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Category: Biology

Only a tiny fraction of the genes inside our bodies are human

Only a tiny fraction of the genes inside our bodies are human

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James Gallagher writes: Prof Rob Knight, from University of California San Diego, told the BBC: “You’re more microbe than you are human.” Originally it was thought our cells were outnumbered 10 to one. “That’s been refined much closer to one-to-one, so the current estimate is you’re about 43% human if you’re counting up all the cells,” he says. But genetically we’re even more outgunned. The human genome – the full set of genetic instructions for a human being – is…

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Burning coal may have caused Earth’s worst mass extinction

Burning coal may have caused Earth’s worst mass extinction

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Dana Nuccitelli writes: Recently, geologist Dr Benjamin Burger identified a rock layer in Utah that he believed might have formed during the Permian and subsequent Triassic period that could shed light on the cause of the Great Dying [the Earth’s deadliest mass extinction 252 million years ago]. During the Permian, Earth’s continents were still combined as one Pangea, and modern day Utah was on the supercontinent’s west coast. Samples from the end-Permian have been collected from rock layers in Asia,…

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How Lyme disease the first epidemic of climate change

How Lyme disease the first epidemic of climate change

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Mary Beth Pfeiffer writes: In the tally of species that will evolve or perish as temperatures rise, now consider the moose. The lumbering king of the deer family, known for antlers that can span six feet like giant outstretched fingers, the moose faces a litany of survival threats, from wolves and bears to brain worms and liver fluke parasites. But in the late 1990s in many northern states and Canada, something else began to claim adult cows and bull moose…

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The interstitium, the largest organ we never knew we had

The interstitium, the largest organ we never knew we had

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Tanya Basu writes: What is an organ? Anatomy textbooks are rather fuzzy about what defines an “organ,” requiring one to have primary tissue—parenchyma—and “sporadic” tissue, called stroma, which can be nerves, vessels, and other connective tissue. Organs are the necessary building blocks of organisms (hence, the name), and can be gigantic or microscopic. So long as cells clump together to form tissues, and these tissues organize themselves into organs that perform specific functions in the survival of an organism, that…

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How new data is transforming our understanding of place cells — the brain’s GPS

How new data is transforming our understanding of place cells — the brain’s GPS

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Adithya Rajagopalan writes: The first pieces of the brain’s “inner GPS” started coming to light in 1970. In the laboratories of University College London, John O’Keefe and his student Jonathan Dostrovsky recorded the electrical activity of neurons in the hippocampus of freely moving rats. They found a group of neurons that increased their activity only when a rat found itself in a particular location. They called them “place cells.” Building on these early findings, O’Keefe and his colleague Lynn Nadel…

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3.5 billion-year-old fossils challenge ideas about early life on Earth

3.5 billion-year-old fossils challenge ideas about early life on Earth

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Rebecca Boyle writes: In the arid, sun-soaked northwest corner of Australia, along the Tropic of Capricorn, the oldest face of Earth is exposed to the sky. Drive through the northern outback for a while, south of Port Hedlund on the coast, and you will come upon hills softened by time. They are part of a region called the Pilbara Craton, which formed about 3.5 billion years ago, when Earth was in its youth. Look closer. From a seam in one…

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Land degradation by human activities pushing Earth into sixth mass extinction and undermining well-being of 3.2 billion people

Land degradation by human activities pushing Earth into sixth mass extinction and undermining well-being of 3.2 billion people

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  Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES): Worsening land degradation caused by human activities is undermining the well-being of two fifths of humanity, driving species extinctions and intensifying climate change. It is also a major contributor to mass human migration and increased conflict, according to the world’s first comprehensive evidence-based assessment of land degradation and restoration. The dangers of land degradation, which cost the equivalent of about 10% of the world’s annual gross product in 2010 through…

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DNA from more than 900 ancient people trace the prehistoric migrations of our species

DNA from more than 900 ancient people trace the prehistoric migrations of our species

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Carl Zimmer writes: David Reich wore a hooded, white suit, cream-colored clogs, and a blue surgical mask. Only his eyes were visible as he inspected the bone fragments on the counter. Dr. Reich, a geneticist at Harvard Medical School, pointed out a strawberry-sized chunk: “This is from a 4,000-year-old site in Central Asia — from Uzbekistan, I think.” He moved down the row. “This is a 2,500-year-old sample from a site in Britain. This is Bronze Age Russian, and these…

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Are we smart enough to know how smart animals are?

Are we smart enough to know how smart animals are?

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Frans de Waal asks: are we smart enough to know how smart animals are? Just as attitudes of superiority within segments of human culture are often expressions of ignorance, humans collectively — especially when subject to the dislocating effects of technological dependence — tend to underestimate the levels of awareness and cognitive skills of creatures who live mostly outside our sight. This tendency translates into presuppositions that need to be challenged by what de Waal calls his “cognitive ripple rule”:…

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Why moths learn so much faster than machines

Why moths learn so much faster than machines

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Technology Review reports: One of the curious features of the deep neural networks behind machine learning is that they are surprisingly different from the neural networks in biological systems. While there are similarities, some critical machine-learning mechanisms have no analogue in the natural world, where learning seems to occur in a different way. These differences probably account for why machine-learning systems lag so far behind natural ones in some aspects of performance. Insects, for example, can recognize odors after just…

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Pistachio trees ‘talk’ to their neighbours, reveals statistical physics

Pistachio trees ‘talk’ to their neighbours, reveals statistical physics

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Philip Ball writes: The number of nuts on pistachio trees in any given year could be explained with a model from statistical physics that is normally used to study magnetic materials. That is according to researchers led by Alan Hastings, a mathematical ecologist from the University of California, Davis, who have used the “Ising model” to analyse the yields of pistachio trees in one particular orchard in California. Their work explains why the orchard does not always have a uniformly…

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We’re killing our lakes and oceans

We’re killing our lakes and oceans

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Eelco Rohling and Joseph Ortiz write: On January 5, 2018, a paper published in the journal Science delivered a sobering message: The oxygenation of open oceans and coastal seas has been steadily declining during the past half century. The volume of ocean with no oxygen at all has quadrupled, and the volume where oxygen levels are falling dangerously low has increased even more. We’re seeing the same thing happen in major lakes. The main culprits are warming and — especially…

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Plants, people, and decision-making

Plants, people, and decision-making

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Laura Ruggles writes: Plants are not simply organic, passive automata. We now know that they can sense and integrate information about dozens of different environmental variables, and that they use this knowledge to guide flexible, adaptive behaviour. For example, plants can recognise whether nearby plants are kin or unrelated, and adjust their foraging strategies accordingly. The flower Impatiens pallida, also known as pale jewelweed, is one of several species that tends to devote a greater share of resources to growing…

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