New: In addition to Science Today, now Science Tonight. An easy-to-digest scientific minute to brush your teeth. This time the answer to the question: Why do all seeds have a different size? And this time I’m talking about plants.
The largest grain – weighing tens of kilograms and about half a meter in length – is the double coconut. This one comes from a very rare palm. One grows on only two islands, with only thousands left. The smallest seed comes from a tropical orchid. They are one millionth of a gram. It has a length of 0.05 mm. But why the huge differences?
It’s not just about the size of the parents, it’s about what the seeds have to withstand. They receive exactly the amount of energy and protection that the fetuses they are carrying need to survive. Sometimes, for example in the case of a double coconut, this means that the seed “you” has to survive after being floating in the sea for several months. Orchid seeds may be small, but they leave in the millions. Because their chances of finding the perfect place on the branch to grow are slim.
If a plant or tree grows in a place with a lot of shade, the seeds will be larger again, like an oak tree. Because young plants have to get up in the air quickly to get enough light. Oftentimes, big isn’t necessarily better. For example, animals eat large seeds faster.
Thanks to: BBC Science Focus: Why do seed sizes vary?