Where does the mass of a multi-ton oak come from? Not the soil, which supplies only water and a few minerals. Most of its dry matter comes from carbon dioxide in the air: through photosynthesis, the tree captures carbon to build sugars, cellulose and wood. In the 1600s, Van Helmont measured the puzzle: his willow gained 74 kg while the soil lost just 57 grams.
In 2022, a young tagged bar-tailed godwit flew from Alaska to Tasmania in about 11 days of nonstop flight, covering 13,560 km without eating, drinking or landing. Before departure, these birds pile on huge fat reserves and shrink their digestive organs, which are useless during the journey.
To escape rivals, a dung beetle rolls its ball of dung in a straight line. At night, it holds its course using the glowing band of the Milky Way. In a planetarium, researchers showed that beetles rolled straight under a starry sky but wandered aimlessly when the galaxy was switched off. It was the first animal known to navigate this way.