Although having evolved independently, the tracheal tubes of mammals and insects are both supported by rigid tissues. The trachea of a mammal is supported by cartilage, and the tracheae of an insect are supported by chitin. What selective pressure most likely led to the convergent evolution of these respiratory structures?
A) Both mammals and insects have similar oxygen needs.
B) When air is the respiratory medium, there is a greater risk that the tracheal tubes will collapse.
C) Insects and mammals both keep their internal temperature constant.
D) A decrease in environmental carbon dioxide made structural support necessary.

Question

Quizplus · Accepted Answer

The risk of collapse is a common problem for respiratory structures that rely on air as the medium for gas exchange. Both mammalian and insect tracheal tubes faced this challenge, which likely selected for the evolution of rigid support structures to prevent collapse.

Although Having Evolved Independently, the Tracheal Tubes of Mammals and Insects