2018 Stories
A country weed with city problems
If you live in North America, Europe, Asia, or almost any other temperate environment, you’ve probably seen Trifolium repens, an unassuming white clover popular with bees and unpopular with homeowners fixated on a perfect lawn. Native to Europe and Asia, this hardy species has spread all over the globe with an assist from humans who introduced it to new environments for livestock to graze on. But T. repens didn’t stay put in those rural farmlands: as the clover was advancing into any available grassy area, cities were encroaching on surrounding countryside. Today, white clover is everywhere — in bucolic fields, urban parks, and the sidewalk cracks of bustling metropolises. Since this country weed has taken up life in the big city, it has also experienced a pronounced evolutionary change…
Read more »And the Nobel goes to…evolution!
Last month, the Royal Swedish Academy of Science announced that this year’s Nobel Prize in Chemistry would go to Frances Arnold (currently at the California Institute of Technology), George Smith (University of Missouri), and Gregory Winter (MRC Laboratory of Molecular Biology, Cambridge, UK) for innovations that are being used to fine-tune manufacturing processes to reduce environmental harm, produce new renewable fuels, and build pharmaceuticals that harness the power of the body’s own immune system to fight disease. Their inspiration? Evolution by natural selection.
Read more »Standing on two feet or four: Switchbacks in dino evolution
Last month, researchers announced the discovery of an enormous dinosaur in South Africa. Ledumahadi mafube (which means “giant thunderclap at dawn” in the Sotho language) weighed as much as two elephants and lived around 200 million years ago. Scientists were surprised to find that such a big dinosaur was so ancient. L. mafube was the largest dinosaur known from its time, and the closely related sauropods (true behemoths which grew to be seven times as large as L. mafube and included the largest land animals ever) achieved their massive sizes much later. Evidence also suggests that this new dinosaur walked on four legs — a finding that highlights the fact that evolution represents a blossoming of diversity, not a linear march of “advancement” along a set track.
Read more »Why vaccines work when drugs no longer do
For the past two years, drug-resistant typhoid has plagued Pakistan and is soon expected to make its way around the world. Typhoid fever is contracted through food or water contaminated with Salmonella Typhi. The vomiting, fever, and headaches caused by the bacterium are rarely fatal when treated — but now doctors are wondering how much longer our drugs will work against the pathogen. The strain from Pakistan resists five different kinds of antibiotics. Only one oral antibiotic, azithromycin, can still combat these bacteria, and scientists worry that resistance to this drug as well is just around the corner. Interestingly, a key weapon in the fight against drug resistant typhoid is vaccination. Salmonella Typhi evolves resistance to antibiotics quickly (in some cases, within two years), but has yet to evolve resistance to our vaccines, despite over a century of use.
Read more »Evolution experiments on isolated islands
The Hawaiian Islands offer sun-loving tourists a chance to get away from it all in a peaceful paradise, and it is these same qualities that make the islands the perfect place to study evolution. Hawaiian fruit flies, silversword plants, and honeycreeper birds, for example, all offer particularly dramatic examples of the processes of speciation and subsequent adaptation. Last month, biologists added another organism to that list. The ancestor of Hawaiian stick spiders (genus Ariamnes), which have elongated and sometimes sail-shaped abdomens, arrived on Kauai about 1.7 million years ago and proceeded to diversify and evolve in a remarkably predictable manner.
Read more »Scoring big pharma’s match with superbugs
So-called superbugs, germs resistant to one or more of the medications meant to kill them, represent a new villain in the global fight for human health and welfare. Many of the “wonder” drugs discovered in the 1950s, which once seemed to promise the end of infectious disease, are no longer effective against many microbes. For example, Staphylococcus aureus, a common source of skin infections, used to be easily treated with penicillin, but today many strains are resistant to that and several other antibiotics, making a minor scratch potentially life-threatening. Drug-resistant bacteria, viruses, fungi, and parasites cause more than 700,000 deaths per year worldwide. In many cases, contracting a resistant strain of a pathogen more than doubles one’s chance of dying of the infection. Pharmaceutical companies are pivotal in combatting this global health emergency — and last month the Access to Medicine Foundation announced a new way to track drug companies’ efforts in this fight. Consumers, policymakers, and other drug companies can consult the Antimicrobial Resistance Benchmark to find out what companies are doing (and which are doing the most) to ensure that antimicrobials remain a useful part of our medical arsenal. But how exactly does a drug company fight superbugs?
Read more »A warmer world leads to female-biased sea turtle populations
Beach development, hunting, pollution, and fishing all threaten the survival of the endangered green sea turtle. Now, new research has uncovered a more unusual risk they face: lack of males. At some beaches in Australia, more than 99% of new hatchlings are now female. Older cohorts of turtles are also female-biased, though less severely, suggesting that the feminization of this population has been going on for decades. Since it’s the female sea turtles that invest heavily in producing eggs and one male can mate with many females, a dip in the male segment of the population doesn’t mean immediate doom, but what happens if the species skews so far female that there aren’t enough would-be dads to go around? Scientists are concerned about how these all-girl generations of turtles will affect the long term prospects for the species. Why is this occurring, and what can be done to nudge the turtles back towards gender parity?
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