non chordata

Phylum Aschelminthes: Definition, Characteristics, Classification and Examples

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Definition,Characteristics, Classification and Examples of Phylum Aschelminthes

Phylum Aschelminthes (Gr., askes = cavity ; helmins = worm) is a group of bilaterally symmetrical, unsegmented, and pseudocoelomate animals. They are typically characterized by a cylindrical or thread-like body covered with a tough, flexible cuticle. The phylum includes organisms that are predominantly aquatic or parasitic in nature, such as nematodes (roundworms).

Phylum Porifera: Definition, Characteristics, Classification and Examples

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Phylum Porifera: Definition, Characteristics, Classification and Examples

Phylum Porifera is a group of simple, multicellular, aquatic animals commonly known as sponges. They are characterized by their porous body structure, which allows water to circulate through specialized channels, enabling them to filter-feed by extracting nutrients and oxygen from the water. Most sponges are marine, though some are found in freshwater. Porifera are among the most ancient animal groups, with a simple organization that makes them pivotal to understanding the evolution of multicellular organisms.