Chapter 29, Problem 1VCQ

Figure 29.3 Which of the following statements about common features of chordates is true?

1. The dorsal hollow nerve cord is part of the chordate central nervous system.

In vertebrate fishes, the pharyngeal slits become the gills.

Humans are not chordates because humans do not have a tail.

Vertebrates do not have a notochord at any point in their development; instead, they have a vertebral column.

Summary Introduction

Introduction:

The key characteristic features of the phylum Chordata are a notochord, a dorsal hollow nerve cord, pharyngeal slits, a post-anal tail and endostyle/thyroid gland.

Answer to Problem 1VCQ

Correct answer:

The correct answer is option (a). The dorsal hollow nerve cord is part of the chordate central nervous system.

Explanation of Solution

Explanation for the correct answer:

In chordate, a dorsal hollow nerve cord is present dorsal to the notochord in embryos during embryonic development. The dorsal nerve cord gets developed into the spinal cord and the brain of which give rise to the Central Nervous System. Thus, option (a) is the correct answer.

Explanation for the incorrect answer:

Option (b) is given: Invertebrate fishes, the pharyngeal slits become the gills. In fishes, the pharyngeal slits do not become the gills. Thus, it is an incorrect answer.

Option (c) is given: Humans are not chordates because humans do not have a tail. Humans are chordates and have a tail in the embryonic stage. Thus, it is an incorrect answer.

Option (d) is given: Vertebrates do not have a notochord at any point in their development; instead, they have a vertebral column. Vertebrates have a notochord at any point in their development. Thus, it is an incorrect answer.

Conclusion

All the chordates have pharyngeal slits, dorsal hollow nerve cord, post-anal tail and notochord at some or other sage of their life.