The European mole, equipped with its formidable digging shovels, can effortlessly tunnel through the earth. The same holds true for the Australian marsupial mole. Despite residing in vastly different regions, the two species.
A species is a group of living organisms that share a set of common characteristics and are able to breed and produce fertile offspring. The concept of a species is important in biology as it is used to classify and organize the diversity of life. There are different ways to define a species, but the most widely accepted one is the biological species concept, which defines a species as a group of organisms that can interbreed and produce viable offspring in nature. This definition is widely used in evolutionary biology and ecology to identify and classify living organisms.
Traditionally we’ve been taught the Earth has four primary layers. Though, a distinct change at depth suggests there’s another.
Fresh evidence concerning the possibility that Earth’s inner core has a separate inner core of its own was published in Nature Communications.
In the new study, Thanh-Son Phạm and Hrvoje Tkalčić from the Australian National University collated data from existing probes.
Rost-9D/iStock.
The latest findings suggest that the ‘innermost inner core’ may be an iron ball with a radius of about 650 kilometers inside the inner core. This could indicate a dramatic event in our planet’s history and improve our understanding of Earth’s genesis and evolution.
Scientists from The Ohio State University have a new theory about how the building blocks of life—the many proteins, carbohydrates, lipids and nucleic acids that compose every organism on Earth—may have evolved to favor a certain kind of molecular structure.
It has to do with a concept called chirality. A geometric property inherent to certain molecules, chirality can dictate a molecule’s shape, chemical reactivity, and how it interacts with other matter. Chirality is also sometimes referred to as handedness, as it can be best described as the dichotomy between our hands: Though they are not identical, the right and the left hand are mirror images of each other, and can’t be superimposed, or exactly overlaid on one another.
In the journal ACS Earth and Space Chemistry, researchers now propose a new model of how the molecules of life may have developed their “handedness.”
PBS Member Stations rely on viewers like you. To support your local station, go to http://to.pbs.org/DonateEons. ↓ More info below ↓ Our DNA holds thousands of dead genes and we’ve only just begun to unravel their stories. But one thing is already clear: we’re not just defined by the genes that we’ve gained over the course of our evolution, but also by the genes that we’ve lost along the way.
This video features this Paleogeographic Map: Scotese, C.R., 2019. Plate Tectonics, Paleogeography, and Ice Ages, YouTube video: https://youtu.be/UevnAq1MTVA.
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This process is no less relevant to humans than any other species in nature, but since our species is such an evolutionary newcomer, the extent of its influence — and how it might work today — is still difficult to pin down.
The challenge: A team of researchers in Greece and Ireland, led by Nikolaos Vakirlis at the Alexander Fleming Biomedical Sciences Research Center in Athens, argues that a key to understanding human evolution lies with short sequences of DNA named “open reading frames” (ORFs). These structures are small sections of the genome that encode tiny protein molecules — microproteins — which can perform a diverse range of crucial biological tasks, from regulating muscle performance to alerting cells to damaging stresses.
Due to their minuscule sizes, ORFs are notoriously difficult to study. Because of this, their full relevance has gone under the radar in mainstream genomics research until recently, and even today, they still aren’t considered to be proper genes in themselves. For Vakirlis’ team, this potential oversight masks the fact that the microproteins encoded by ORFs can develop their own de novo sequences over generations, which may eventually develop into new genes.
A new study has identified seven spider species previously unknown to science in the depths of Israeli caves, with the surprise finding that they are evolutionarily closer to arachnids found in southern Europe than to their neighbors at cave entrances in Israel.
The peer-reviewed research, published in the Molecular Phylogenetics and Evolution journal, was conducted by scientists from the Hebrew University in Jerusalem and the University of Madison-Wisconsin.
The study “has extensive scientific implications for uncovering the evolution of speciation in caves and the historical, geographic and climatic processes that occurred in Israel,” the Hebrew University said in a statement.
Interstellar dust captures a significant fraction of elements heavier than helium in the solid state and is an indispensable component both in theory and observations of galaxy evolution.
Dust emission is generally the primary coolant of the interstellar medium (ISM) and facilitates the gravitational collapse and fragmentation of gas clouds from which stars form, while altering the emission spectrum of galaxies from ultraviolet (UV) to far-infrared wavelengths through the reprocessing of starlight. However, the astrophysical origin of various types of dust grains remains an open question, especially in the early Universe.
Here we report direct evidence for the presence of carbonaceous grains from the detection of the broad UV absorption feature around 2175A˚ in deep near-infrared spectra of galaxies up to the first billion years of cosmic time, at a redshift (z) of ∼7. This dust attenuation feature has previously only been observed spectroscopically in older, more evolved galaxies at redshifts of z3. The carbonaceous grains giving rise to this feature are often thought to be produced on timescales of hundreds of millions of years by asymptotic giant branch (AGB) stars. Our results suggest a more rapid production scenario, likely in supernova (SN) ejecta.
University of Chicago scientists have discovered a new wrinkle in our understanding of how our genes work. The team, led by Chuan He, the UChicago John T. Wilson Distinguished Service Professor of Chemistry, Biochemistry and Molecular Biology, shed light on a longstanding puzzle involved in a common way our genes are modified that is known as RNA methylation.
Published Jan. 27 in Science, the finding could have implications for gene therapies for disease, as well as our picture of gene expression, development, and evolution.
For more than a decade, Chuan He’s laboratory has been focused on trying to unravel the puzzle of a phenomenon called RNA methylation, which we are increasingly understanding plays a key role in our bodies and lives—everything from cancer to PTSD to aging.
In quantum mechanics, the unitary nature of time evolution makes it intrinsically reversible, given control over the system in question. Remarkably, there have been several recent demonstrations of protocols for reverting unknown unitaries in scenarios where even the interactions with the target system are unknown. These protocols are limited by their probabilistic nature, raising the fundamental question of whether time-reversal could be performed deterministically. Here we show that quantum physics indeed allows for this by exploiting the non-commuting nature of quantum operators, and demonstrate a recursive protocol for two-level quantum systems with an arbitrarily high probability of success. Using a photonic platform, we achieve an average rewinding fidelity of over 95%. Our protocol, requiring no knowledge of the quantum process to be rewound, is optimal in its running time, and brings quantum rewinding into a regime of practical relevance.
Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
The brains of reptiles seemed to offer a clue. Not only are reptiles the closest living relatives of mammals, but their brains have a three-layered structure called a dorsal ventricular ridge, or DVR, with functional similarities to the neocortex.
The neocortex stands out as a stunning achievement of biological evolution. All mammals have this swath of tissue covering their brain, and the six layers of densely packed neurons within it handle the sophisticated computations and associations that produce cognitive prowess. Since no animals other than mammals have a neocortex, scientists have wondered how such a complex brain region evolved.
Now, however, by analyzing molecular details invisible to the human eye, scientists have refuted that view. By looking at patterns of gene expression in individual brain cells, researchers at Columbia University showed that despite the anatomical similarities, the neocortex in mammals and the DVR in reptiles are unrelated. Instead, mammals seem to have evolved the neocortex as an entirely new brain region, one built without a trace of what came before it. The neocortex is composed of new types of neurons that seem to have no precedent in ancestral animals.
