ZoologyLesson 7 of 7 in the course Invertebrates

Deuterostomes: Development, Echinoderm Diversity, and Chordate Traits

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

This lesson introduces the developmental features that distinguish deuterostomes from protostomes and surveys the major deuterostome clades. These patterns help explain how embryonic development is connected to animal relationships.

The name Deuterostomia comes from Greek roots meaning “mouth second.” During development, the first opening of the primitive gut, the blastopore, generally becomes the anus. The mouth forms later, on the opposite side of the embryo. By contrast, in protostomes (“mouth first”), the blastopore typically becomes the mouth and the second opening becomes the anus.

All flashcards

Archenteron
The primitive gut tube formed during gastrulation that develops into the alimentary canal.
Enterocoelom
A coelom formed when outgrowths of the archenteron separate and expand.
Ambulacraria
The deuterostome clade containing Echinodermata and Hemichordata.
Ossicles
Small calcareous plates that form part of the echinoderm endoskeleton.
Madreporite
An aboral opening through which seawater enters a sea star's water vascular system.

Quiz questions

  1. In typical deuterostome development, what does the blastopore become?Answer: The anus
  2. What is one consequence of regulative cleavage in early deuterostome embryos?Answer: Separated early cells may still develop into a normal embryo
  3. Which system uses canals and tube feet to support sea star movement and feeding?Answer: The water vascular system
  4. How can a sea star begin digesting prey inside a partly opened bivalve?Answer: It everts its cardiac stomach through its mouth
  5. Which feature do hemichordates share with chordates?Answer: Pharyngeal slits

Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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