What was the purpose of the fate of the blastopore? The reference is to the flattened nature of the animals in this phylum. Platyhelminthes (pla-te-hel-MIN-thes) is made of two Greek roots that mean “flat worms”. They have a central nervous system containing a brain and a nerve cord. Which symmetry do Platyhelminthes have?įlatworms’ bodies are bilaterally symmetrical and they have a defined head and tail region. Thus, nematodes are sometimes referred to as pseudocoelomates (Fig. They have no circulatory system or body cavity (coelom), but they do have an excretory and digestive system.Īlthough nematodes do have a space in the body between the digestive tract and the body wall, it is not lined with tissue and is not considered to be a true coelom. Does platyhelminthes have a coelom?įlatworms are bilaterally symmetrical with a defined head and tail region and a centralized nervous system containing a brain and nerve cords. Porifera (no blasts) and Cnidaria (diploblast). In most phyla, the blastopore becomes the mouth animals with this type of development are called protostomes, meaning “first (or primary) mouth”. What is the fate of blastopore in porifera? A modern consensus phylogenetic tree for the protostomes is shown below….Protostomia. molluscs, annelids, platyhelminths, and rotifers). ![]() arthropods, nematodes) and the Spiralia (e.g. Protostomes are divided into the Ecdysozoa (e.g. Instead, the blastopore closes during development, and a new opening becomes the mouth. The blastopore becomes neither the mouth nor the anus. What is the blastopore fate in platyhelminthes?
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