Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Pressured by predators, lizards see rapid shift in natural selection

Countering the widespread view of evolution as a process played out over the course of eons, evolutionary biologists have shown that natural selection can turn on a dime -- within months -- as a population's needs change.

In a study of island lizards exposed to a new predator, the scientists found that natural selection dramatically changed direction over a very short time, within a single generation, favoring first longer and then shorter hind legs.

The findings, by Jonathan B. Losos of Harvard University and colleagues, are detailed this week in the journal Science. Losos did much of the work before joining Harvard earlier this year from Washington University in St. Louis.

"Because of its epochal scope, evolutionary biology is often caricatured as incompatible with controlled experimentation," says Losos, professor of organismic and evolutionary biology in Harvard's Faculty of Arts and Sciences and curator in herpetology at the Harvard Museum of Comparative Zoology. "Recent work has shown, however, that evolutionary biology can be studied on short time scales and that predictions about it can be tested experimentally. We predicted, and then demonstrated, a reversal in the direction of natural selection acting on limb length in a population of lizards."

... more about:
»Anolis »Biology »Evolutionary »Predator »lizard

Losos and colleagues studied populations of the lizard Anolis sagrei on minuscule islands, or cays, in the Bahamas. They introduced to six of these cays a larger, predatory lizard (Leiocephalus carinatus) commonly found on nearby islands and known as a natural colonizer of small cays. The scientists kept six other control cays predator-free and exhaustively counted, marked, and measured lizards on all 12 isles.

Anolis sagrei spends much of its time on the ground, but previous research has shown that when a terrestrial predator is introduced, these lizards take to trees and shrubs, becoming increasingly arboreal over time. Losos and his colleagues hypothesized that immediately following a predator's arrival, longer-legged -- and hence faster-running -- Anolis lizards would be favored to elude capture. However, as the lizards grew ever more arboreal in habitat, the scientists projected that natural selection would begin to favor shorter limbs, which are better suited to navigating narrow branches and twigs.

Their hypothesis was borne out. Six months after the introduction of the predator, Losos found that the Anolis population had dropped by half or more on the islands with the predators, and in comparison to the lizards on the predator-free islands, long legs were more strongly favored: Survivors had longer legs relative to non-survivors. After another six months, during which time the Anolis lizards grew increasingly arboreal, selective pressures were exactly the opposite: Survivors were now characterized by having shorter legs on the experimental islands as compared to the control islands.

The behavioral shift from the ground to higher perches apparently caused this remarkable reversal, Losos says, adding that behavioral flexibility may often drive extremely rapid shifts in evolution.

"Evolutionary biology is by its nature an historical science, but the combination of microevolutionary experimentation and macroevolutionary historical analysis can provide a rich understanding about the genesis of biological diversity," the researchers write.

Steve Bradt | EurekAlert!
Further information:

Further reports about: Anolis Biology Evolutionary Predator lizard

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

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...

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

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>