James W. Kirchner is professor of Earth and Planetary Science at University of California, Berkeley

University of California, Berkeley

The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...

. His current research spans the fields of geomorphology

Geomorphology

Geomorphology is the scientific study of landforms and the processes that shape them...

, hydrology

Hydrology

Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...

, environmental geochemistry, evolutionary ecology

Evolutionary ecology

Evolutionary ecology lies at the intersection of ecology and evolutionary biology. It approaches the study of ecology in a way that explicitly considers the evolutionary histories of species and the interactions between them. Conversely, it can be seen as an approach to the study of evolution that...

, and paleobiology

Paleobiology

Paleobiology is a growing and comparatively new discipline which combines the methods and findings of the natural science biology with the methods and findings of the earth science paleontology...

. He currently serves as the director of Berkeley's Central Sierra Field Research Stations.

A study by Kirchner and Anne Weil showed that the time taken for life on earth to recover from extinction

Extinction

In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

 episodes such as that which destroyed the dinosaurs is not, as previously thought, proportional to the damage done. Instead, Kirchner and Wiel, analyzing fossil record data compiled by Jack Sepkoski

Jack Sepkoski

J. John Sepkoski Jr., , was a University of Chicago paleontologist. Sepkoski studied the fossil record and the diversity of life on Earth. Sepkoski and David Raup contributed to the knowledge of extinction events...

, found that recovery time for catastrophic die-offs was about 10 million years regardless of the number of species lost. Kirchner has also been very active in the evolution of the Gaia hypothesis

Gaia hypothesis

The Gaia hypothesis, also known as Gaia theory or Gaia principle, proposes that all organisms and their inorganic surroundings on Earth are closely integrated to form a single and self-regulating complex system, maintaining the conditions for life on the planet.The scientific investigation of the...

, though not necessarily supportive of it.

External links

• Homepage; accessed 19 January 2007