The Porifera phylum consists of animals known as sponges. These organisms are aquatic animals and there are approximately 5,000 known species of sponges. Sponges come in an array of shapes, colours, and sizes. These organisms can form different shapes such as tubes, fans, cups, cones, blobs, barrels, and crusts. They are microcellular organisms, with the absence of cell walls, tissues, organs, and body symmetry. Sponges can be either radially symmetrical or asymmetrical. These organisms ecological role is to filter out bacteria and contamination from the water.
MOVEMENT: Sponges are sessile organisms, meaning that they are fixed in one spot, and do not move. Sponges are attached to solid rocks, thus making them immobile.
BODY COVERINGS: Their bodies are full of pores, allowing water to easily circulate through them. Sponges have two outer cell layers that are divided by a gel like layer known as the mesoglea or mesohyl. The mesoglea is acellular meaning that they have no cells. Sponges have a cellular level of organization, which means different cells carry out various functions, but similar cells are not organized into tissues and bodies are a type of collection of different types of cells. In order for these organisms to protect themselves, they must use their sharp spicules on their preadators.
SUPPORT: Sponges are one of the many organisms that are invertabrates. Sponges body shapes are maintained by either spicules, which are sharp, pointed, needle like structures made up of calcium carbonate, or spongin fibers, which is a flexible, skeletal material that is made from protein. Both spicules and spongin fibers are located inside of the mesohyl.
NUTRITION: Sponges obtain their food by waiting for the water currents to bring their food close enough to their pores so that it can flow into their bodies, and then collected into specialized cells. The water enters the sponge when the water is removed from it. This is a process known as filter feeding. Some common things that are apart of a sponges’ diet includes detritus particles, plankton, and bacteria.
RESPIRATION: Due to the fact that sponges do not have a respiratory system, sea sponges get their oxygen from the flow of water. Since gas exchange between sponges is so straightforward, there is no particular place where the exchange happens. The water enters small pores, and then circulates and disperses through the sponge’s body with the help of cells known as choanocytes. These cells have flagella, which move the water in the sponge.
CIRCULATION: Sponges lack a circulatory system, so instead, water currents push the water into the sponges and the flagella moves the water around within the sponge.
EXCRETION: The water current assists sponges to remove their metabolic waste.
RESPONSE: Since sponges do not have a nervous system, nor do they possess the five senses, it is commonly wondered how these organisms react. Due to these circumstances, there is no way for sponges to respond or react, but instead they must rely on their spicules to help fight against predators.
REPRODUCTION: Sponges reproduce both asexually and sexually. Sponges reproduce asexually during a process where new sponges grow out of an adult sponge. This process is known as budding. Sponges can also reproduce aexually when a piece of an adult sponge detaches, which then develops into an organism. This process is known as fragmentation. These organisms also have the ability to reproduce sexually. Most sponges have both eggs and sperm, making them hermaphrodites. Although sexual reproduction can be done with just the one organism, it is more commonly done between two sponges. First, the sperm cell is released into the water, which then swims to fertilize the eggs. Fertilization will occur either on the inside or outside of the sponge’s body depending on the species. After the eggs are fertilized, they develop into larvae, or parenchymula, The larvae or parenchymula then look for a surface in open water where they can develop into an adult sponge.