Deuterostome

Definition

A deuterostome is a type of animal characterized by its embryonic development, where the first opening that forms during gastrulation becomes the anus, and the mouth develops later. This group includes major phyla such as chordates and echinoderms, highlighting unique developmental pathways that distinguish them from other animals like protostomes, where the mouth forms first.

5 Must Know Facts For Your Next Test

1. Deuterostomes are divided into two main groups: echinoderms, such as starfish and sea urchins, and chordates, which include all vertebrates.
2. The term 'deuterostome' is derived from Greek, meaning 'second mouth', reflecting their unique embryonic development pattern.
3. In deuterostomes, the coelom (body cavity) forms through enterocoely, where pouches of mesodermal tissue pinch off from the archenteron during development.
4. Some well-known examples of deuterostomes include humans, birds, reptiles, and fish, showcasing the diversity of life forms that share this developmental trait.
5. Deuterostomes exhibit radial cleavage during early embryonic division, which is different from the spiral cleavage seen in protostomes.

Review Questions

• How does the embryonic development of deuterostomes differ from that of protostomes?
  • Deuterostomes differ from protostomes primarily in their embryonic development. In deuterostomes, the first opening formed during gastrulation becomes the anus, while the mouth develops later. In contrast, protostomes have their mouth develop first from the initial opening. This fundamental difference in developmental patterns highlights their distinct evolutionary pathways.
• Discuss the significance of enterocoely in deuterostome development and how it affects body plan formation.
  • Enterocoely is significant in deuterostome development as it describes how the coelom forms through pouches that bud off from the archenteron. This method of coelom formation allows for a more complex body plan that contributes to the overall structural organization in deuterostomes. It provides space for organ development and allows for greater specialization in various systems within these animals.
• Evaluate the evolutionary implications of the unique developmental features found in deuterostomes compared to other animal groups.
  • The unique developmental features of deuterostomes have profound evolutionary implications as they reflect adaptations that have led to diverse body plans and complex organisms. Their mode of embryonic development has been linked to significant evolutionary innovations seen in chordates, including advanced nervous systems and specialized organ systems. Analyzing these features helps understand the evolutionary relationships between deuterostomes and other animal groups, revealing how these traits may have influenced survival and diversification throughout evolutionary history.

Related terms

Protostome:

A group of animals where the first embryonic opening becomes the mouth, leading to different developmental patterns compared to deuterostomes.

Gastrulation:

The process during embryonic development where the blastula reorganizes into a multilayered structure, establishing the foundation for body plans in animals.

Chordate: An animal belonging to the phylum Chordata, which includes all vertebrates and some invertebrates, characterized by having a notochord at some stage of development.