Question

In which of the following, haemocyanin pigment is found?
(a) Annelida
(b) Echinodermata
(c) Molluscs
(d) None of these

Answer 1

Hint: After the Arthropoda, this phylum is the second- largest among the invertebrate animals. A variety of fossils of these organisms have been obtained from The ocean floors and almost 60,000 to 100,000 species are found including the ancestral ones.

Complete answer:
haemocyanin pigment is found as molluscs. The respiratory proteins haemocyanin and haemoglobin are present in the animal’s blood.
Haemocyanin is rich in copper and haemoglobin is rich in iron which aids in the transport of materials. Due to this reason, organisms with hemocyanin in their blood have blue colour blood. Majority of molluscs and arthropods have blue colour blood due to the presence of hemocyanin.

Additional information:
- In areas with lesser oxygen concentration such as the ocean floors, the presence of haemocyanin is more beneficial than haemoglobin.
- There are blood pigments other than haemocyanin and haemoglobin such as the hemerythrin and chlorocruorin. There are some organisms which do not have any blood pigments also, such as the echinoderms.
- Snails are terrestrial molluscs and humans are affected by snails in different ways such as making ornamental products, pests in the crop, and as carriers of the disease.
So the correct option is '(c) Molluscs'.

Note:
- Three major universal characteristics differentiate molluscs, which is the presence of a mantle with a certain space that is used for respiration and removing waste materials.
The other two characteristics include the radula and the design of the transportation system. Some other common features include the presence of shells but they are absent in slugs.
- Molluscs shells are also used as embroidery objects and are included in various jewelry. One major reason why their number reduces in the environment is due to this and acidification of oceans.