Question

How do members of the Bilateria clade differ from other animals?

How are the Porifera (Parazoa) distinguished from the Eumetazoa?

What are the distinguishing features of the Ctenophora?

What are the components of a circulatory system?

How does a closed circulatory system differ from an open circulatory system?  

How is oxygenation, nutrient distribution, and waste removal accomplished in animals that lack a circulatory system?

Because of the end of the semester approaching rapidly, instructors are burning through the material fast, and I'm having a hard time keeping up.

I really appreciate the help! Thank you in advance.

Answer 1

1). The members of Bilateria clade show bilateral symmetry. This group includes most of the animals except sponges, comb jellys, and cnidarians. The animals with bilateral symmetry have anterior, posterior, dorsal, and ventral body regions.

2). Parazoa includes the Phylum Porifera. In contrast to the Eumetazoa, the tussues of Proifera are poorly defined and they do not contain true organs. They (sponges) do not have a circulatory system, digestive system, or nervous system. Whereas the organs of Eumetazoa are well defined (including the circulatory system)