Porifera

Porifera is a phylum of simple aquatic animals commonly known as sponges. They are multicellular organisms that lack true tissues and organs. Instead, their bodies are made up of specialized cells that perform various functions.

Body Structure: Sponges have a porous body with numerous small openings called ostia through which water enters. The water is then filtered through a system of canals and chambers before being expelled through a larger opening called the osculum.
Cell Types: Porifera have several types of cells, including choanocytes (collar cells) that help in capturing food particles, and amoeboid cells that aid in digestion and nutrient distribution.
Skeleton: Many sponges have a skeleton made of spicules, which are tiny, needle-like structures composed of calcium carbonate or silica. These spicules provide structural support to the sponge's body.
Reproduction: Sponges can reproduce both sexually and asexually. Asexual reproduction occurs through the formation of buds or by fragmentation, while sexual reproduction involves the release of sperm and eggs into the water.
Habitat: Porifera are primarily marine organisms, although some species can be found in freshwater environments. They are often attached to a substrate such as rocks or coral reefs.

When studying Porifera, it's important to focus on the following key points:

Understand the unique body structure of sponges, including the function of ostia and osculum in water circulation.
Learn about the different cell types present in Porifera and their respective functions in the sponge's body.
Explore the diversity of skeletal structures in sponges and their role in providing support and protection.
Examine the methods of reproduction in Porifera and the advantages of each method in different environmental conditions.
Consider the ecological significance of sponges and their interactions with other organisms in their habitat.