You can call it “crawfish,” “crawdad,” “mudbug,” “mudpuppy,” or even “yabbie.” But we like the nickname “crusty.” That’s short for crustacean, a kind of creature that has a skeleton on the outside of its body and two pairs of antennae. “Crusty” reminds us that the crayfish, like every plant and animal, has its very own place in the immense variety of the world’s creatures.

One of the things we’re meant to do in this world is to discover just how orderly God is. We do that by studying what He made. To study something is to try to make sense of it.

A big part of making sense of things is to sort them out. Taxonomy is the sorting and naming of all living things. People give animals a variety of common names, like “mudbug.” But to avoid confusion, scientists agree to use just one Latin name for each living thing. The critter invading Germany’s waterways is the species Procambarus clarkii. “Species” is the last and most specific level in the chart of living creatures.

The chart we use today is based on a system that was first organized in the 1700s by the Swedish scientist Carolus Linnaeus. He used characteristics of living things to put them into categories. He started with the largest, most general description—Kingdom. He finished with the narrowest, most specific description, Species.