Question

8. What makes the kingdom Animal Animalia and no longer a metazoan or eumetazoan? What distinguishes them from plants and fungi?

Answer 1

Kingdom Animalia is composed of all animals. The animal kingdom is the largest kingdom among the five kingdoms. Animals are multicellular eukaryotes. Its main features are-

• Bilaterally symmetrical and triploblastic.
• Less segmented body.
• Well-developed organ and organ system.
• Open circulatory system.
• Limbs are present.

Metazoans have an adult body composed of numerous cells differentiated into tissues and organs and usually a digestive cavity lined with specialized cells, and that usually include the coelenterates and all higher animals but sometimes also include the sponges. The main difference between Metazoa and Eumetazoa is that Metazoa is a group of multicellular animals excluding Porifera (sponges) whereas Eumetazoa is a group of multicellular animals excluding Porifera and Placozoa.

As we see little more advanced characters that extend beyond metazoa and eumetazoa are collectively referred to as animal in group Animalia.

As multicellular organisms, animals differ from plants and fungi because their cells don't have cell walls; their cells may be embedded in an extracellular matrix (such as bone, skin, or connective tissue); and their cells have unique structures for intercellular communication (such as gap junctions).