Porifera Phylum

Porifera Phylum

As time progresses, animals have become bigger and display more of a complex body. In some cases, this is not always true. The Poriferas and Cnidarians do not have a difficult structure like the Platyhelminthes. The body structures can determine a lot about how these animals survive in their environment, and it is important that their structure can manage their distribution of gases, and obtain food and waste. These facts and information will show proof of the many characteristics and bodily functions that these three animals display.

I found it interesting that the most recognized organisms in the Porifera Phylum are called sponges. In fact, Porifera is the oldest phylum in the kingdom of Animalia, and have been around for the last six hundred million years. Some important characteristics that can be identified with Porifera are: they have no definite symmetry, no organs, no nervous system, mostly have a skeleton of spicules, all filter feeders, multicellular organisms, and they live in aquatic environments. Sponges are a unique and simplistic animal, and have been around for a long time. These sponges can be found in rivers and streams or in the depths of the ocean. Sponges can show a great variety of forms, but their basic organization is quite simple. Sponges are a water filtering system. They have a convenient canal system that helps them receive food and pump water through a canal, which water comes in through pores called ostia. After, it flows through a chamber called spongocoel. It exits through the oscula, which are large openings. Sponges consist of three layers: an outer layer of pinacocytes, an inner and non-living layer with amoebocytes that assist reproduction and bring food particles from the choanocytes to other non-feeding cells, and an inner layer of flagellated collar cells called choanocytes. The choanocytes bring in food and remove waste products. Since Poriferas do not have organs, or a complex structure they can not move, so this canal system is an easier way for the sponge to get what it needs. Since their bodies are simple, the form only consists of a single tube only two layers thick. The advantages to having less of a structure are the sponges only need a little to survive, unlike most animals.

Another animal with less of a structure are the Cnidarians, which are considered true animals. In fact, these exceptional animals have true tissues, develop from embryonic gastrula, and it acquires multicellular reproductive structures, which is what makes them different from sponges. Cnidarians have only three classes: Hydrozoa, Scyphozoa, and Anthozoa. It is easy to remember Cnidarians are recognizable as jellies and anemones, and most common are jellyfish. The embryonic endoderm and ectoderm are what make up the two distinct body layers of Cnidarians. Since Cnidarians are organisms with two tissue layers making Cnidarians diploblastic. Their body structure has a mouth, which traps prey into the gastrovascular cavity. It uses its tentacles to trap the prey. Water is pumped through the gastrovascular cavity as well. Most of the Cnidarians are radially symmetrical. Unlike stinging the human skin, the tentacles can immobilize their prey. There are two basic shapes that are identified with the cnidarians animal, which are the polypoid or medusoid. Polyploids are the shape of corals and anemones. Medusoids are different than the polyploids, and are jellyfish. Cnidarians have an advantage over other animals. The tentacles on their body structure make it easier to grab their prey. Their tentacles can even sting humans, but it is not fatal at all,