Bilaterally symmetrical animals with three germ layers and no coelom are referred to as acoelomates. Examples of such animals include flatworms (phylum Platyhelminthes), which possess a simple body plan with a solid tissue structure and lack a body cavity. These organisms exhibit bilateral symmetry and develop from three germ layers: ectoderm, mesoderm, and endoderm. Acoelomates typically have a more primitive organizational level compared to coelomate animals.
Coelomate refers to animals that possess a true coelom, which is a fluid-filled body cavity completely lined by mesoderm. This body cavity allows for greater flexibility and mobility in these animals compared to acoelomates or pseudocoelomates. Examples of coelomate animals include most vertebrates and some invertebrates like annelids and arthropods.
Three cell layers known as the ectoderm, mesoderm, and endoderm. They are also referred to as the primary germ layers, because all of the organs and tissues of the embryo will be formed from them.
The three embryonic tissue layers of animals are ectoderm, mesoderm, and endoderm. These layers give rise to different specialized tissues and organs in the developing organism during the process of gastrulation. Ectoderm develops into structures like the skin and nervous system, mesoderm gives rise to muscles and bones, and endoderm forms the lining of the gut and associated organs.
Acoelomates have several disadvantages. They do not have any protective covering for their organs, no place for diffusion, and several other things. Psuedocoelomates have a fake coelom, or a coelom that was lost during evolution or mutation.
Characteristics. All coelenterates are aquatic, mostly marine. The bodyform is radially symmetrical, diploblastic and does not have a coelom. The body has a single opening, the hypostome, surrounded by sensory tentacles equipped with either nematocysts or colloblasts to capture mostly planktonic prey.
Cephalopods, like other members of the phylum Mollusca, develop from three primary germ layers: ectoderm, mesoderm, and endoderm. These layers give rise to various tissues and organs during embryonic development, with the ectoderm forming the outer body covering, the mesoderm developing into muscles and the circulatory system, and the endoderm forming the digestive tract. This triploblastic organization is characteristic of bilaterally symmetrical animals.
The space between the two layers of the mesoderm is called the coelom. It is a body cavity that forms during embryonic development and gives rise to various organs, such as the heart, lungs, and digestive system.
Platyhelminthes, commonly known as flatworms, exhibit a simple body plan characterized by a flattened, bilaterally symmetrical shape. They lack a true coelom, have a soft body, and possess three tissue layers: ectoderm, mesoderm, and endoderm. Their bodies often feature a distinct head region with sensory organs and a gastrovascular cavity for digestion, which serves both nutrient absorption and waste removal. Platyhelminthes typically exhibit a lack of a specialized respiratory and circulatory system, relying on diffusion for gas exchange.
Cockroaches do have a true coelom, because their bodies are made up of the three layers of cells. It is called a haemocoel because the body of the body cavity is filled with blood.
The phylum Cnidaria is comprised of animals that are radially symmetrical and have a jellylike material, called mesoglea, between two layers of cells.
Coelomate refers to animals that possess a true coelom, which is a fluid-filled body cavity completely lined by mesoderm. This body cavity allows for greater flexibility and mobility in these animals compared to acoelomates or pseudocoelomates. Examples of coelomate animals include most vertebrates and some invertebrates like annelids and arthropods.
Composite
triploblastic organisms :1-Acoleomates: with no cavity, and three cell layers.2-coleomates : with cavity, and surrounding with ( mesoderms )3-pseudocoleomates : with cavity filled with fluid, and lined with ( mesoderms )
That is not accurate. Cnidarians actually have a simple coelom called a gastrovascular cavity, which functions in digestion and circulation. Sponges, on the other hand, lack a true coelom and instead have a porous body filled with channels for water circulation.
Composite
stratovolcano, or composite volcano
Animals with a body cavity lined with tissue from the mesoderm are known as coelomates. This type of body plan is found in more complex animals such as annelids, mollusks, arthropods, echinoderms, and chordates. Having a coelom allows for more complex organ systems and better body movement.