Printer Friendly

Tropical diversity came with time.

Species in the richly diverse tropics don't evolve any faster than do species in temperate zones, researchers report.

Rather, the tropics accumulated its astounding abundance of species largely because life has thrived there so long.

Why the low latitudes teem, flutter, buzz, and slither with so much more diversity than the temperate zones do is a long-standing question. Biologists have proposed a rich abundance of hypotheses, notes John Wiens of the State University of New York at Stony Brook. In the 1990s, several researchers devised versions of what Wiens calls the tropical-conservation hypothesis. It argues that many of the tropics' species-rich lineages originated there and were slow in colonizing the temperate zones that have killer winters. Thus, life in the tropics has had longer to diversify.

Wiens and his colleagues tested the idea in tree frogs. Working with a researcher at San Diego State University, the Stony Brook team constructed and analyzed a family tree of 124 species of tree frogs.

The analysis roots the tree in tropical South America. The researchers found that the longer a lineage lived in any region, the more likely it was to have diversified into lots of species. They also report that tropical lineages didn't branch any faster than the temperate ones. The team's findings appear in the November American Naturalist.
COPYRIGHT 2006 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2006, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:evolution in tropical zones is less than temperate zones
Author:Milius, Susan
Publication:Science News
Article Type:Brief article
Geographic Code:1USA
Date:Oct 21, 2006
Previous Article:Prepared brains achieve insight.
Next Article:Cloning is most efficient using non-stem cells.

Related Articles
Parasite power: in the perpetual race between parasite and host, evolution appears the winner.
Rare fossils of enigmatic amphibian.
Tropical diversity: evolutionary cradle.
The temperate rainforest: Canada's clear-out secret.
Blackened mangrove, smothered reef; years later, oil still sickens tropical coastal ecosystems.
The tropical majority: have studies of temperate-zone birds warped our view?
Older ancestors: primate origins age in new analysis. (This Week).
Tropical peat swamp forests of Southeast Asia: ecology and environmental importance. (Abstracts).

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters