Protostome
Frederic P. Miller, Agnes F. Vandome, John McBrewster
High Quality Content by WIKIPEDIA articles! Protostomia are a clade of animals. Together with the deuterostomes and a few smaller phyla, they make up the Bilateria, mostly comprising animals with bilateral symmetry and three germ layers. The major distinctions between deuterostomes and protostomes are found in embryonic development. In animals at least as complex as earthworms, the embryo forms a dent on one side, the blastopore, which deepens to become the archenteron, the first phase in the growth of the gut. In deuterostomes, the original dent becomes the anus while the gut eventually tunnels through to make another opening, which forms the mouth. The protostomes were so named because it used to be thought that in their embryos the...
ISBN: 978-6-1308-1643-8
Издательство:
Книга по требованию
Дата выхода: июль 2011
