Consider the Delhi Sands flower-loving fly.
Down to a relative handful of individuals, this insect - all one inch of it - is found only in two counties in California.
If this teensy critter slipped into oblivion, became a minuscule version of the Dodo bird, would it make any difference? Or if it were somehow pulled back from the brink of extinction, would anybody care?
There's more to the fly story, including a likely appearance before the Supreme Court of the United States. But hold that thought for a moment now and consider the bald eagle, America's national icon.
If the eagle - proud symbol of courage and strength - were to somehow disappear (as it very nearly did), there would be general mourning. And if it revived to the point where it could be removed from the official list of endangered species, huzzahs would be heard across the land.
As it turns out, not only the bald eagle but such other well-known species as the peregrine falcon and the gray wolf have recovered to the point where experts say they now require less official protection in the wild.
Federal officials this week proposed to "delist" or to "downlist" (to a lesser level of protection) some two dozen species now protected under the Endangered Species Act.
"They made it. They're graduating," said Interior Secretary Bruce Babbitt. "They're coming back to their native American soil, water, and wind."
Politics of conservation
The story is as political as it is biological.
Critics of the highly controversial Endangered Species Act (ESA) say it's failed over the course of its 25 years. Only a dozen or so species have ever been removed from a list that has grown to 1,135 plants and animals - and most of those because they shouldn't have been there in the first place or because they went extinct before recovery plans could save them.
But due to the efforts of private landowners and government agencies, many declines have been reversed. The peregrine falcon, for example, has grown from just 30 to 35 active nest sites to some 1,500 breeding pairs (including "Eleanor" and "Franklin," now guarding their offspring on the 14th-floor ledge of a Chicago Housing Authority building).
The number of Canadian wolves reintroduced into Idaho and Yellowstone National Park beginning in 1995 has grown from 66 to 160. And the bald eagle can regularly be seen with Seattle's skyline in the background.
Such stories may help supporters of the ESA in their effort to have the law reauthorized.
But it's not just the larger, more attractive "charismatic mega-fauna," as they're called, that scientists say are important.
Many esoteric species are crucial to the manufacture of pharmaceuticals and many other products, for example, and others may be even more important for the role they play in maintaining nature's biodiversity. And yet about 85 plants and animals are added to the endangered species list every year.
The World Conservation Union last month reported that more than 12 percent of the world's ferns and seed-producing plant species (nearly 34,000 in all) face extinction due to habitat loss and the invasion of exotic species tied to human activity. In the United States, according to this 20-year research effort the figure is even higher: some 29 percent of such species (about 16,000) are at risk.
Harvard University biologist E.O. Wilson, a leading authority on biodiversity, warns that the loss of certain "keystone species" - nobody knows which ones they are - could cause a collapse of ecosystems.
A recent survey of biologists by the American Museum of Natural History found 70 percent concerned that a mass extinction could result in a "major threat" to human life.
At the same time, there is considerable opposition to protecting what some see as lesser species - particularly if restrictions such as those against harming ESA-listed plants and animals bring an economic impact.
The National Association of Home Builders, for example, is suing to stop the listing of the Delhi Sands flower-loving fly. In March, the builders' trade group took its case to the United States Supreme Court.
The group charges that "the federal government has gone to extraordinary lengths to ensure the fly's health and well-being, including forcing San Bernardino County to move the site for a hospital 250 feet and fence in eight acres of fly preserve - directives that added more than $3.5 million to the cost of the hospital."
Such stories may seem ludicrous to the general public. But supporters of the Endangered Species Act say it makes no difference whether an endangered species looks like a weed or a grizzly bear.
"The elusive Virginia northern flying squirrel or the lowly Missouri bladder-pod are less charismatic but just as ecologically essential," says Secretary Babbitt, referring to two species recovered to the point where they could be downlisted from "endangered" to "threatened."
"And all are equal members of God's creation," Babbitt adds.
Federal officials this week proposed to "delist" or "downlist" some two dozen species now protected under the Endangered Species Act. Some of them include:
American peregrine falcon
Aleutian Canada goose
Columbian white-tailed deer
Virginia roundleaf birch
Running buffalo clover
Lloyd's hedgehog cactus
Loch Lomond coyote-thistle