Major Phyla Phylum: Protozoa and Porifera

Phylum : Protozoa

This phylum includes a great diversity of small, microscopic organ-isms. These are single celled eukaryotes. Protozoa are one-celled animals found worldwide in most habitats. Most species are free living, but all higher animals are infected with one or more species of protozoa. Their locomotion happens using pseudopodia, cilia or flagella.


The nutrition is either autotrophic or heterotrophic. They reproduce either asexually or by sexual methods. Ex : Amoeba, Paramoecium, Plasmodium.

Phylum : Porifera

These are multicellular, aquatic organisms. They have a cellular grade of construction without the occurrence of tissues. The sponges belonging to this phylum are characterised by the presence of a canal system in their body. Poriferans are commonly referred to as sponges.

The body wall contains spicules. Sponges are characterized by the possession of a feeding system unique among animals. They can reproduce both by asexual and sexual methods. Example: Sponges


Fig: Sponges