ZoologyLesson 1 of 2 in the course Vertebrates

Chordate Characteristics, Invertebrate Groups, and Vertebrate Evolution

5 flashcards · 5 quiz questions · 5 match pairs · 4 fill-in sentences · English

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Summary

Chordates share a distinctive set of features that appear at some point during their development. In this lesson, you will learn what these features are and how they function.

All animals in phylum Chordata possess five characteristics during at least one stage of life. In some chordates, several features occur only in the embryo or larva.

These features are shared across chordates, but their appearance and function can change greatly in different groups.

All flashcards

What is the notochord?
A flexible, rod-shaped mesodermal structure between the digestive tube and nerve cord that provides axial support and muscle attachment.
What becomes of the dorsal hollow nerve cord in vertebrates?
It develops into the brain and spinal cord, which together make up the central nervous system.
What does the endostyle do?
It produces mucus that traps food particles, and cilia move the food toward the gut. It is homologous to the vertebrate thyroid gland.
What are pharyngeal slits?
Openings connecting the pharynx to the outside. They can help with water flow and filter feeding, and have been modified into other structures in vertebrates.
What is the post-anal tail, and what can it do?
It is a body extension beyond the anus containing muscles and skeletal elements. It can aid swimming, balance, courtship, or signaling.

Quiz questions

  1. Which set lists the five chordate characteristics present at some stage of development?Answer: Notochord, dorsal hollow nerve cord, pharyngeal slits or arches, post-anal tail, endostyle or thyroid gland.
  2. Which statement describes adult lancelets?Answer: They retain all five chordate characteristics as adults.
  3. What happens to a tunicate larva during metamorphosis?Answer: It loses the notochord, nerve cord, and tail, while pharyngeal slits and the endostyle remain.
  4. Which four extraembryonic membranes support development in amniotes?Answer: Yolk sac, amnion, chorion, and allantois.
  5. What feature defines gnathostomes?Answer: They are vertebrates with jaws.

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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