Scientist's persistence sheds light on marine science riddle

September 07, 2006

PHILADELPHIA -- When he started compiling an online database of seashells 15 years ago, Dr. Gary Rosenberg did not envision that his meticulous record-keeping would eventually shed light on a 40-year-old evolutionary debate.

The debate involves the mechanism underlying the island rule: that small animals isolated on islands evolve to be larger than their mainland relatives, and large animals evolve to be smaller. In a paper to be published in September in the Journal of Biogeography, "The Island Rule and the Evolution of Body Size in the Deep Sea," Rosenberg and his co-authors apply the island rule to deep-sea animals using Rosenberg's detailed database of marine snails. They find a similar pattern: when species colonize the deep sea, large-bodied species become smaller and small-bodied species become larger.

"I've been building the Malacolog database for many years as a tool for research, summarizing information on the names and distributions of species of mollusks, but I had not anticipated asking this particular evolutionary question," said Rosenberg, Vice President for the Center for Systematic Biology and Evolution at The Academy of Natural Sciences, Philadelphia's natural history museum. "That means that the data entered in the system could not have been subconsciously biased toward this result. I hope there will be many more surprising results in the years to come." The database Malacolog (www.data.acnatsci.org/wasp) documents species of mollusks in the Western Atlantic, from Greenland to Antarctica.

Scientists have suggested several explanations for the evolution of body size in animals isolated on islands: reduced area, fewer predators, less competition, and resource limitation. "Only resource limitation clearly applies to deep-sea animals," said Rosenberg. "We know there is less food available in the deep sea than in shallow water, but the area of the deep sea is much larger. Also, the competitors and predators of a species often don't reach an island, but competition and predation in the deep sea can be intense. A lot more study needs to be done on the relative importance of these factors, but clearly resource limitation is a key factor in the evolution of size."
-end-
For more information see http://www.mbari.org/news/news_releases/2006/snailsize.html and http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-2699.2006.01545.x

The Academy is located at 1900 Benjamin Franklin Parkway and is open Monday through Friday from 10 a.m. to 4:30 p.m. and weekends until 5 p.m. Admission is $10 for adults, $8 for children ages 3-12, students with college I.D. and military personnel, $8.25 for seniors, and free for children under 3. The Academy of Natural Sciences is Philadelphia's natural history museum and a world leader in biodiversity and environmental research. The mission of the Academy is to create the basis for a healthy and sustainable planet through exploration, research and education.

Academy of Natural Sciences of Drexel University

Related Evolution Articles from Brightsurf:

Seeing evolution happening before your eyes
Researchers from the European Molecular Biology Laboratory in Heidelberg established an automated pipeline to create mutations in genomic enhancers that let them watch evolution unfold before their eyes.

A timeline on the evolution of reptiles
A statistical analysis of that vast database is helping scientists better understand the evolution of these cold-blooded vertebrates by contradicting a widely held theory that major transitions in evolution always happened in big, quick (geologically speaking) bursts, triggered by major environmental shifts.

Looking at evolution's genealogy from home
Evolution leaves its traces in particular in genomes. A team headed by Dr.

How boundaries become bridges in evolution
The mechanisms that make organisms locally fit and those responsible for change are distinct and occur sequentially in evolution.

Genome evolution goes digital
Dr. Alan Herbert from InsideOutBio describes ground-breaking research in a paper published online by Royal Society Open Science.

Paleontology: Experiments in evolution
A new find from Patagonia sheds light on the evolution of large predatory dinosaurs.

A window into evolution
The C4 cycle supercharges photosynthesis and evolved independently more than 62 times.

Is evolution predictable?
An international team of scientists working with Heliconius butterflies at the Smithsonian Tropical Research Institute (STRI) in Panama was faced with a mystery: how do pairs of unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again?

Predicting evolution
A new method of 're-barcoding' DNA allows scientists to track rapid evolution in yeast.

Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.

Read More: Evolution News and Evolution Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.