In the city, frogs do not feel as comfortable as in the wild nature because of dirty water, a lack of food, and dangers at every turn. That is why the life of frogs in urban areas is shorter. However, they do not leave these habitats, but adapt to them. Apparently, there are two ways to adapt: either become more tolerant or increase the number of progeny.
Every spring from 1998 to 2001, Elena A. Severtseva and her colleagues from the Biological Faculty of the Moscow State University studied the spawn of two frog species (Rana temporaria and Rana arvalis) most common in Moscow parks and ponds. The scientists counted the number of layings and the quantity of eggs in each laying and measured the diameter of eggs and their yolks using a microscope.
In average, Moscow frogs have smaller eggs than their sisters in the countryside, but each urban frog lays several hundred eggs more than the rural one. The egg diameter is about one millimetre, and the difference between egg sizes in the city and suburbs constitutes several decimal fractions of millimetre, but that is sufficient to gain in quantity. At the same time, urban conditions do not change the yolk size in relation to that of the whole egg; sometimes yolks of Moscow frogs are even larger. Therefore, the embryo has a sufficient food supply to grow into the tadpole, though tadpoles from small eggs need a longer time for development.
Alexander Barne | alphagalileo
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22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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