Problem 1 - Campbell Biology

Question

Which of the following respiratory systems is not closely associated with a blood supply? (A) the lungs of a vertebrate (B) the gills of a fish (C) the tracheal system of an insect (D) the skin of an earthworm

Step-by-Step Solution

Answer

(C) the tracheal system of an insect

Step 1: Understand the Respiratory Systems

Four types of respiratory systems are presented in the question: lungs of a vertebrate, gills of a fish, tracheal system of an insect, and skin of an earthworm. Each has a different method for exchanging gases with the environment.

Step 2: Examine the Lungs of a Vertebrate

The lungs of a vertebrate are highly vascularized organs, meaning they are closely associated with a blood supply, which facilitates the exchange of oxygen and carbon dioxide.

Step 3: Examine the Gills of a Fish

The gills of a fish are also integrated with a rich blood supply. Blood vessels in the gills pick up oxygen from the water and release carbon dioxide.

Step 4: Examine the Tracheal System of an Insect

The tracheal system of an insect consists of a network of tubes that directly transport oxygen to body cells and remove carbon dioxide, without needing a blood supply.

Step 5: Examine the Skin of an Earthworm

The skin of an earthworm is involved in gas exchange and is closely associated with a network of blood vessels that help in the transport of oxygen and carbon dioxide.

Step 6: Identify the Correct Answer

After examining each system, the tracheal system of an insect is the only one not closely associated with a blood supply.

Key Concepts

Respiratory Systems

Respiratory systems are responsible for gas exchange in organisms, facilitating the uptake of oxygen and the release of carbon dioxide. Different organisms have evolved a variety of respiratory systems suited to their environments and lifestyles. Four major types are highlighted in our exercise: the lungs of vertebrates, the gills of fish, the tracheal system of insects, and the skin of earthworms. Each system is unique in its structure and blood supply association.

Tracheal System

The tracheal system is a specialized respiratory system found in insects. Unlike the lungs and gills, the tracheal system does not rely on a blood supply to transport gases. Instead, it uses a network of tubes called tracheae. These tubes open to the outside through small openings called spiracles. Oxygen travels directly through the tracheae to the insect's tissues and cells. Carbon dioxide follows the reverse path, exiting the body through the spiracles. This direct delivery system allows insects to efficiently meet their metabolic needs.

Gas Exchange

Gas exchange is the process by which oxygen is taken into the body and carbon dioxide is removed. This process is vital for cellular respiration, which produces the energy needed by cells. In vertebrates, this occurs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out. In fish, gills allow oxygen to enter from water while expelling carbon dioxide. In earthworms, gas exchange takes place through their moist skin. In insects, the tracheal system provides a direct path for gases, bypassing the need for circulatory involvement. Understanding these systems helps us appreciate the diversity and efficiency of biological adaptations.