Web Historical Disclaimer:

This is a historical page and is no longer maintained at this location. Read our Web history statement for more information and visit the link(s) below to access the current version of the site.
The current OnCampus site can be reached at http://www.utexas.edu/oncampus


On Campus
          Office of Public Affairs | Contact Us | UT Home | Search UT  
SEARCH OPA Advanced
     A Publication of THE UNIVERSITY OF TEXAS AT AUSTIN
""

January 29, 2002
Vol. 28, No. 14

Headlines:

Homepage

UT faces projected deficit; proposes $230 increase in student fees

Teresa Graham Brett named dean of students

Behavior of midwater fishes under Antarctic ice: Observations by a predator

Student group displays pro-life exhibit at West Mall area

Meningitis ruled cause of university student's death

New study examines effects of memory training

Endowed scholarship honors Myers

Researchers get $4.5 million to study child language therapy

New engineering chair made possible by $2.35 million gift

Global extinction rate reaches historical proportions

Special programs highlight celebration of Black History Month

Nichols named associate vice president for research

Texas Exes to honor teachers for their excellence as educators

Equal Employment Opportunity/Affirmative Action Program Policy Statement

University approves new policy for lighting UT Tower

Coral study challenges long-held theory on glacial cycles

UT research shows radiation zapping Mars may affect biological evolution

Growing number of U.S.-Mexican border residents using herbs to treat ailments

News Briefs

Faculty Council

UT researchers receive $5.5 million to study effects of curricular changes in schools

Dana Center receives $94,000 award for math education

KUT adds Marketplace and The World to its program lineup

Arete: Harlan Miller

Critics program Viewpoint 2002 begins on Jan. 31

UT student returns home to conduct Corpus Christi Symphony in Rockport

SEARCH OPA


Advanced

""

   
"" ""

UT researcher: Global extinction rate reaches historical proportions

Half of all living bird and mammal species will be gone within 200 or 300 years, according to a university botany professor.

Although the extinction of various species is a natural phenomenon, the rate of extinction occurring in today’s world is exceptional — as many as 100 to 1,000 times greater than normal, Dr. Donald A. Levin said in the January-February issue of American Scientist magazine. The co-author is Levin’s son, Phillip S. Levin, a National Marine Fisheries Service biologist who is an expert on the demography of fish, especially salmon.

Levin’s column noted that on average, a distinct species of plant or animal becomes extinct every 20 minutes. Donald Levin, who works in the section of integrative biology in the College of Natural Sciences, said research shows the rate of current loss is highly unusual — clearly qualifying the present period as one of the six great periods of mass extinction in the history of Earth.

"The numbers are grim," he said. "Some 2,000 species of Pacific Island birds (about 15 percent of the world total) have gone extinct since human colonization. Roughly 20 of the 297 known mussel and clam species and 40 of about 950 fishes have perished in North America in the last century. The globe has experienced similar waves of destruction just five times in the past."

Biological diversity ultimately recovered after each of the five past mass extinctions, probably requiring several million years in each instance. As for today’s mass extinction, Levin said some ecologists believe the low level of species diversity may become a permanent state, especially if vast tracts of wilderness area are destroyed.

Other experts, in contrast, say breaking up today’s vast ranges into smaller habitats could promote the evolution of new species. That’s because populations of the same type of organism that are separated from each other may diverge over time. As populations are reduced in size, genetic changes may accumulate more rapidly. Another reason diversity may rebound — as it normally does after a major extinction episode — is that disturbances caused by human beings do not eliminate habitats, but merely change them.

top of page    next article

On Campus Produced by the Office of Public Affairs, The University of Texas at Austin
P.O. Box Z   Austin, Texas   78713-8926
512-471-3151   utopa@www.utexas.edu

News | Experts | Facts | Eyes of Texas | On Campus | Discovery

""