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  • Drawing a bead on ancient symbolic behavior

    Anatomically modern humans evolved in Africa nearly 200,000 years ago, but researchers have long debated why there seems to be a gap between when hominins started looking modern and when they began acting modern. Some of the most important indications of modernity, such as cave art and certain types of advanced tools, don’t show up in the… Read More
  • Microbes within microbes within microbes

    We are, fundamentally, a fusion. As I wrote in my essay for Science on the origin of eukaryotes, there’s now a wealth of evidence that our cells evolved from the combination of two different microbes. The mitochondria that generate fuel for our cells started out as free-living bacteria. Today, they still retain traces of their origin in t… Read More
  • The origins of handedness

    About 85% of humans worldwide are right-handed, at least for most tasks they perform. Most of the rest are left-handed; true ambidexterity is very rare. Yet researchers are not sure just when in hominin evolution a tendency to use one hand over the other evolved—evidence for handedness in other animals is inconsistent and controversial—nor why… Read More
  • Excitable plants

    In researching last month’s Origins essay on the origin of the nervous system, I was struck by the range of behavior and electrical excitability exhibited by organisms that lack nerve or muscle cells. Some sponges, for example, have a sneeze-like reflex that flushes out sediment (see a video), whereas others generate electrical “ac… Read More
  • On the Origin of Genomes

    We live in genome-centric times. Already high-throughput sequencing machines have unraveled genetic blueprints for thousands of organisms, as well as viruses and organelles, and cheaper, faster technology promises thousands more in the near future. But where did the first genomes come from—and how? What rules govern how they function and what the… Read More
  • Did early plants seed animal diversity?

    Animals owe their survival to plants and other photosynthetic organisms. But according to a study published last week in Nature, photosynthesizers gave early animals another big assist, unleashing the Cambrian explosion, the big bang of animal evolution, 540 million years ago. The paper asserts that late in the Precambrian—the time before the C… Read More
  • On the Origin of Sleep

    From an evolutionary perspective, sleep might seem like a dangerous waste of time. When animals slumber, they’re less responsive to their surroundings and potentially more vulnerable to predators. And of course it’s hard to reproduce when you’re fast asleep. Many researchers assume that sleep must offer some adaptive advantage tha… Read More
  • On the Origin of Eukaryotes

    Toadstools, people, plants, and amoebae have strikingly similar cells. All these organisms keep their DNA coiled up in a nucleus. Their genes are interspersed with chunks of DNA that cells have to edit out to make proteins. Those proteins are shuttled through a maze of membranes before they can float out into the cell. And… Read More
  • A laughable academic debate

    But what about gorillas? That’s what some may be wondering after they stop chuckling at The Daily Show‘s in-depth analysis of the academic battle over whether chimpanzees or orangutans are human’s closest relative. Read More