Microscopic Life In A Drop Of Water

When we think about single-celled life, we often picture tiny amoeba-like transparent circular organisms. But life in the micro-world isn't as simple as that. Single-celled organisms vary greatly in both shape, size, color and function. So in this video we are taking a closer look at the incredible microscopic diversity in a few drops of water from a single forest pond sample. These two large bluish cells are called stentors, and they are some of the biggest single-celled organisms on the planet. They move and feed using tiny beating hair-like projections called cilia. The cilia create a flow of water and food particles towards the front of the cell where it can be ingested. Inside each cell we can clearly see the different ingested materials, where it is currently being digested. Stentors are also known as trumpet anemocules, due to their trumpet shape when stretched. In the sample I also found a lot of different green single-celled organisms, of different shapes and sizes. These two look like they are dancing. One thing they have in common is the presence of algae living inside the cells, giving them their green color. This benefits both the algae as well as the cells. The algae feed on waste products produced inside the organisms, and in return the algae produce oxygen for the cells and work a bit like internal oxygen factories. This symbiotic relationship allows the cells to live in oxygen-poor habitats. These yellow organisms are not worms, but single-celled organisms as well. The cells are called spirostom, and despite their appearance they are actually some of the fastest organisms in the world. Spirostom cells contain muscle-like fibers, allowing them to contract rapidly when startled. This contraction happens in just a few milliseconds, which is one of the fastest known movements on earth. Here a stentor has been trapped in a sea of spirostom. So far we have only looked at unicellular life, but there were of course also multicellular organisms in the sample. This one is a rotifer, one of the smallest animals on the planet. However even though it's an animal, it is no larger than the single-celled organisms we have looked at. As you can see, rotifers also use cilia for movement and feeding. Inside the animal we can clearly see a set of jaws chewing on the ingested food particles. So the next time you walk by a pond, you now know a bit more about the incredible microscopic diversity that hides beneath the surface. If you have any ideas on what you want to see under the microscope next, please leave a comment below. Thank you for watching.