What phylum do segmented worms belong to?

Segmented worms, including earthworms and leeches, belong to the phylum Annelida. This classification is based on the key characteristics of members of this phylum, such as their segmented body structure, which is divided into multiple segments or metameres. Each segment contains its own set of organs and systems, contributing to an enhanced level of complexity and organization.

Annelids also exhibit a coelom, a body cavity that is lined with mesoderm, allowing for more efficient movement and organ development. The segmentation in Annelida is fundamental for their locomotion, as it allows independent movement of each segment, enhancing their ability to adapt to various environments.

In contrast, the other phyla listed do not share these characteristics. Arthropoda encompasses invertebrates with jointed limbs and an exoskeleton, Nematoda refers to roundworms that are unsegmented and typically have a distinct body shape, and Chordata includes animals that possess a notochord at some stage in their development, which is not a feature of segmented worms. Understanding these distinctions is essential for accurately classifying and comprehending the biological diversity within the animal kingdom.