I wrote this article on brine shrimp for my Diversity of Life curriculum. It covers the interesting aspects, is easy to read, has pictures, and only takes up one page. I’ve also included some things to look for when examining them under a microscope.
Here is the full text (see the Word version to print):
Brine shrimp are small animals that live in saltwater. They are found in oceans as well as the Great Salt Lake in Utah, where they serve as food for many other creatures. Brine shrimp (also known incorrectly as “sea monkeys”) eat mostly bacteria and algae. This gives them an important place in the Great Salt Lake food web, because the algae in the water can grow out of control if there is nothing to eat it. Many people keep them as pets because they are easy to feed and maintain, and they are a good source of protein for aquarium fish.
Brine shrimp reproduce (have babies) very quickly. They have several ways to reproduce that help them survive harsh and changing conditions. They lay eggs which have protective coatings called cysts, and these cysts are tough enough to survive a winter of being dried out and frozen. In the spring, baby brine shrimp will hatch from the cysts. Interestingly enough, some brine shrimp don’t wait for the winter to come – they hatch before the eggs they are in are even laid! If you look at brine shrimp under a microscope, you can sometimes see this happening. Even more amazing is the fact that the females can clone themselves by laying unfertilized eggs if there are no males around. All of these ways to reproduce make brine shrimp good survivors in harsh, changing environments.
It’s a good thing brine shrimp are good at reproducing quickly, because they don’t have many defenses against getting eaten. Birds that stop in Great Salt Lake while they are migrating eat them by the millions, and fish eat them too. The only defense they have is that they can survive in water that’s too salty for fish and other creatures.
The brine shrimp is an amazingly complex creature for something smaller than a fingernail clipping!
As you examine the brine shrimp under the microscope, look for:
* Feelers/swimming appendages/arms
* Eggs inside (black dots) and hatching
* How they eat
* Mating behavior
* 8 characteristics of living thing – how many can you observe?