Adapted from “Phylum Lab” produced by the National Aquarium in Baltimore
The diversity of animal life on Earth is astounding. Each animal has a unique body plan which allows it to survive and adapt to its given surroundings. With such an abundance of species, classifying animals into different categories is necessary. At first the diversity of animals can be overwhelming, but after further research and observation, many likenesses appear. These similarities become the basis for taxonomists, the biologists who specialize in classifying animals, to organize and bring order to the animal kingdom.
Animals are classified into categories called taxa and are sorted according to their phylogeny (evolutionary history), body plan and similarity of characteristics. There are seven principle levels that organisms can be placed into: Kingdom, Phylum, Class, Order, Family, Genus, Species. All animals are in the Kingdom Animalia. As you move from species to kingdom, the animals that are grouped together share fewer and fewer characteristics at each succeeding level.
The next level after Kingdom is Phyla, which is the main focus of the lab today. Even though there are approximately thirty-five phyla within the animal kingdom, 98 percent of all animals are classified into eight of them. To get even more specific, seven of the eight phyla are invertebrates. Invertebrates comprise most of the animal kingdom, with almost 75 percent of all animals on earth being insects. They out number humans by a million to one!
From Phylum, animals are then broken down into more specific categories: class, order, family, genus, species. For example, a shark, a bird, and a human are all in the Phylum Chordata. So, what similarities do these animals have? Taxonomists would agree that all these animals have similar internal skeletons. However, these animals would not be grouped in the same Class. This process would continue until the animal is classified all the way to