Sponges Phylum: Porifera Order: Spongillidae The sponge body is supported by tiny needles. These spicules help people to identify the different types of sponges.	Did you know that a natural sponge is a type of soft-bodied animal, not a plant! Sponges are often overlooked, as most of them are not brightly coloured, and have a stone-like appearance. They are usually brown, yellow or grey, but can sometimes be green.
	Habitat	Freshwater sponges can be found in unpolluted, nutrient-rich ponds, lakes and canals. When they grow in rivers, they grow on stones in the shape of a thin bread crust, which is an adaptation to prevent them from being swept away by the water. When they grow in ponds and still waters, they can grow into more blob-like shapes. Many species live in salt water.
	Moving around	The sponge larvae swim through the water, propelled along by tiny moving hairs.
	Feeding	They eat: particles of food in the water. Sponges filter small food particles out from the water. They absorb water through pores (tiny holes). The water travels through tiny tunnels and micro-organisms are filtered out by tiny hairs (known as cilia - sounds like "sillier"). The sponge then gets energy from feeding on these micro-organisms. Clean water is then ejected.
	Reproduction	In the summer or autumn, special globular structures called "gemmules" are produced asexually (by a single parent without sexual fertilisation). The "gemmules" are very resistant to harsh conditions, and survive the winter. They hatch into young sponges the following spring. Sponges also reproduce sexually, resulting in microscopic larvae which swim, by the use of cilia, to settle and grow into new sponges.
	Breathing	Cilia draw water in through pores. As water passes through a network of tunnels inside the sponge, oxygen is absorbed.
	Size	Sponges vary enormously in size.
	Fun Fact	Although sponges are made out of animal cells, some of them house microscopic algae which produce energy from the sun. The algae give the sponge a green or orange colour. Only sponges which live near a good source of light can support algae.