Cold is hot in evolution -- Researchers debunk belief species evolve faster in tropics

Mar 15, 2007

University of British Columbia researchers have discovered that contrary to common belief, species do not evolve faster in warmer climates.

UBC Zoology PhD candidate Jason Weir and his mentor Prof. Dolph Schluter, director of the UBC Biodiversity Research Centre, charted the genetic family tree of 618 mammal and bird species in the Americas over the last several million years.

By analyzing the DNAs of species that are closely related to one another, the researchers found that speciation – the process in which one species splits into two – takes place faster in temperate zones than in the tropics. Their findings are published in today’s edition of the journal Science.

"It’s been long established that the tropics have more species, but it’s not clear why," says Weir. "The common assumption is that species simply evolve faster in warmer climates."

"Our analysis shows that new species actually evolve faster as we move towards the poles. It would take one species in the tropics three to four million years to evolve into two distinct species, whereas at 60 degrees latitude, it could take as little as one million years."

The higher speciation rate in higher latitudes, however, is counteracted by a high extinction rate, both likely due to more intense climate fluctuations, says Weir.

"In comparison, even though there is a lower speciation rate in the tropics, the stable environment contributes to an equally low extinction rate. As a result, more species survive. This could help explain why there are more species in general in warmer climates," says Weir.

"In other words, there’s a higher turnover of species in places like Canada, making it a hotbed of speciation, not the Amazon," says Schluter.

Source: University of British Columbia

Explore further: Powerful tool promises to change the way scientists view proteins

add to favorites email to friend print save as pdf

Related Stories

Screening plants for potential natural products

Jan 21, 2015

Humans have been making use of plants for as long as there have been humans and plants. The actual cultivation of plants for food and other products began with the Neolithic Revolution some 12,000 years ago ...

International team maps 'big bang' of bird evolution

Dec 11, 2014

The genomes of modern birds tell a story of how they emerged and evolved after the mass extinction that wiped out dinosaurs and almost everything else 66 million years ago. That story is now coming to light, ...

Mapping crocodilian genomes

Dec 11, 2014

A Texas Tech University biologist led a team of more than 50 scientists who mapped the genomes of three crocodilians.

Recommended for you

Invasive species in the Great Lakes by 2063

1 hour ago

The Great Lakes have been invaded by more non-native species than any other freshwater ecosystem in the world. In spite of increasing efforts to stem the tide of invasion threats, the lakes remain vulnerable, ...

Baleen whales hear through their bones

1 hour ago

Understanding how baleen whales hear has posed a great mystery to marine mammal researchers. New research by San Diego State University biologist Ted W. Cranford and University of California, San Diego engineer ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.