Question

Peripatus is a connecting link between

• A. mollusca and echinodermata
• B. annelida and arthropoda
• C. coelenterata and porifera
• D. ctenophora and platyhelminthes

Hint:

Peripatus belongs to the phylum Onychophora, which shows characters of annelids as well as arthropods. As a result of its resemblance with two different phyla, Peripatus is often referred to as connecting link between them. This shows important morphological and anatomical evidence of evolution.

Answer 1

The Correct Option is B

To determine the correct answer to the question about what Peripatus is a connecting link between, we need to understand the biological concept of "connecting links." These are organisms that exhibit characteristics of two different groups of animals, suggesting an evolutionary relationship.

1. Peripatus is an organism that exhibits features of both annelids (segmented worms) and arthropods (a group that includes insects, arachnids, and crustaceans).
2. Characteristics of Peripatus that are similar to Annelida:
   • Segmented body
   • Soft, non-chitinous cuticle
   • Presence of parapodia (although in a rudimentary form)
3. Characteristics of Peripatus that are similar to Arthropoda:
   • Tracheal system for respiration
   • Jointed appendages
   • Use of chitinous jaws
4. These features make Peripatus a classic example of a connecting link between annelids and arthropods, showing how arthropods may have evolved from annelid-like ancestors.

Therefore, the correct answer is: annelida and arthropoda.

Let’s consider why other options are incorrect:

1. Mollusca and Echinodermata: These are entirely different phyla. No organism serves as a connecting link here.
2. Coelenterata and Porifera: Again, these are distinct phyla with no known connecting links at the level of complexity that Peripatus exhibits.
3. Ctenophora and Platyhelminthes: These do not have known direct evolutionary forms like Peripatus does between annelids and arthropods.