Why classify different types of invertebrates?

Invertebrates make up the largest group of animals on earth. They’re an incredibly diverse group, ranging from scorpions to octopuses to centipedes. Despite their vast diversity, some of their smallest members are the most interesting.

Animal owners often learn the hard way how difficult it can be to keep their pets flea-free and happy. One of the biggest concerns pet owners run into is the fact that outdoor treatments, while effective in killing fleas are also toxic to their pets or harmful to the plant life in their backyards. One solution to this problem is Steinerma carpocapsae, a type of nematode. S. carpocapsae is a natural predator of fleas. Applying a spray populated with S. carpocapsae in the outdoor areas your pet spends time in can have dramatic effects, without putting your animal at risk.^[1]

Figure 1. Ancylostoma caninum, a type of hookworm, attached to the intestinal mucosa.

However, not all invertebrates are so beneficial. In fact, not even all nematodes are benign: hookworms, pinworms, and whipworms are all parasites that can infect a human host. Hookworms make their way into the small intestine and feed off of human blood. While infections are typically asymptomatic, a serious infection can result in anemia and cause complications in pregnancy. Pinworms use humans to distribute their eggs, and can cause itching and insomnia in their hosts. Whipworms also use their hosts to distribute eggs, and while small infections are asymptomatic, a person infected with many worms may experience abdominal pain, tiredness, and diarrhea.