ground. Martha Foley and Curt Stager explore its habits.

Animals that resemble each other may not be closely related. Sometimes the setting shapes their bodies more than their ancestry. Manatees may look like whales or walruses, but that is only because they adapted to the marine environment in a similar way. Martha Foley and Curt stager talk about convergent evolution.

The big marine herbivore, the manatee, is thought by some to be the origin of mermaid legends, but it's not closely related to humankind or even to whales and other marine mammals.

Lake trout require a lot of cold, oxygenated water to survive. Lakes in the Adirondacks of upstate New York are at the southern edge of their natural range. Although about 100 Adirondack lakes and ponds are still home to lake trout, even a small increase in temperature could sharply cut that number.

Researchers have found that variations in the wingspan of cliff swallows has a measurable impact on their survival in a human-dominated environment.

A coral reef is kind of like Manhattan, a huge number of mouths to feed in a packed parcel of real estate. A reef doesn't have upstate farms to keep them all fed. So how do they get by?

Curt Stager has his students start the semester by picking out a "pet rock." At the end of term, they have to tell the story of that rock - what it is, what it's made of, and what happened to shape it it over the ages.

You can get the sugar out of a lot of trees, but there's something special about the sugar maple. Its trunk is highly efficient at storing and moving sap. That's in part because the sap is stored throughout the trunk, rather then down in the roots, as with most trees in winter. Martha Foley and Curt Stager look at that other "sweet science," the one behind our favorite breakfast condiment.

Martha Foley and Dr. Curt Stager discuss cosmic rays. While many people may think cosmic rays only affect astronauts or satellites - objects in space - computers and other electronic equipment on Earth can be affected, too.

Few creatures move with more grace than deer. Martha Foley compares them to ballerinas. Curt Stager says there's a reason for that. As ballerinas often do, deer walk on their tip-toes.

In general, plants make food from sunlight, and animals fuel themselves by "burning" oxygen. But some animals think outside the box. Curt Stager and Martha Foley look at a photosynthetic slug that hijacks the genetic machinery of the algae in its diet, and at a jellyfish that needs no oxygen, burning the alternative fuels of hydrogen and sulfur.

"In the case of the voles and the shrews, they'll actually shrink their total body mass down, so there's less body to have to be fed."

It's the reason opposites attract and doorknobs shock, why lightning strikes, and the way bumblebees find the sweet spot in flowers. Whenever an object has more or fewer electrons than its neighbor, there is the potential for static discharge. Martha Foley and Dr. Curt Stager talk about the mysterious and hair-raising ways of static electricity.

What is a flame? Why is it shaped like that? How does it keep going? Martha Foley and Dr. Curt Stager answer some burning questions about rapid oxidation.

Dr. Curt Stager tries once again to answer the classic child's question. It is a poser that was worthy of Einstein's time, who eventually came up with the best answer. But it's complicated. And when the sky isn't blue, why not? What's up with that? Martha Foley wants to know.

Since our bodies replace most cells over a period of a few years, it raises the question "Is any part of us original equipment?" According to Curt Stager and Martha Foley, the answer is "Yes." Parts of the eyes and teeth, as well as many nerve and (bad news for dieters) fat cells last a lifetime.

Rarely seen during the day, flying squirrels don't actually fly, but use flaps of skin that connect their fore and hind legs that enable them to glide up to a hundred feet, between trees and from tree to ground.

Snowy owls are normally a rare sight in North Country. Their usual range is in the Arctic north. But a few years ago, a large number were seen all across the region. Martha Foley asked Dr. Curt Stager why that has happened.

Unlike frogs, turtles don't hibernate through the winter. In fact, sometimes you can see snappers and other species moving around under the ice. While their metabolism runs at very low ebb in the cold, they remain alert to changes in light and temperature that signal the coming spring. How do they survive without oxygen? As Paul Smith's College biologist Curt Stager tells Martha Foley, they get energy from their body tissues, and their shells neutralize the resulting lactic acid build-up.

Martha Foley and Curt Stager talk about ochre. It’s more than just a color in the Crayola box.

The success of the Clean Air Act in reducing acid deposition in Adirondack lakes is an under-reported good news story. Many lakes once devoid of life can now support healthy fish populations and other aquatic life. But as Curt Stager discusses with Martha Foley, the life that returns to recolonize the water is not the same as what was lost. Sediment cores show that the original algae and plankton varieties that form the base of the food chain and were unchanged for hundreds of years are being replaced by different varieties. A balance has been restored, but it's a new balance, tipped perhaps by warming, and by invasive species.

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.

What happens when certain species of domesticated animals like chickens and pigs escape to live and breed in the wild? According to Curt Stager and Martha Foley, after a few generations they start to look and act like their wild ancestors again.

Our atmosphere is about 80 percent nitrogen. Martha Foley and Dr. Curt Stager explore the ways this common element and necessary component of all life forms interacts with the biosphere.