Holozoa

Holozoa is a superphylum of animals that includes all animals with true tissues, including sponges, cnidarians, and bilaterians. The term was coined by biologists to encompass the entire animal kingdom, excluding the sponges, which are considered a separate phylum. Holozoa is characterized by the presence of true tissues, which are groups of cells that work together to perform specific functions. This is in contrast to sponges, which lack true tissues and are instead composed of individual cells. The superphylum Holozoa is further divided into several major groups, including the Cnidaria, Ctenophora, Platyhelminthes, Nematoda, Annelida, Mollusca, Arthropoda, Echinodermata, and Chordata. These groups are characterized by a variety of body plans and modes of locomotion, and they have evolved a wide range of adaptations to their environments. The study of Holozoa is an important area of research in biology, as it provides insights into the evolution of animal diversity and the mechanisms underlying the development of complex tissues and organs.