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Categories: Biology: Evolutionary, Geoscience: Geology

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Researchers investigated how the jaw shape of sharks has changed over the course of evolution. Their conclusion: in the most widespread shark species, the jaws show relatively little variation in shape over millions of years; most variable jaws were found for deep-sea sharks.

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Approximately 700,000 years ago, a 'warm ice age' permanently changed the climate cycles on Earth. During this exceptionally warm and moist period, the polar glaciers greatly expanded. A research team identified this seemingly paradoxical connection. The shift in the Earth's climate represents a critical step in our planet's later climate development.

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A research team, composed of climatologists and an astronomer, have used an improved computer model to reproduce the cycle of ice ages (glacial periods) 1.6 to 1.2 million years ago. The results show that the glacial cycle was driven primarily by astronomical forces in quite a different way than it works in the modern age. These results will help us to better understand the past, present, and future of ice sheets and the Earth's climate.

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Scientists have discovered where butterflies originated and which plants the first butterflies relied on for food. To reach these conclusions, researchers created the world's largest butterfly tree of life, which they used as a guide to trace trace the evolution of butterflies through time in a four-dimensional puzzle that led back to North and Central America.

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Scientists have precisely identified base pairs of the human genome that remained consistent over millions of years of mammalian evolution, and which play a crucial role in human disease. The team analyzed the genomes of 240 mammals, including humans and identified base pairs that were 'constrained' -- meaning they remained generally consistent -- across mammal species over the course of evolution. The most constrained base pairs in mammals were over seven times more likely to be causal for human disease and complex trait, and over 11 times more likely when researchers looked at the most constrained base pairs in primates alone.

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An international team has reconstructed the evolution of groundwater in the Great Basin, USA -- one of the driest regions on Earth -- up to 350,000 years into the past with unprecedented accuracy. The results shed new light on the effects of climate change on water supply and provide important insights for the sustainable use of groundwater resources.

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Bacteria can rapidly evolve resistance to antibiotics by adapting special pumps to flush them out of their cells, according to new research. Antimicrobial resistance is a growing problem of global significance. The rise of resistant 'superbugs' threatens our ability to use antimicrobials like antibiotics to treat and prevent the spread of infections caused by microorganisms. It is hoped that the findings will improve how antibiotics are used to help prevent further spread of antimicrobial resistance.

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Throughout the ocean, billions upon billions of plant-like microbes make up an invisible floating forest. As they drift, the tiny organisms use sunlight to suck up carbon dioxide from the atmosphere. Collectively, these photosynthesizing plankton, or phytoplankton, absorb almost as much CO2 as the world’s terrestrial forests. A measurable fraction of their carbon-capturing muscle comes from Prochlorococcus — an emerald-tinged free-floater that is the most abundant phytoplankton in the oceans today. New research suggests the microbe's ancient coastal ancestors colonized the ocean by rafting out on chitin particles.

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A new study finds that early human species adapted to mosaic landscapes and diverse food resources, which would have increased our ancestor's resilience to past shifts in climate.

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Around 500 million years ago life in the oceans rapidly diversified. In the blink of an eye -- at least in geological terms -- life transformed from simple, soft-bodied creatures to complex multicellular organisms with shells and skeletons. Now, research has shown that the diversification of life at this time also led to a drastic change in the chemistry of Earth's crust -- the uppermost layer we walk on and, crucially, the layer which provides many of the nutrients essential to life.

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Over 3,000 generations of laboratory evolution, researchers watched as their model organism, 'snowflake yeast,' began to adapt as multicellular individuals. In new research, the team shows how snowflake yeast evolved to be physically stronger and more than 20,000 times larger than their ancestor. Their study is the first major report on the ongoing Multicellularity Long-Term Evolution Experiment (MuLTEE), which the team hopes to run for decades.

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Comparing individual cells across corn, sorghum, and millet reveals evolutionary differences among these important cereal crops, according to a new study. The findings bring researchers closer to pinpointing which genes control important agricultural traits such as drought tolerance, which will help scientists faced with a changing climate adapt crops to drier environments.

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Rhinoceros belong to a mammalian order called odd-toed ungulates that also include horses and tapirs. They are found in Africa and Asia. Until recently, evidence suggested that throughout their evolutionary history, gamma-retroviruses such as Murine leukemia virus had not colonized their genomes, unlike most other mammalian orders. The colonization process is called retroviral endogenization and has resulted in most mammalian genomes being comprised of up to ten percent retroviral like sequences.

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Researchers have developed a DNA enzyme -- or DNAzyme -- that can distinguish between two RNA strands inside a cell and cut the disease-associated strand while leaving the healthy strand intact. This breakthrough 'gene silencing' technology could revolutionize the development of DNAzymes for treating cancer, infectious diseases and neurological disorders.

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Birds across the Americas are getting smaller and longer-winged as the world warms, and the smallest-bodied species are changing the fastest.

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Researchers have proposed a new model for the evolution of higher brain functions and behaviors in the Hymenoptera order of insects. The team compared the Kenyon cells, a type of neuronal cell, in the mushroom bodies (a part of the insect brain involved in learning, memory and sensory integration) of 'primitive' sawflies and sophisticated honey bees. They found that three diverse, specialized Kenyon cell subtypes in honey bee brains appear to have evolved from a single, multifunctional Kenyon cell-subtype ancestor. In the future, this research could help us better understand the evolution of some of our own higher brain functions and behaviors.

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New research deepens the understanding of Earth's crust by testing and ultimately eliminating one popular hypothesis about why continental crust is lower in iron and more oxidized compared to oceanic crust. The iron-poor composition of continental crust is a major reason why vast portions of the Earth's surface stand above sea level as dry land, making terrestrial life possible today. The study uses laboratory experiments to show that the iron-depleted, oxidized chemistry typical of Earth's continental crust likely did not come from crystallization of the mineral garnet, as a popular explanation proposed in 2018.

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Most chromosomes have been around for millions of years. Now, researchers have revealed the dynamics of a new, very young chromosome in fruit flies that is similar to chromosomes that arise in humans and is associated with treatment-resistant cancer and infertility. The findings may one day lead to developing more targeted therapies for treating these conditions.

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Researchers have proposed a new evolutionary model for the origin of a kingdom of viruses called Bamfordvirae, suggesting a billion-years evolutionary arms race between two groups within this kingdom and their hosts.

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According to researchers, a new analysis of an 80-million-year-old permineralized pollen cone found in the Campanian Holz Shale formation located in Silverado Canyon, California, offers a more accurate cycad natural history -- one where the plants diversified during the Cretaceous.