A cluster of 3.4 billion-year-old fossilized cells
What’s the News: Geologists have found fossils of microorganisms from 3.4 billion years ago, which may be the oldest fossils ever uncovered. Since these microbes date from a time when Earth’s atmosphere was still oxygen-free, astrobiologists could look for similarly structured microbes when searching for extraterrestrial life.
What’s the News: Around 600 million years ago, Earth’s first multicellular moving animals evolved. Known as the Ediacaran fauna, these early slug- and worm-like creatures fed off microbial mats that covered the ocean floor. For years, scientists have debated how these animals kept themselves from suffocating because the ocean at the time is thought to have had less than half of its current oxygen levels. Looking at modern environments that are also oxygen-depleted, scientists have discovered that oxygen levels spike near biomats, plant-like bacteria that pump out oxygen as a waste product of photosynthesis. “We think that animals used the small but highly oxygenated zones as oases,” lead author Murray Gingras told Nature, giving the world’s first complex animals the kick-start they needed to evolve. “This is a really neat solution to an old problem,” Ediacaran researcher Jim Gehling told New Scientist. Read More