GENERAL HISTOLOGY

OESOPHAGUS STOMACH

ECHINODERMS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which of the following patterns of development is characteristic of echinoderms and lancelets?
A
Acoelomate
B
Pseudocoelomate
C
Protostome
D
Deuterostome
Explanation: 

Detailed explanation-1: -Echinoderm Antimicrobial Peptides In the deuterostomes, the blastopore can differentiate into the anus, while the mouth can develop from another embryonic area. The echinoderms and the chordates are deuterostomes, while all other invertebrates are protostomes.

Detailed explanation-2: -Formation of mouth and anus The defining characteristic of the deuterostome is the fact that the blastopore (the opening at the bottom of the forming gastrula) becomes the anus, whereas in protostomes the blastopore becomes the mouth.

Detailed explanation-3: -Echinoderms are deuterostome marine organisms. This phylum of animals bear a calcareous endoskeleton composed of ossicles covered by a spiny skin. Echinoderms possess a water-based circulatory system. The madreporite is the point of entry and exit for water for the water vascular system.

Detailed explanation-4: -During development the mouth of deuterostomes develops from an opening into the embryonic gut other than the blastopore, which develops into the anus. The coelom (a fluid-filled body cavity lined with mesoderm) develops from buds off the embryonic gut. A number of deuterostomes have distinctive larval forms.

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