Science Puzzle
What’s Hiding in a Drop of Pond Water?
Scoop a single drop of water from a pond and hold it up to the light. It looks like nothing at all, perhaps a little cloudy.
Now put that same drop under a microscope. How many living things do you think you would find inside it?
The Answer
A crowded, violent, thriving world. A single drop of pond water can hold thousands of living things and often millions of bacteria, and every one of them is hunting, eating, dividing or being eaten.
You will find amoebae oozing along on flowing arms and swallowing their prey whole. Paramecia rowing past on thousands of beating hairs. Green algal cells quietly making sugar out of sunlight, the base of the whole food web. Rotifers spinning water into their mouths with a crown of moving hairs. Predators, grazers, and plants, all inside a drop you could barely feel on your fingertip.
When Antonie van Leeuwenhoek first saw these creatures in the 1670s through his hand-made lenses, he called them animalcules and almost nobody believed him. He had discovered that the world is full of life we had never even suspected. Most of the living things on Earth are still too small to see.
The principle: Microorganisms. Most life on Earth is microscopic, and a complete ecosystem of producers, grazers and predators can exist within a single drop of water.