Prehistoric Insects and Birds

EXTRA LEARNING: Since one of today's presentations was about arthropods, I thought I'd share this recent article published in National Geographic (originally based on a paper in the Proceedings of the National Academy of Sciences). Previously, scientists had linked insect size to fluctuations in oxygen levels in the atmosphere of prehistoric Earth. Recall how insects respire. Higher oxygen levels would thus allow them to evolve larger bodies. Recent studies by researchers at UC Santa Cruz, however, propose a different story. According to them, insect size decreased due to predation from birds which were showing up on the evolutionary scene. Small insects were more maneuverable than large insects, thus conferring small insects an advantage. These researchers note that after the appearance of birds, even during periods of higher oxygen levels, insect size remained small. Interesting. Read more about it if you like: "Giant Bugs Eaten Out of Existence by First Birds?"

Also interesting: carnivorous caterpillars on Hawaii. Similar video clip.