All vertebrates are chordates but all chordates are not vertebrates, why ?

Question

Match the following genes of the lac operon listed in column ‘A’ with their respective products listed in column ‘B’: \begin{center} \begin{tabular}{|c|c|} \hline Column A (Gene) & Column B (Product)
\hline a. ‘i’ gene & (i) \(\beta\)-galactosidase
b. ‘z’ gene & (ii) Lac permease
c. ‘a’ gene & (iii) Repressor
d. ‘y’ gene & (iv) Transacetylase
\hline \end{tabular} \end{center} Select the correct option:

Answer 1

To understand why "All vertebrates are chordates but all chordates are not vertebrates," let's explore the characteristics and differences between chordates and vertebrates:

Definition and Characteristics of Chordates:
- Chordates form a large phylum of animals that exhibit certain characteristics at some stage of their development. These characteristics include a notochord, a dorsal hollow nerve cord, pharyngeal slits, an endostyle, and a muscular post-anal tail.
- The notochord is a flexible, rod-shaped body that provides support.
- Chordates include various sub-groups, such as vertebrates, tunicates, and cephalochordates.
Definition and Characteristics of Vertebrates:
- Vertebrates are a sub-group of chordates characterized by having a vertebral column or backbone. This structure replaces the notochord during development.
- All vertebrates possess a well-defined internal skeleton with a spine.
Explanation:
- All vertebrates are chordates because they possess the defining features of chordates during their developmental stages. However, they are distinguished by the development of a vertebral column, replacing the notochord.
- Not all chordates are vertebrates because some, such as tunicates and cephalochordates, retain the notochord throughout their lives and never develop the conditions required to be classified as vertebrates (i.e., a vertebral column).

Given these explanations, the most accurate answer is: Notochord is replaced by vertebral column in adult of some chordates. This accounts for why all vertebrates fall under the category of chordates, but only those chordates with a vertebral column are considered vertebrates.

Answer 2

To understand why "All vertebrates are chordates but all chordates are not vertebrates," let's explore the characteristics and differences between chordates and vertebrates:

Definition and Characteristics of Chordates:
- Chordates form a large phylum of animals that exhibit certain characteristics at some stage of their development. These characteristics include a notochord, a dorsal hollow nerve cord, pharyngeal slits, an endostyle, and a muscular post-anal tail.
- The notochord is a flexible, rod-shaped body that provides support.
- Chordates include various sub-groups, such as vertebrates, tunicates, and cephalochordates.
Definition and Characteristics of Vertebrates:
- Vertebrates are a sub-group of chordates characterized by having a vertebral column or backbone. This structure replaces the notochord during development.
- All vertebrates possess a well-defined internal skeleton with a spine.
Explanation:
- All vertebrates are chordates because they possess the defining features of chordates during their developmental stages. However, they are distinguished by the development of a vertebral column, replacing the notochord.
- Not all chordates are vertebrates because some, such as tunicates and cephalochordates, retain the notochord throughout their lives and never develop the conditions required to be classified as vertebrates (i.e., a vertebral column).

Given these explanations, the most accurate answer is: Notochord is replaced by vertebral column in adult of some chordates. This accounts for why all vertebrates fall under the category of chordates, but only those chordates with a vertebral column are considered vertebrates.

All vertebrates are chordates but all chordates are not vertebrates, why ?

The Correct Option is A

Solution and Explanation

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