There’s an intriguing possibility that the emergence of conscious life is not just a coincidence, but an inevitable outcome of cosmic evolution.
Category: evolution – Page 25
A recent study suggests that the near-collapse of the geomagnetic field during the Ediacaran period may have played a role in the diversification of life on Earth. This coincided with a significant increase in oxygen levels, which could have provided a favorable environment for the development of new species. The ultra-weak geomagnetic field may have allowed for increased solar radiation, leading to higher oxygen production through photosynthesis. This discovery sheds light on the potential impact of Earth’s magnetic field on the evolution of life.
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.
“These results match predictions made from skeletal anatomy, providing the first molecular evidence for the evolutionary relationships of a non-avian dinosaur,” says co-author Chris Organ, a postdoctoral researcher in organismic and evolutionary biology at Harvard University.
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?
A superbeing with powers beyond comprehension? A mutated oddity far removed from our idea of humanity? Or perhaps nothing but decaying remains left in the wake of our extinction?
Scientists and sci-fi authors have long speculated on what our future selves will look like — and as technology advances, our species might evolve much faster than natural selection would typically allow. So, for this entry into the archive, we’ll explore posthuman scenarios from the absurd to the frighteningly plausible — and meet the many possible successors to humankind…
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.