 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| . |  |
. |
Hotter Is Better For Insects
Seattle WA (SPX) Oct 03, 2006 Organisms have been able to adapt to environments ranging from cold polar oceans to hot thermal vents. However, University of Washington researchers have discovered a limit to the powerful forces of natural selection, at least when it comes to the adaptation of insects to cold temperatures. "For thermodynamic reasons, cold temperatures present a challenging problem for ectothermic [cold-blooded] organisms because they slow biological processes, thus reducing rates of movement, feeding, and population growth," explains author M. R. Frazier. Many researchers believe that biochemical adaptations can eventually compensate for the effects of low body temperatures, but Frazier and his colleague's recent thermodynamic model, forthcoming in the October issue of The American Naturalist, argues against such compensation. To address this controversy, the researchers conducted a comparative analysis of published data on the thermal dependence of population growth rate for 65 insect species. They found that insects adapted to cold environments have slower maximum population growth rates than those adapted to warm environments, despite their long evolutionary history in such environments. "At least with respect to insect population growth rates," says Frazier, "our data suggest that hotter is better. We see little evidence of evolutionary compensation." This research suggests that adaptation to warmer or to colder temperature inevitably alters the population dynamics of insects, a result that has important consequences for agriculture, public health, and conservation. Related Links University of Washington Darwin Today At TerraDaily.com
A Plan For Reintroducing Megafauna To North America
Chicago, IL (SPX) Oct 03, 2006Dozens of megafauna (large animals over 100 pounds) - such as giant tortoises, horses, elephants, and cheetah - went extinct in North America 13,000 years ago during the end of the Pleistocene. As is the case today in Africa and Asia, these megafauna likely played keystone ecological roles via predation, herbivory, and other processes. What are the consequences of losing such important components of America's natural heritage? |
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement |
