
All chordates possess the following features except
A. Dorsal hollow nerve cord
B. Pharyngeal gill slits
C. Notochord
D. Amnion
Answer
491.7k+ views
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.
Recently Updated Pages
Earth rotates from West to east ATrue BFalse class 6 social science CBSE

The easternmost longitude of India is A 97circ 25E class 6 social science CBSE

Write the given sentence in the passive voice Ann cant class 6 CBSE

Convert 1 foot into meters A030 meter B03048 meter-class-6-maths-CBSE

What is the LCM of 30 and 40 class 6 maths CBSE

What is history A The science that tries to understand class 6 social science CBSE

Trending doubts
Father of Indian ecology is a Prof R Misra b GS Puri class 12 biology CBSE

Who is considered as the Father of Ecology in India class 12 biology CBSE

Enzymes with heme as prosthetic group are a Catalase class 12 biology CBSE

A deep narrow valley with steep sides formed as a result class 12 biology CBSE

An example of ex situ conservation is a Sacred grove class 12 biology CBSE

Why is insulin not administered orally to a diabetic class 12 biology CBSE
