Question

Book Lungs are found in-
a. Scorpion
b. Hydra
c. Frog
d. All of the above

Answer 1

Hint: Book lungs are the unique respiratory organs present in arachnids. The book lungs contain sheets like structure appearing to that of a book which are present under the abdomen of the organism.

Complete answer:
> Option (a) Scorpion is correct. Book lungs are the important respiratory organ present in most arachnids like spiders and scorpions. Book lungs are present within a small opening in the abdomen of the arachnid. The book lungs consist of a series of sheets or plates -like structures which are filled with haemolymph. Scorpions breathe through their four pairs of book lungs, which are present under its abdomen. Hence, the

> Option (b) Hydra is incorrect as the hydras breathe by through the process of passive diffusion. The epidermis, which surrounds the hydra, is able to take in oxygen actively from the surrounding water. In return the wastes like carbon dioxide are released in a same way through the epidermis.

> Option (c) Frog is incorrect. The frogs have three types of respiratory surfaces in their body. They are- the skin, in the lungs and mouth lining. While remaining completely submerged in water, all of the respiration takes place through the skin.

Hence, The correct answer is option (A).

Additional information:
Scorpions are arthropods; they have eight legs following two pedipalps and a tail containing venom-injecting barbs. The scorpions have two venom glands which are used in hunting and self defense. Scorpions have an exoskeleton made of chitin, which is similar to that of the shell of a shrimp.

Scorpions have a special type of body part that helps them in hunting and predation. The pincer-like claws that help them to grab and defend against attackers and prey are called pedipalps.

Sometimes, book lungs can be absent. In that case the gases exchange is performed by the thin walls present inside the cavity, called tracheae. These tracheae are thought to have evolved directly from the book lungs as the tracheae in some spiders have a small number of greatly elongated chambers and more of reduced plate like chambers.

Note: The book lungs got its name from its structure that contains stacked plates and has the appearance of that of a closed page of a book. Between the plates or sheets in the book lungs of the scorpion, there are many air spaces. This air space helps the air to circulate around the plates. Gaseous exchange then occurs through the surface of the plates.