Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Biologist’s new experiment may vindicate Darwin


Charles Darwin, the founder of the modern theory of evolution, was an avid proponent of sympatric speciation, the idea that a single species need not be geographically divided in order to evolve into two separate species. In the mid-20th century, however, certain vocal scientists convinced the scientific community that geographically isolating two halves of a population was a necessary factor in creating a new species. It wasn’t until the last few decades that modern biologists began to reexamine Darwin’s ideas to discover that he may have been quite right all along. Now the theory behind one such idea is undergoing its most exhaustive test yet at the University of Rochester.

James D. Fry, assistant professor of biology, is running fruit flies through a series of tests to see if a few, subtle changes in the flies’ environment could be enough to trigger the creation of a new species.

"For a long time there has been speculation that small differences in the environment coupled with small differences in the way organisms behave could lead to speciation without any other external factors," says Fry. "This is this first time this idea has been tested in the same way it might happen in nature. If we can get the flies to start exhibiting changes with these tests, then it’s very likely that it can happen easily in nature."

Similar trials tested speciation mechanisms that worked well in theory, but may not be very applicable to insects in the wild. Those experiments gave a choice of several of habitats, with only those flies choosing the most extreme habitats allowed to breed. This method imposes selection directly on the trait of habitat choice by weeding out those organisms that choose "incorrect" ones, whereas Fry’s experiment is designed specifically so that no fly’s habitat choice will automatically exclude it from breeding--a design he feels more closely approximates the natural world.

Fry lets the flies group together in a sort of lobby area before letting them out via two tunnels. One tunnel leads to a bright area and the other toward a darker area. Inevitably, some of the flies choose to go to the light and others to the darkness. Once in their new light or dark homes, Fry inspects the number of the bristles on each fly, acting like a sort of natural selection by removing sparsely bristled flies from the bright area and more densely bristled flies from the darker one. The bristles act as a marker that Fry can track over generations. The leftover flies in each habitat are then allowed to reproduce before being sent back to the lobby to make a habitat choice again.

Initially, Fry does not expect much correlation between bristle number and the individual’s preference for light or dark abodes, but after several dozen generations over the course of several months he expects to see that flies with fewer bristles tend toward the dark while multi-bristled ones head for the light. A fly that prefers the dark and happens to have few bristles will survive Fry’s "weeding out" process and will reproduce with another few-bristled dark-lover. Genetics being what they are, the couple is more likely to have offspring with fewer bristles and a hankering for a darker habitat. The couple may very well have some multi-bristlers or light-lovers, but those will never be able to reproduce because once everyone is sent back to the lobby, those offspring will head toward the habitat where their number of bristles will mark them for removal. The bristle number is being used as a sort of surrogate for a trait that might affect survival in nature, such as the camouflage coloring of a moth. This survivability variable was missing in previous studies since in them the only thing being selected for or against was the choice of habitat itself.

Eventually, after months of weeding and 50 to 60 generations, Fry hopes to see a correlation between brightness preference and bristle number. Already, a weak correlation is appearing after just 12 generations. If he finds that all the flies moving toward the light have few bristles, he’ll be fairly sure that they will never again mate with the dark-loving flies. If left in this artificial ecosystem, the flies will likely develop into completely separate species.

This kind of speciation mechanism relies on small differences in the environment that interact with the small differences in the behavior of individuals of a species. Individual preferences and small environmental differences are far more common than large geologic events such as floods or rising mountain ranges that are necessary for full geologic isolation so this model, if it is successful, could give biologists a new tool when piecing together the history of a species.

"Speciation without geologic isolation has been tested before, but the tests weren’t all that applicable to nature," says Fry. "If this test shows two separate populations of flies forming, it would add a new model of speciation to evolution--one that describes bugs, which account for a quarter of the species on earth."

Jonathan Sherwood | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht ‘Farming’ bacteria to boost growth in the oceans
24.10.2016 | Max-Planck-Institut für marine Mikrobiologie

nachricht Calcium Induces Chronic Lung Infections
24.10.2016 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Oasis of life in the ice-covered central Arctic

24.10.2016 | Earth Sciences

‘Farming’ bacteria to boost growth in the oceans

24.10.2016 | Life Sciences

Light-driven atomic rotations excite magnetic waves

24.10.2016 | Physics and Astronomy

More VideoLinks >>>