Did you know that helicopters grew on trees long before people invented them?
These seed pods make beautiful little helicopters. With three blades they spin quickly as they fall. A breeze can lift them up and carry them along. We would drop them from the highest window, or have races to see whose would land first.
If you live in North America or Europe you might have seen or played with a different type of helicopter seed – from a maple tree (in Europe it’s called sycamore tree).
These two types of plant aren’t related but they’ve both come up with the same solution to a problem.
If trees drop their seeds on the ground below, the tall older trees block the energy-giving sunlight from the short young trees. And it gets a bit crowded. If the seeds are planted somewhere else the young trees will have more space, sunlight, and other things they need. They have a better chance of surviving and in turn making their own seeds.
Both of these have trees solved this problem by making helicopter seedpods that fly their seeds away.
Some clever people have worked out the science behind how the maple seed spins. http://www.livescience.com/3672-secret-flight-helicopter-seeds.html
Hiptage benghalensis: Creative Commons license by Siddarth Jude Machado. Creative Commons license. From http://indiabiodiversity.org/observation/show/378471?species%3DHiptage%20benghalensis%20(L.)%20Kurz
Sugar maple: Creative Commons license. Acer Saccharum Marsh – Steve Hurst @ USDA-NRCS PLANTS Database. https://commons.wikimedia.org/wiki/File:Acer_saccharum_seeds.jpg