Sponges are a diverse group of sometimes common types, with about 5000 species known across the world. Sponges are primarily marine, but around 150 species live in fresh water. Sponges have cellular-level organization, meaning that that their cells are specialized so that different cells perform different functions, but similar cells are not organized into tissues and bodies are a sort of loose aggregation of different kinds of cells. This is the simplest kind of cellular organization found among parazoans.

sponges include a system of pores (also called ostia) and canals, through which water passes. Water movement is driven by the beating of flagellae, which are located on specialized cells called choanocytes (collar cells). Sponges are either radially symmetrical or asymmetrical. They are supported by a skeleton made up of the protein collagen and spicules Reproduction by sponges is by both sexual and asexual means.

Asconoid Example:: Leucosolenia Sponges have three different types of body plans Asconoid sponges are shaped like a simple tube perforated by pores. The open internal part of the tube is called the spongocoel; it contains the collar cells. There is a single opening to the outside, the osculum. Example:: Leucosolenia Classification Phylum : Porifera Class : Calcarea Order : Homocoela Genus : Leucosolenia

Syconoid Phylum: Porifera Class : Calcarea Order : Heterocoe sponges tend to be larger than asconoids and have a tubular body with a single osculum. The synconoid body wall is thicker and the pores that penetrate it are longer, forming a system of simple canals. These canals are lined by collar cells, the flagellae of which move water from the outside, into the spongocoel and out the osculum. Example:: Sycon Classification Phylum: Porifera Class : Calcarea Order : Heterocoe Genus : Sycon

Leuconoid These are the largest and most complex sponges. These sponges are made up of masses of tissue penetrated by numerous canals. Canals lead to numerous small chambers lined with flagellated cells. Water moves through the canals, into these chambers, and out via a central canal and osculum.

Example:: Euspongia Classification Phylum :Porifera Class : Demosongia Order : Keratosa Genus : Euspongia Euspongia is the common bath sponge. It is a deep sea form and is found in the Mediterranean Sea. It is like a cup and the skeleton is made of sponging fibres only (siliceous spiculels are absent). It is used during bath to clean body

Hydra look very much like miniature sea anemones. Classification: Phylum: Coelentrata Class : Hydrozoa Order : Diploblastica Genus : Hydra Hydra look very much like miniature sea anemones. They can be white brown or green. Hydra have a saclike body and a circle of tentacles at around the body opening.

This opening is used for both taking in food and eliminating wastes. Hydra don't have eyes but they can sense light They will also reproduce easily, either asexually, by forming buds or by laying a single egg. Hydra are carnivorus and will eat anything they can manage to catch including single celled animals, small crustaceans, worms, insects, and other tiny animals

Fasciola

Fasciola life cycle

Fasciola eggs

Fasciola intermediate host Lymnaea sp.

Cercaria of Fasciola

The infective stage of Fasciola Encysted metacercaria

Fasciola