Navigation Links
Extinction runs in the family
Date:8/8/2009

Global calamities like the one that doomed most dinosaurs forever alter the varieties of life found on Earth, but new research shows that it doesn't take a catastrophe to end entire lineages. An analysis of 200 million years of history for marine clams found that vulnerability to extinction runs in evolutionary families, even when the losses result form ongoing, background rates of extinction.

"Biologists have long suspected that the evolutionary history of species and lineages play a big role in determining their vulnerability to extinction, with some branches of the tree of life being more extinction-prone than others," said Kaustuv Roy, a biology professor at the University of California, San Diego, noting that human activities threaten some evolutionary lineages of living vertebrates more than others. "Now we know that such differential loss is not restricted to extinctions driven by us but is a general feature of the extinction process itself."

Roy and colleagues Gene Hunt of the Smithsonian Institution and David Jablonski of the University of Chicago report their findings in Science this week.

Their study focused on marine bivalves such as clams, oysters, mussels, and scallops, whose tough shells fossilize well to provide a rich record for study. By analyzing a global database of bivalve fossils stretching from the Jurassic Period to the present, the researchers noted when each genus disappeared and whether their relatives disappeared at the same time.

On average, closely related clusters of clams vanished together more often than expected by chance.

"Both background extinctions, which represent most extinctions in the history of life, and mass extinctions tend to be clumped into particular evolutionary lineages," Jablonski said.

The effect was particularly strong during the mass extinction at the end of the Cretaceous period, when clam lineages with the highest 'background' rates of extinction during more normal times were hardest hit. Three families with the highest background rates disappeared entirely. Two others, with rates more than twice the median, suffered heavy losses and have not recovered to this day.

"Big extinctions have a filtering effect. They tend to preferentially cull the more vulnerable lineages, leaving the resistant ones to proliferate afterwards," Hunt said.

When extinctions are scattered randomly across the evolutionary tree, the breadth of evolutionary history remains represented among living things, even when many species are lost. Clumped extinctions do the opposite, disproportionately removing the deeper history.

"Extinctions in the past and presumably in the future will lop off chunks of evolutionary trees, not just prune the trees and leave most of the history intact," Jablonski said.

The message for conservation is to focus efforts on vulnerable lineages, the authors say. To preserve the full spectrum of evolutionary history found among living things today, the most fragile families will need careful protection.

Even relatively low levels of threat could eliminate large limbs, Roy said. "If you have whole lineages more vulnerable than others, then very soon, even with relatively moderate levels of extinction, you start to lose a lot of evolutionary history."


'/>"/>

Contact: Kaustuv Roy
kroy@ucsd.edu
University of California - San Diego
Source:Eurekalert

Related biology news :

1. Surviving mass extinction by leading a double life
2. Evidence of the Lost World -- did dinosaurs survive the end Cretaceous extinctions?
3. Study shows competition, not climate change, led to Neanderthal extinction
4. Current mass extinction spurs major study of which plants to save
5. Geologist who linked cosmic strike to dinosaurs extinction takes top prize
6. UGA study reveals ecosystem-level consequences of frog extinctions
7. Extinction by asteroid a rarity
8. Mass extinctions and the evolution of dinosaurs
9. Study of islands reveals surprising extinction results
10. A recipe for saving the worlds oceans from an extinction crisis
11. Extinction most likely for rare trees in the Amazon rainforest
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/3/2017)... Feb. 3, 2017  Texas Biomedical Research Institute announced that ... Larry Schlesinger as the Institute,s new President and CEO. ... May 31, 2017. He is currently the Chair of the ... Center for Microbial Interface Biology at Ohio State University. ... new President and CEO of Texas Biomed," said Dr. ...
(Date:2/2/2017)... , Feb. 1, 2017  Central to its ... meaningful advances worldwide, The Japan Prize Foundation today ... who have pushed the envelope in their respective ... Communication. Three scientists are being recognized with the ... that not only contribute to the advancement of ...
(Date:1/26/2017)...  Crossmatch, a leading provider of security and identity ... combatting fraud, waste and abuse in assistance operations around ... on Disaster Relief conference in Panama City ... and foreign assistance organizations throughout Latin America ... a largely unacknowledged problem in the foreign assistance and ...
Breaking Biology News(10 mins):
(Date:2/23/2017)... YORK , Feb. 23, 2017 ... digital health company, and Digital Noema Telehealth ... remote patient monitoring, announce they are partnering to ... DN Telehealth maximizes collaboration compatibility for its ... beyond a physical clinical setting to include fully ...
(Date:2/23/2017)... 23, 2017 /PRNewswire/ - The Fight Against Cancer Innovation ... (OICR) are pleased to report that Fusion Pharmaceuticals Inc. ... Johnson & Johnson Innovation – JJDC, Inc. (JJDC) as ... HealthCap, TPG Biotechnology Partners, and Genesys Capital, as well ... ...
(Date:2/23/2017)... Feb. 23, 2017  Seattle,s upscale Capitol Hill neighborhood, with its ... place for a head lice treatment salon to set up ... Tuscan restaurant and a French bistro on E Madison Ave, ... aren,t just any old lice clinic, we pride ourselves on ... and release some of the stigma associated with lice. Everyone ...
(Date:2/23/2017)... (PRWEB) , ... February 23, ... ... Inc., announced today that in a published evaluation of multiple immunoassay-based threat ... U.S. Department of Energy Laboratory, PathSensors’ CANARY® biosensor threat detection technology was ...
Breaking Biology Technology: