Physiological Processes in Sponges
Porifera are simple organisms yet have systems to regulate their different physiological processes through a variety of mechanisms. These mechanisms regulate metabolism, reproduction, and locomotion. But Porifera are intrinsically simple, for instance they do not have immune or nervous systems.
Metabolism
Porifera have very simple systems. They trap food as water passes through their body. Water enters through the body pores (ostia) and exits out through the osculum. Water diffuses through the body, and this process supports most functions in the organism. Tiny bacteria, some smaller than 0.5 microns in size, get filtered out by nutrition cells, which are then ingested by phagocytosis. Food particles must be smaller than the cells.
Excretion and circulation are also carried out by the diffusion between the water passing through those Porifera and the cell. Diffusion provides all the oxygen and also releases the carbon dioxide. Waste is excreted into the flowing water by individual cells.
Reproduction
Sponges reproduce using both sexual and asexual methods. Asexual reproduction happens most commonly by fragmentation, in which pieces break off the sponge and develop into new individuals, or by budding, wherein a section grows and detaches from parent.
Sponges are hermaphroditic, meaning one individual can produce both gametes (eggs and sperm). Sexual production occurs in different ways for different species. Some produce gametes year round while others are temperature dependent.
Ejection of spermatozoa may be a timed and coordinated event, and is carried by the water to find other Porifera. After internal fertilization, the larvae is realised to become a sponge.
Locomotion
Sponges are generally sessile as adults and spend their lives attached to a fixed substratum. They do not show movement over large distances as do free-swimming marine invertebrates. However, sponge cells are capable of creeping along substrata via organizational plasticity. Under experimental conditions, researchers have shown that sponge cells spread on a physical support, demonstrating a leading edge for directed movement. It has been speculated that this localized creeping movement may help sponges adjust to micro-environments near the point of attachment. It must be noted, however, that this pattern of movement has been documented in laboratories, but it remains to be observed in natural sponge habitats.
Porifera are simple organisms yet have systems to regulate their different physiological processes through a variety of mechanisms. These mechanisms regulate metabolism, reproduction, and locomotion. But Porifera are intrinsically simple, for instance they do not have immune or nervous systems.
Metabolism
Porifera have very simple systems. They trap food as water passes through their body. Water enters through the body pores (ostia) and exits out through the osculum. Water diffuses through the body, and this process supports most functions in the organism. Tiny bacteria, some smaller than 0.5 microns in size, get filtered out by nutrition cells, which are then ingested by phagocytosis. Food particles must be smaller than the cells.
Excretion and circulation are also carried out by the diffusion between the water passing through those Porifera and the cell. Diffusion provides all the oxygen and also releases the carbon dioxide. Waste is excreted into the flowing water by individual cells.
Reproduction
Sponges reproduce using both sexual and asexual methods. Asexual reproduction happens most commonly by fragmentation, in which pieces break off the sponge and develop into new individuals, or by budding, wherein a section grows and detaches from parent.
Sponges are hermaphroditic, meaning one individual can produce both gametes (eggs and sperm). Sexual production occurs in different ways for different species. Some produce gametes year round while others are temperature dependent.
Ejection of spermatozoa may be a timed and coordinated event, and is carried by the water to find other Porifera. After internal fertilization, the larvae is realised to become a sponge.
Locomotion
Sponges are generally sessile as adults and spend their lives attached to a fixed substratum. They do not show movement over large distances as do free-swimming marine invertebrates. However, sponge cells are capable of creeping along substrata via organizational plasticity. Under experimental conditions, researchers have shown that sponge cells spread on a physical support, demonstrating a leading edge for directed movement. It has been speculated that this localized creeping movement may help sponges adjust to micro-environments near the point of attachment. It must be noted, however, that this pattern of movement has been documented in laboratories, but it remains to be observed in natural sponge habitats.