Children often wonder about the differences between various creatures, such as spiders, worms, and centipedes. In response to these queries, Wizzie Brown, a program specialist with the Texas A&M AgriLife Extension Service, provides valuable insights into the classification and characteristics of these organisms.
One frequently asked question is whether spiders are classified as insects. The answer is no; spiders belong to a different category within the arthropods. While both spiders and insects share the characteristic of having an exoskeleton, they are classified into separate subphyla. Spiders fall under the subphylum Chelicerata, as opposed to insects, which belong to the subphylum Hexapoda.
An important distinction lies in their body structures. Spiders possess two main body regions: the prosoma and the opisthosoma. They also have specialized mouthparts known as chelicerae, which include fangs capable of injecting venom. In contrast, insects are characterized by three body regions—head, thorax, and abdomen—along with a pair of antennae and three pairs of legs. This fundamental difference in anatomy sets spiders apart from insects, despite their shared classification as arthropods.
Understanding Worms and Centipedes
The conversation also extends to worms, which can cause confusion due to certain insects being named after them. For instance, terms like silkworms and inchworms refer to immature stages of moths or beetles, rather than true worms. True worms are classified into three categories: segmented worms, flatworms, and roundworms.
Segmented worms, such as earthworms, have distinct body segments and may possess structures called parapodia that assist in movement. Flatworms, which include tapeworms and planarians, have soft, unsegmented bodies and breathe through their skin. Roundworms, on the other hand, are tubular and possess openings at both ends for food intake and waste expulsion.
As for centipedes, they are also not classified as insects, although they are more closely related to insects than to worms. Both centipedes and insects share the characteristic of being arthropods with exoskeletons. Centipedes belong to the group Myriapoda and possess a long, worm-like body with numerous legs, distinguishing them from insects’ structured body regions.
Brown’s expertise sheds light on these classifications, helping to educate young inquisitors about the biodiversity of the insect world. For those with additional questions about bugs and other related topics, Brown encourages inquiries, ensuring that curiosity continues to drive learning.
This informative discussion not only clarifies common misconceptions but also emphasizes the importance of understanding the intricate relationships between different species in the animal kingdom.
