Chapter 29, Problem 3A

Summary Introduction

To write:

The correct term by replacing the given word in italics.

Introduction:

Reptiles were the first completely terrestrial vertebrates and are fully adapted to live on land. Characteristics like scaly skin, circulatory and respiratory system and shelled egg allow them to succeed on land. They have common characteristics with other organisms such as the presence of an amnion and other membranes.

Explanation of Solution

Snakes belong to the order Squamata. They are legless and have shorter tails than lizards and lack movable eyelids and tympanic membranes. They have joints in their heads enabling them to eat prey that are larger than their heads. Reptiles have a highly evolved sense of smell. Snakes detect odors by flicking their forked tongues. The molecules of odor bind to the tongue which the snake then places in its mouth. The odor molecules are moved to a pair of sac-like structures known as the organs of Jacobson located on the roof of the mouth. They help the snakes to sense odors.

Conclusion

The Jacobson's organ is responsible for the sense of smell in snakes. Thus, the correct term for the given word in italics is Jacobson's organs.