characterstics featurea of notochord with long explaination with details
Answers
Answer:
Animals in the phylum Chordata share four key features: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.
Learning Objectives
Identify the key features of the chordates
Key Points
These characteristics are only present during embryonic development in some chordates.
The notochord provides skeletal support, gives the phylum its name, and develops into the vertebral column in vertebrates.
The dorsal hollow nerve cord develops into the central nervous system: the brain and spine.
Pharyngeal slits are openings in the pharynx that develop into gill arches in bony fish and into the jaw and inner ear in terrestrial animals.
The post-anal tail is a skeletal extension of the posterior end of the body, being absent in humans and apes, although present during embryonic development.
Key Terms
notochord: a flexible rodlike structure that forms the main support of the body in the lowest chordates; a primitive spine
nerve cord: a dorsal tubular cord of nervous tissue above the notochord of a chordate
pharyngeal slit: filter-feeding organs found in non-vertebrate chordates (lancelets and tunicates) and hemichordates living in aquatic environments
Characteristics of Chordata
Animals in the phylum Chordata share four key features that appear at some stage during their development (often, only during embryogenesis) (:
image
Figure 29.1A.129.1A.1 : Defining characteristics of chordates: In chordates, four common features appear at some point during development: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.
a notochord
a dorsal hollow nerve cord
pharyngeal slits
post-anal tail
Notochord
The chordates are named for the notochord: a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and also in the adult stage of some chordate species. It is located between the digestive tube and the nerve cord, providing skeletal support through the length of the body. In some chordates, the notochord acts as the primary axial support of the body throughout the animal’s lifetime.