
All chordates possess the following features except
A. Dorsal hollow nerve cord
B. Pharyngeal gill slits
C. Notochord
D. Amnion
Answer
497.4k+ views
1 likes
Hint:- A chordate is an animal belonging to the phylum Chordata. Chordates are among the most developed phylum and are bilaterally symmetric and consist of a coelom, metameric segmentation, and closed circulatory system, digestive and excretory system.
Complete answer:
The characteristic features include the presence of a notochord, a dorsal hollow nerve cord, paired pharyngeal gill slits, a post-anal tail, and the presence of an endostyle or thyroid gland. The notochord is a rod-like structure. The notochord lies along the anteroposterior axis of the body and is derived from the mesodermal cells. The functions of the notochord are it serves as a midline tissue that provides directional signals to surrounding tissue during development and as a site of muscle attachment, and vertebral precursor.
Pharyngeal slits are filter-feeding organs found in Invertebrate and some chordates (lancelets and tunicates) and hemichordates which live in the aquatic environment. The dorsal hollow nerve cord is formed from a part of the ectoderm that rolls, forming the hollow tube. In vertebrates, the dorsal nerve cord is further developed into the central nervous system, which consists of the brain and spinal cord. It is one embryonic feature unique to all chordates, among the other four chordate features.
Amnion is one of the four extraembryonic membranes or foetal membranes i.e amnion, chorion, allantois, and yolk sac. The space between the amniotic membrane and embryo is filled with amniotic fluid which helps in the prevention of the desiccation of the embryo by providing the embryo with a water-retaining environment and proper nutrition.
Thus, the right option is D.
Note:- Phylum Chordata consists of three subphylums as follows -
● Urochordata
● Cephalochordata
● Vertebrata
Amnion is present only in mammals, birds, and reptiles of vertebrae. It is the innermost layer that encloses the embryo. It is not present in all the chordates like Urochordates and Cephalochordates.
Complete answer:
The characteristic features include the presence of a notochord, a dorsal hollow nerve cord, paired pharyngeal gill slits, a post-anal tail, and the presence of an endostyle or thyroid gland. The notochord is a rod-like structure. The notochord lies along the anteroposterior axis of the body and is derived from the mesodermal cells. The functions of the notochord are it serves as a midline tissue that provides directional signals to surrounding tissue during development and as a site of muscle attachment, and vertebral precursor.
Pharyngeal slits are filter-feeding organs found in Invertebrate and some chordates (lancelets and tunicates) and hemichordates which live in the aquatic environment. The dorsal hollow nerve cord is formed from a part of the ectoderm that rolls, forming the hollow tube. In vertebrates, the dorsal nerve cord is further developed into the central nervous system, which consists of the brain and spinal cord. It is one embryonic feature unique to all chordates, among the other four chordate features.
Amnion is one of the four extraembryonic membranes or foetal membranes i.e amnion, chorion, allantois, and yolk sac. The space between the amniotic membrane and embryo is filled with amniotic fluid which helps in the prevention of the desiccation of the embryo by providing the embryo with a water-retaining environment and proper nutrition.
Thus, the right option is D.
Note:- Phylum Chordata consists of three subphylums as follows -
● Urochordata
● Cephalochordata
● Vertebrata
Amnion is present only in mammals, birds, and reptiles of vertebrae. It is the innermost layer that encloses the embryo. It is not present in all the chordates like Urochordates and Cephalochordates.
Latest Vedantu courses for you
Grade 11 Science PCM | CBSE | SCHOOL | English
CBSE (2025-26)
School Full course for CBSE students
₹41,848 per year
Recently Updated Pages
Master Class 12 Economics: Engaging Questions & Answers for Success

Master Class 12 Maths: Engaging Questions & Answers for Success

Master Class 12 Biology: Engaging Questions & Answers for Success

Master Class 12 Physics: Engaging Questions & Answers for Success

Master Class 12 Business Studies: Engaging Questions & Answers for Success

Master Class 12 English: Engaging Questions & Answers for Success

Trending doubts
What is the Full Form of PVC, PET, HDPE, LDPE, PP and PS ?

What are saprophytes Give two examples class 12 biology CBSE

How do you convert from joules to electron volts class 12 physics CBSE

Mirage is a phenomena due to A Refraction of light class 12 physics CBSE

Why did French artist Frederic sorrieu prepare a series class 12 social science CBSE

What is Nutrition Explain Diff Type of Nutrition ?
