Question

Which one of the following statements is INCORRECT with respect to the tree of life?

• A. Ctenophora is more closely related to Cnidaria than it is to Echinodermata.
• B. Porifera is more closely related to Ctenophora than it is to Echinodermata.
• C. Arthropoda is more closely related to Tardigrada than it is to Annelida.
• D. Arthropoda is more closely related to Mollusca than it is to Nematoda.

Hint:

When analyzing evolutionary relationships, remember that molecular data often provides a clearer picture of phylogenetic relationships than traditional morphological similarities.

Answer 1

The Correct Option is D

The question asks us to identify the incorrect statement in terms of the evolutionary relationships among various phyla. Let's evaluate each statement:

Step 1: Evaluate each statement.
- (A): Ctenophora and Cnidaria are both part of the group Radiata and share a more recent common ancestor with each other than with Echinodermata. This is correct.
- (B): Porifera (sponges) are more closely related to Ctenophora than to Echinodermata. Porifera is a basal group, and Ctenophora and Echinodermata are both more derived, but this relationship is supported by molecular data. This is correct.
- (C): Arthropoda is more closely related to Tardigrada (water bears) than to Annelida. Molecular phylogenies support the idea that arthropods and tardigrades are more closely related, forming a group called Ecdysozoa. This is correct.
- (D): This is incorrect because Arthropoda is more closely related to Nematoda than to Mollusca, according to current phylogenetic studies. Arthropoda and Nematoda both belong to the group Ecdysozoa, while Mollusca is part of a different group, Lophotrochozoa.

Step 2: Conclusion.
Therefore, the incorrect statement is (D).