What do plants do during solar eclipse?
As some scientists used the Great American Eclipse in August 2017 to watch how bees and birds dealt with sudden midday darkness, researchers in Wyoming investigated big sagebrush. Tracking its reactions at the leaf level, scientists saw it experience a slowdown in activity as darkness fell, followed by shock at the sun's surprise return.
Daniel Beverly, a doctoral student in botany and hydrology at the University of Wyoming and the paper's lead author, and his colleagues measured photosynthetic rate, as well as the speed of transpiration — how quickly its leaves lose water. During the 2 minutes and 18 seconds of complete darkness, photosynthesis and transpiration rates fell.
Over the course of the eclipse day, the team estimated, the average big sagebrush managed about 14% less photosynthesis than it would have if the sun hadn't been blocked. If a plant is drought-stressed, an eclipse might be bad news, like "losing 14% of a day's income when you're already broke," Beverly said.
Crocodiles had a vegetarian phase
Imagine you're a small mammal of the Mesozoic. Snuffling around one day, you run into a cat-size, scaly, big-eyed reptile that looks not unlike a crocodile found in the 21st century. Spotting you, he opens his mouth wide to reveal … tiny, intricate teeth. Then he turns and munches on some leaves.
Research published in Current Biology suggests that vegetarianism evolved at least three separate times in ancient crocs — a conclusion reached after scientists studied the teeth sported by many species, including the Simosuchus described above.
About 250 million years ago, scores of crocodyliform species could be found across the globe, some on land and some in seas and rivers. A particular species might eat only plants, only animals, or both.
Keegan Melstrom, a geobiology graduate student at the University of Utah, and his co-author, Randall Irmis, analyzed 146 teeth from 16 extinct crocodyliform species. They used a method called orientation patch count rotated. From a scan of an object, the method generates a numerical score indicating the complexity of the object's shape. "It allows us to compare teeth that have no landmarks in common," Melstrom said.
This proved useful for studying prehistoric crocs, he said, whose teeth often have "no modern-day analogues."
Half of the ancient species seemed to have been on the plant-eating end of the spectrum — "a genuine surprise," Melstrom said.