Ever since Charles Darwin published his landmark theory of how species evolve, biologists have been fascinated with the intricate mechanisms that make evolution possible.
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Putting more meat on the theory that dinosaurs’ closest living relatives are modern-day birds, molecular analysis of a shred of 68-million-year-old Tyrannosaurus rex protein — along with that of 21 modern species — confirms that dinosaurs share common ancestry with chickens, ostriches, and to a lesser extent, alligators.
The work, published this week in the journal Science, represents the first use of molecular data to place a non-avian dinosaur in a phylogenetic tree that traces the evolution of species. The scientists also report that similar analysis of 160,000-to 600,000-year-old collagen protein sequences derived from mastodon bone establishes a close phylogenetic relationship between that extinct species and modern elephants.
Continue reading “Molecular analysis confirms T. Rex’s evolutionary link to birds” »
We discuss a perturbative and non-instantaneous reheating model, adopting a generic post-inflationary scenario with an equation of state w. In particular, we explore the Higgs boson-induced reheating, assuming that it is achieved through a cubic inflaton-Higgs coupling ϕ|H|2. In the presence of such coupling, the Higgs doublet acquires a ϕ-dependent mass and a non-trivial vacuum–expectation–value that oscillates in time and breaks the Standard Model gauge symmetry. Furthermore, we demonstrate that the non-standard cosmologies and the inflaton-induced mass of the Higgs field modify the radiation production during the reheating period. This, in turn, affects the evolution of a thermal bath temperature, which has remarkable consequences for the ultraviolet freeze-in dark matter production.
Daniel Dennett, who died in April at the age of 82, was a towering figure in the philosophy of mind. Known for his staunch physicalist stance, he argued that minds, like bodies, are the product of evolution. He believed that we are, in a sense, machines—but astoundingly complex ones, the result of millions of years of natural selection.
Dennett wrote more than a dozen books, some of them aimed at a scholarly audience but many of them directed squarely at the inquisitive non-specialist—including bestsellers like Consciousness Explained, Breaking the Spell, and Darwin’s Dangerous Idea. Reading his works, one gets the impression of a mind jammed to the rafters with ideas. As Richard Dawkins put it in a blurb for Dennett’s last book, a memoir titled I’ve Been Thinking: “How unfair for one man to be blessed with such a torrent of stimulating thoughts.”
The big bang is the model that describes the birth and evolution of the universe. But where did the term come from? What does it actually mean?
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Research has uncovered important new insights into the evolution of oxygen, carbon, and other vital elements over the entire history of Earth – and it could help assess which other planets can develop life, ranging from plants to animals and humans.
The study, published today in Nature Geoscience and led by a researcher at the University of Bristol, reveals for the first time how the build up of carbon-rich rocks has accelerated oxygen production and its release into the atmosphere.
Until now the exact nature of how the atmosphere became oxygen-rich has long eluded scientists and generated conflicting explanations.
Humanity will change. Or be replaced. Or go extinct. An exploration of the many potential posthuman offspring of humankind, from the biological to the artificial.
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What do you imagine when I say the future of human evolution?
Charles Darwin and his followers postulated that random accidental mutations of small effect plus natural selection over long periods would provide sufficient hereditary variation to explain biological diversity. Research since the middle of the twentieth century has unexpectedly shown that living organisms possess many different means of altering their genomes biologically, and these processes have been validated by DNA sequence analysis. In addition, the biological process of interspecific hybridization has become recognized as a major source of rapid speciation and genome amplification. Thus, it is time to shift our basic concept of evolutionary variation from the traditional model of slow change from non-biological sources to a fully biological model of rapid genome reorganization stimulated by challenges to reproduction.
Introduction
In Western society prior to the Enlightenment, there was little disagreement about the origins of biological diversity: it resulted from divine creation of an unchanging panorama of plant and animal species, as explained in Genesis. No thought was given to the idea that living organisms could change their fundamental natures. Even a scientist dedicated to analyzing the nature and classification of life forms, Carl Linnaeus (1707−1778), and one who documented the extinction of fossil organisms, Georges Cuvier (1769−1832), both believed in the fixity of species.
We’re now adding a new location and entering into the next stage of the program’s evolution. Later this year, drone deliveries are coming to the West Valley of the Phoenix Metro Area in Arizona.
With this new location, we’ll be fully integrated into Amazon’s delivery network, meaning, for the first time, drones will deploy from facilities next to our Same-Day Delivery site in Tolleson. These smaller sites are hybrid—part fulfillment center, part delivery station. They allow us to fulfill, sort, and deliver products all from one site so we can get packages out to our customers even quicker. Our Same-Day Delivery sites are situated close to the large metro areas they serve, which means customers get their orders faster. And with connections to the larger Amazon fulfillment centers nearby, we are able to offer Same-Day Delivery on millions of items.
We’re currently working with the Federal Aviation Administration (FAA) and local officials in Tolleson to obtain all necessary permissions to conduct these deliveries in Tolleson. Once we’ve received all the necessary approvals, we’ll begin reaching out to customers in the West Valley so they can receive drone deliveries when the service goes live later this year.
Scientists champion global genomic surveillance using the latest technologies and a ‘One Health’ approach to protect against novel pathogens like avian influenza and antimicrobial resistance, catching epidemics before they start.
The COVID-19 pandemic turned the world upside down. In fighting it, one of our most important weapons was genomic surveillance, based on whole genome sequencing, which collects all the genetic data of a given microorganism. This powerful technology tracked the spread and evolution of the virus, helping to guide public health responses and the development of vaccines and treatments.
But genomic surveillance could do much more to reduce the toll of disease and death worldwide than just protect us from COVID-19. Writing in the journal Frontiers in Science, an international collective of clinical and public health microbiologists from the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) calls for investment in technology, capacity, expertise, and collaboration to put genomic surveillance of pathogens at the forefront of future pandemic preparedness.
