Classification of Animals Test - 1

Invertebrates are animals that neither possess nor develop a vertebral column (commonly known as a backbone or spine), derived from the notochord.

Presence of pores is the characteristic feature of poriferans.

Poriferans are commonly called sponges. Poriferans do not have mouths, instead they have tiny pores in their outer walls through which water is drawn.

Molluscs are invertebrates of a large phylum which includes snails, slugs, mussels, and octopuses. They have a soft unsegmented body and live in aquatic or damp habitats, and most kinds have an external calcareous shell.

Starfish, sea urchin and antedon belong to the phylum Echinodermata. Hydra belongs to the phylum Cnidaria.

The flatworms, flat worms, Platyhelminthes, Plathelminthes, or Platyhelminths are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates.

Wuchereria bancrofti is a human parasitic roundworm that is the major cause of lymphatic filariasis, which is elephantiasis.

Earthworms are known as farmer`s friend because they consume animal and plant wastes and release organic matter as their excreta. This excreta of earthworms increases soil fertility and improves water holding capacity of the soil.