Characteristics of Poriferans
Poriferans, also called sponges, are aquatic organisms (the majority of them are marine organisms) that either have no symmetry or have radial symmetry. Their bodies, which have a tube shape, a cup shape, or an irregular shape, have multiple pores that are interlinked by thin channels. These channels lead to a central cavity, called the atrium, which is linked to the outside by an opening called the osculum. Inside the channels, there are cells known as choanocytes, which are specialized in capturing food.
Poriferans stay upright due to a skeleton made of small spines called spicules. They feed by filtration. Water, which contains food particles, enters through the pores and exits through the osculum with the food remaining trapped inside. They live attached to the sea floor, rocks, or other living beings. They normally reproduce asexually, most commonly by fragmentation or by budding. They are also able to reproduce sexually; most sponges are hermaphroditic, although some are unisexual.