In deuterostomes, which means "mouth second," the blastopore becomes the anus, and the mouth forms later. In protostomes, which is Greek for "mouth first," the mouth arises from the blastopore. The plesiomorphic condition, found in the Protostomes, is for the blastopore to become the mouth. In lower animals the embryo is nourished by the yolk. This blastopore-to-anus developmental pathway is found in Chordata, Hemichordata, Echinodermata (starfish, sea urchins, sea cucumbers, etc.), uniting these groups into a monophyletic group called the Deuterostomes. The appearance of the blastopore locates the caudal region of the future embryo and. In most mammals the blastula attaches itself to the uterine lining, thus stimulating the formation of a placenta, which will transfer nutrients from the mother to the growing embryo. through the overlying ectoderm are indicated by the cross hatched area. What structure is derived from the blastopore? Animals in which the blastopore becomes the mouth are called protostomes those in which the mouth develops after the anus are called deuterostomes (from the Greek "deutero," meaning second, and "stoma," meaning mouth).
What is it called when the blastopore becomes the mouth? The posterior end of the primitive streak in Birds is notoriously variable, and nobody has made a systematic. Now, we have got the complete detailed explanation and answer for everyone, who is interested!
This is a question our experts keep getting from time to time. The involuted cells of notochord and mesoderm migrate and diverge from the blastopore and primitive streak to their future positions within the developing.
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