Desert Mice and Natural Selection
Rock pocket mice are common denizens of the Sonoran desert regions around Tucson, but you'll probably never see one in the wild. The small rodents are strictly nocturnal, finding refuge from the daytime desert heat in their underground burrows. By night, they gather seeds, their only source of food and water, and do their best to elude owls, their main predators.

Now, these inconspicuous animals may have gained some celebrity as a textbook example of adaptation by natural selection, thanks to a team of University of Arizona evolutionary biologists.

The group, led by Professor of ecology and evolutionary biology Michael W. Nachman, examined the coat colors of rock pocket mice. Most of the mice have light tawny fur, which blends in well with the desert granite substrates they typically inhabit.

But scattered throughout the southwest are islands of black basaltic rock formed from not-so-ancient lava flows. Nachman's group collected pocket mice from two of these black rock islands Ð the Pinacate formation in Southwestern Arizona and the Pedro Armendaris formation of New Mexico. Almost all of the mice collected from the volcanic formations had dark coats Ð the better to stay concealed from hungry owls, which can pick off mice from contrasting backgrounds even at night.

H. Jay Melosh Elected to NAS
University of Arizona Professor H. Jay Melosh of the Lunar and Planetary Laboratory (LPL) has been elected to the National Academy of Sciences, one of the most prestigious honors in American science. He joins 21 other UA scientists who are members.

The Academy, chartered in 1863 by President Abraham Lincoln to guide public action in science, recently elected 72 new members and 18 foreign associates from 11 countries in recognition of their distinguished and continuing achievements in original research.

"Jay Melosh literally wrote the book on impact cratering," said Michael Drake, head of the LPL and UA planetary sciences department. "His 1989 book made us all aware of the importance of extraterrestrial impacts in shaping our Earth. The book ("Impact Cratering: A Geologic Process," Oxford University Press) is still the universal reference used by all scholars."

His work led to an understanding of the origin of the moon and the creation of the Chicxulub Crater from a huge impact 65 million years ago. Melosh and others say the crater killed dinosaurs and most of the living species on Earth.

UA Researchers Head SIRTF Teams
Our Milky Way galaxy will produce about one new star this year. But this year other nearby galaxies will pump out hundreds of new stars. Still other nearby galaxies gave birth to their last star about 10 billion years ago. Astronomers will use all three Space Infrared Telescope Facility (SIRTF) science instruments in nearly all modes to discover why some of our galactic neighbors are prolific or now barren in a SIRTF Legacy Science Program called "SINGS." SIRTF is the fourth and last of NASA's Great Observatories.

"Our program begins in earnest about four months after launch," said University of Arizona astronomy Professor Robert C. Kennicutt Jr. He leads a team of 22 scientists based at the UA Steward Observatory, the Space Telescope Science Institute in Baltimore, Md., California Institute of Technology's SIRTF Science Center and six other institutions in the "SIRTF Nearby Galaxy Survey," or SINGS. The launch is scheduled for no earlier than mid August.

Five other teams, including one headed by UA astronomer Michael R. Meyer, also were chosen for the SIRTF Legacy Science Program. Meyer is principal investigator for a team that will use the SIRTF in the Legacy Science Program project, "The Formation and Evolution of Planetary Systems: Placing Our Solar System in Context."

"We will look for signatures of planets that sculpt circumstellar dust in a sample of more than 300 solar-like stars ranging in age from 3 million to 3 billion years," said Meyer.

UA Scientist to Study Red Mars Dust
On Mars, dust rules. Red dust is omnipresent on the Red Planet. There are dunes everywhere. Dust floats in the thin Martian air and whirls about the planet in dust storms and dust devils. It falls out of the air and onto Mars' rocky features.

On Mars, says Peter H. Smith, dust is the defining feature of the atmosphere, much like water and the hydrological cycle is the major force in Earth's atmosphere. Like water on Earth, dust is the major force eroding the surface of Mars. Smith, a scientist at the University of Arizona Lunar and Planetary Laboratory whose IMP camera was perhaps the most publicly notable success in the Mars Pathfinder mission several years ago, is one of more than two dozen scientists who will participate on the next NASA mission to Mars.

The Mars Exploration Rover (or MER), which is actually two vehicles that are designed to study the Martian environment, is scheduled for launch in June 2003. The two rovers are targeted to land on two separate parts of Mars in early 2004. "Not much is known about the dust on Mars," Smith said. "We'll be looking at how dust piles up on surfaces, how it accumulates and how it gets off of surfaces."

Smith says this wasn't the initial goal of the MER mission, but NASA has recognized its importance, judged, he said, by the number of atmospheric scientists included in the mission. That includes Mark Lemmon, an atmospheric scientist from Texas A&M University, one of Smith's longtime collaborators.

AAAS Elects Astronomer George Rieke
The American Academy of Arts and Sciences has elected University of Arizona astronomy Professor George H. Rieke to its 2003 class of Fellows.

The American Academy, the nation's oldest learned society, is composed of the world's leading scientists, scholars, artists, business people and public leaders. Founded in 1780 by John Adams, James Bowdoin, John Hancock, and other scholar-patriots, the academy acknowledges the best of all scholarly fields and professions, said Academy President Patricia Sparks. The 187 newly elected Fellows and 29 Foreign Honorary members of 2003 were selected through a highly competitive process.

Rieke, who is deputy director of the UA Steward Observatory, was elected in the Academy's mathematics and physics category. He was cited for his contributions as an infrared observer and instrumentalist.

"George has been a real pioneer of infrared astronomy. He has been with it since it started," said Steward Observatory Director Peter A. Strittmatter. "His subsequent work over the past 25 to 30 years has led to great advances in infrared instrumentation and science. He is one of the most highly cited astronomers, let alone infrared astronomers. He is passionate about infrared astronomy. He is a pillar of Steward Observatory."

Red squirrel on mt. Graham topic of UA symposium
Over the past dozen years, government and university scientists have amassed a wealth of new information on the endangered Mount Graham red squirrel. Much of the research has been funded by the UA Steward Observatory, which is developing the Mount Graham International Observatory (MGIO) in the Pinaleño Mountains that rise above Safford, in southeastern Arizona. Steward Observatory, as mandated, has funded ecological studies on Mount Graham at $50,000 a year for the past 10 years, and will continue to fund the Mount Graham Red Squirrel Monitoring Program for the life of the MGIO.

No doubt about it, the genetically unique red squirrels on Mount Graham are vulnerable to extinction, biologists reported in May 2003 at the UA-sponsored "Symposium on the Endangered Mount Graham Red Squirrel: Ecology, Conservation, and Management."

Symposium co-sponsors were Arizona Game and Fish Dept., U.S. Fish and Wildlife Service, Coronado National Forest, the Arizona Chapter of the Wildlife Society, and the Southwest Section of the Wildlife Society. Proceedings will be published this year, said H. Reed Sanderson of the UA Vice-President for Research Office, chairman of the Mount Graham Red Squirrel Committee and symposium organizer. (Report on Research dispatched UA science writer Lori Stiles and national news coordinator Julieta Gonzalez to the symposium to gather information about the University's research taking place on Mount Graham for a future issue.)

Somehow the Mount Graham red squirrels are hanging on to their home of the past 11,000 years, now a "sky island," a spruce-fir-topped mountain rising out of the desert. Their numbers, 300 or fewer by latest available count, fluctuate according to the abundance of their major food source, the conifer cone crop.

But other, not-so-apparent factors are now taking their toll on the red squirrels, scientists said at the symposium. Native beetles and exotic aphids have recently invaded the drought-stressed conifers on Mount Graham, and the insect outbreaks have killed hundreds of acres of trees in prime squirrel habitat.

Last year Forest Service fire fighters contained 22 blazes before they burned out of control, as did the 1996 Clark Peak Fire that consumed 6,300 acres of trees and came within 200 yards of the observatory. Forest managers worry about endangered squirrel survival in a dry forest where the fuel load can include as much as 200 tons of dead wood per acre.