Porifera means pore-bearing. Sponges are covered with tiny pores on the outside called ostia (2). Ostia lead to an internal system of canals which leads to one or more larger holes called oscula, which are the openings to the out side. Ostia are surrounded by donut shaped cells called porocytes. The chambers within the canals are lined up with cells called choanocytes, or collar cells. The collar cells consist a sticky funnel shaped collar and a hair-like whip called a flagellum. The collar cells beat their flagella back and forth to force the water through the sponge. The water brings in nutrients and oxygen and takes out the carbon dioxide. The two purposes of providing food and removing wastes are served due to this function. The sticky collars also pick up tiny particles of food and bacteria brought in by the water (2).
Unlike the cells of most other animals, the cells of sponges do not form into various organs like kidney, liver, or nerves. Sponge cells are totipotent (Dawkins 2004). The totipotent cells could give rise to reproductive cells or other types of cells of the organism. In theory, this enables a sponge to live forever (Dawkins 2004).
Sponges can produce sexually as well as asexually. Most sponges are hermaphroditic, which means each adult can act as either female or male. Asexual reproduction happens by budding and fragmentation (4). With this type of reproduction pieces or fragments of the sponge's body are broken off the by the water currents, and they are carried by the currents to a different location. There they attach themselves to the ocean floor and grow to be an adult sponge. Some of the sponges form internal buds, called gemmules. These can survive even extremely unfavorable conditions. They survive even after the rest of the sponge dies due to the unfavorable conditions (4).
Unlike the cells of most other animals, the cells of sponges do not form into various organs like kidney, liver, or nerves. Sponge cells are totipotent (Dawkins 2004). The totipotent cells could give rise to reproductive cells or other types of cells of the organism. In theory, this enables a sponge to live forever (Dawkins 2004).
Sponges can produce sexually as well as asexually. Most sponges are hermaphroditic, which means each adult can act as either female or male. Asexual reproduction happens by budding and fragmentation (4). With this type of reproduction pieces or fragments of the sponge's body are broken off the by the water currents, and they are carried by the currents to a different location. There they attach themselves to the ocean floor and grow to be an adult sponge. Some of the sponges form internal buds, called gemmules. These can survive even extremely unfavorable conditions. They survive even after the rest of the sponge dies due to the unfavorable conditions (4).
The word sponge, for most of us relates to the scrubbing sponge or a bath sponge. It is easy to forget that there is much more to sponges than the scrubbing and bath. The sponges are living animals that live in the water. They are stuck to the floor in the oceans, sea, and rivers. They are known as Porifera. The Poriferans are simple multi cellular animals. There are about 5000 to 10,000 of species of Porifera that are known today. Out of them only 150 species live in fresh water. The rest of the sponges dwell in salt-water. Sponges are very primitive creatures that evolved around 500 million years ago (1). There are many different types of sponges all over the world. Some of these sponges are very colorful and beautiful (1).
Sponges are multi-cellular. They are known be diploblast, which means having two layers of cells (Dawkins 2004). As an adult they may have multiple cell layers, but initially they all arise from the two layers that were present in the early embryo (Dawkins 2004). Most are sponges are asymmetrical, though some of them exhibit radial symmetry (Dawkins 2004). The typical body form of a sponge consists of a hollow pitcher surrounded by lots of small holes and opens up on the top with a big hole. Sponges do not have a coelom. A coelom is the cavity within the body in which the intestines, lungs, heart, kidney, etc., are located, and it is sealed off from the outside world. The body cavity of sponges is large, it is open to the outside world, and it enables the sponge to consume food (Dawkins 2004). Sponges do not have any internal organs or a nervous system. Their skeleton is made of tiny, needle-like splinters, or a mesh of protein called spongin (2) Most of the Demospongiae are made of spongin. Some of the sponges are made of both spicules and spongin. Bath sponges are made of calcereous or siliceous spicules, and they are therefore soft to the touch. Most of the bath sponges are Demospongiae .
Sponges gain their structure from a skeleton of collagen with reinforcing spicules of either calcium or silicon compounds. They are either radially symmetrical or asymmetrical. These structures are full of pores in which specialized collar cells sit, constantly drawing in water and filtering out food particles. The waste water is then pushed into a central chamber and out a large opening.
Sponges are extremely slow-moving or sessile filter-feeders that draw water through pores and specialized filter cells to gather food. Sponges are the most primitive type of animal in existence, featuring a cell-based organization where different cells have different tasks, but do not form tissues. All sponges live in the water, with a large majority of species living in the oceans.
Sponges gain their structure from a skeleton of collagen with reinforcing spicules of either calcium or silicon compounds. They are either radially symmetrical or asymmetrical. These structures are full of pores in which specialized collar cells sit, constantly drawing in water and filtering out food particles. The waste water is then pushed into a central chamber and out a large opening.
Sponges are extremely slow-moving or sessile filter-feeders that draw water through pores and specialized filter cells to gather food. Sponges are the most primitive type of animal in existence, featuring a cell-based organization where different cells have different tasks, but do not form tissues. All sponges live in the water, with a large majority of species living in the oceans.