Why Do Crabs Vs Porifera

The crab of Phylum Anthropoda is much more advanced and complex than the sponges of Phylum Porifera. One of the main differences that makes crabs more advanced is the fact that crabs have a body cavity which allows them to have different organ systems, this is called coelmate. A sponge does not posess a body cavity, which is called acolemate, but they do posess a Gastrovascular cavity. A Gastrovascular cavity has only one opening, the mouth/anus. Being a coelomate is more advanced because it allows for the development of complex organ systems, like digestive, circulatory, respiratory systems. Organ systems such allows animals to have specialized organs, which help do a certain job with the most efficiency. Having a Gastrovascular cavuty might
not be as efficient as it only has one opening. This might not be the bast as food and waste might get mixed up. Another difference that makes crabs more advanced is the fact the Anthropods have jointed appendages, meanwhile sponges do not. Meanwhile sponges are sessile creatures, which means that they can not move. Jointed appendage allows Anthropods to mkae powerful movements, and aid in locomotion. All Anthropods are known for their exoskeleton which is a hard shell around it. Having an exoskeleton allows the crab a source of protection, which are useful when defending against a preditor or attacking prey. Sponges do not have an exoskeleton, although is forms many symbiotic relationships (relationships that help two species), it would be easier to ‘hurt’ a sponge because of

the lack of protection than a crab.
Phylum Anthropods also have more complex body systems than Phylum Porifera. Anthropods have an open circulatory system, complete digestive system, and a nervous system which includes a brain, and a ventral nerve cord. Having all these organ systems makes Anthropods more complex as they have more specialized organs which complete all the required tasks with great efficiency. Unlike sponges crabs are motile all their lives. This means that carbs have the ability and adantage of locomotion. This is important to have because as a result of being motile crabs can be both male and female (Dioecious). Being diecious, means that crabs reproduce sexually, which as a result creates more genetic diversity. Sponges can reproduce sexually as well but because they are sessile (unable to move) for its adult life it is harder to do this. In order for them to reproduce sexually to get genetic diversity they have to be hemaphroditic (have both male and female gamates). Sponges send their gamates through the water and hope that it lands on another sponges coller cell. Many gamates do not land on collar cells and as a result they do not become sponges. It is much easier and faster for crabs to reproduce rather than
sponges.