An eagle glides in for a landing, a porcupine diligently strips bark from a tree limb, elk plod through a lake shrouded in mist, a polar bear and her cub survey miles of frozen landscape.

These are part of a vivid new photo exhibit that opens today at the Monte L. Bean Life Science Museum at Brigham Young University. "Vital Signs: Images of Biodiversity," displays prints by nature photographer Thomas D. Mangelsen, whose images have been published by National Geographic, Audubon, Geo, National Wildlife and other magazines.The display continues through April 24, from 10 a.m. to 9 p.m. weekdays and from 10 a.m. to 5 p.m. Saturdays. The museum does not charge admission.

The pictures are divided into five categories: vital signs, which looks at the signs of life, from microscopic genes to forests covering hundreds of square miles; portraits, which focuses on individual animals; patterns, which looks at the way life revolves around collections of individuals like flocks of swans; contact, showing the interaction of different species; and horizons, showing the land and its many levels of life.

"Tom Mangelsen has gone all over the world taking pictures of animals in their natural habitats," said Douglas C. Cox, the museum's assistant director. "He has come to believe strongly that there are some animals and some habitats that are in danger."

The exhibit tries to show that "these marvelous, wonderful, beautiful creatures are in peril."

Museum staff members are thrilled with the 40 or 45 photos. "They come as we're hanging (the exhibit) and say, `Wow! Look at that one,' " Cox said.

The Mangelsen photos are displayed in connection with the museum's annual nature photography contest and exhibit, which will be shown through March 25.

In addition, the Tanner Lecture, a free public talk to be held in the museum on March 26, will focus on biodiversity. The speaker will be Don Wilson, director of the biodiversity programs at the Smithsonian Institution in Washington, D.C.

Mangelsen was raised in Nebraska. He studied wildlife biology but turned to filmmaking and then still photography. He has been a nature photographer for more than 20 years. In 1994 the British Broadcasting Corp. named him the wildlife photographer of the year. His work can be seen in 10 galleries, two of them in Utah.

A printed portfolio of the pictures in the exhibition opens with a quote from Mangelsen: "If there's a magic ingredient in my art, it's not a special camera or secret film - it's biodiversity - the deep texture of an old growth forest, the bright sheen of an exotic feature or the simple beauty of a monarch butterfly repeated again and again until it fills a meadow."

The exhibit was produced with help from the San Diego Natural History of Museum and Images of Nature galleries, a string of galleries that carry Mangelsen's photos. The galleries reach from Hong Kong to California, Illinois, Wyoming, Colorado, Nebraska and Utah. This state has two of them, in Park City and Deer Valley.