Comparative studies of leaf evolution in the California Chaparral
In an article published in the May 2004 issue of The American Naturalist, David D. Ackerly (Stanford University) compares the evolution of twelve lineages of the California Chaparral.
Which came first--trait or environment? This question lies at the heart of the study of adaptation by natural selection. In Mediterranean-type climates, many woody plants have small, tough, evergreen leaves (dubbed sclerophylls) which allow them to photosynthesize during the cool wet winters and survive the hot summer dry season. This paper presents the first comparative test of alternative hypotheses to explain these shared features. Did these traits evolve independently in different lineages, in response to the unique Mediterranean-type climate? Alternatively, did the traits evolve first in response to other factors, subsequently promoting the success of these lineages when summer drought conditions arose in the past few million years? Twelve independent plant lineages of the California chaparral were examined, using comparative methods that combine new phylogenetic information and statistical techniques. Only four of the twelve lineages showed the pattern expected if the leaves had evolved to suit the Mediterranean-type climate. In the other cases, the leaf traits appear to be ancestral characteristics of these lineages that predate the climatic conditions. These results, together with biogeographic and paleobotanical information, highlight the importance of ecological processes in concert with adaptive evolution in shaping the form
Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main
Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy