Astonishing Aquatic Life

There are so-called multi-cellular organisms, metazoan, which strictly speaking only consist of a mass of cells. They only occur in water. The cells are connected tissue-like with each other, resulting in different body shapes. Sponges belong to these organisms, for example.

Usually you only know them from the bathroom, and many people don’t realise that they actually use a dead organism for scrubbing their bodies. We are talking about sponges. The sponges you can buy in a supermarket today are made of synthetic materials, of course, but in former times sponges from the sea were used. Today 'natural sponges' are still available in special shops.

Sponges neither have inner organs nor sense organs. They reproduce sexually by means of germ cells, which are situated somewhere on the 'body'. A sponge is also able to bud and develop growing buds, so whole sponge colonies may form.

Like Creatures from Another Planet

Another well-known representative, which also 'only' consists of many cells, but no organs, is the jellyfish. These creatures, which have already been mistaken for bathing caps, can in fact be very poisonous. They occur in many shapes and sizes and often with beautiful colour patterns. Their body wall consists of two layers of cells with a supportive layer in between. The tissues are already specialised for a certain task in the body. They form a stomach by simply closing their cap like a bag.

There are also worms without any organs that only consist of a strand of cells. The biggest species title belongs to thread- and roundworms. In Latin it is called Placentonema gigantissima. It lives in sperm whales and may grow to a length of 8 m!