what is parazoa and eumetazoa
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Answer:
Parazoa Versus Eumetazoa
The first dichotomous branching point of the phylogenetic tree of Kingdom Animalia (Fig. 6) separates organisms that do not have true tissues from those with true tissues. A tissue is an aggregation of cells that performs a function. Parazoans lack true tissues, whereas eumetazoans have true tissues. There has been some debate about whether parazoans, the sponges, should even be considered animals; however, molecular data clearly place them at the based of the animal tree. Eumetazoans have distinct collections of cells that are arranged for specific purposes. Thus, the presence of true tissues is the first bifurcation in the animal phylogeny.
Figure 6. Overview of Animal Diversity and Body Plans.(Click image to enlarge)
Sometimes it can be easier to see similarities between groups at the larval stage. For example, sponge larva are free-swimming with flagellated cells (Fig. 7). As adults, they settle in one place and are no longer mobile; they do retain flagella on their cells (we will discuss the structure of sponges in more detail in Tutorial 19).
Answer:
Eumetazoa are animals whose tissue are organized into true tissues and there is a development of organs. Parazoa lack this tissue organization. This signifiies that eumetazoa have more complexly organized tissue than parazoa do. Examples of parazoa belong to phylum porifera, or sponges.