Download - Biology 28 1 introduction to the arthropods
28-1 Introduction to the Arthropods
Exoskeleton
• External skeleton; tough external covering that protects and supports the body of many invertebrates.
Chitin
• Complex carbohydrate that makes up the cell walls of fungi; also found in the external skeletons of arthropods.
Appendage
• Structure, such as a leg or antenna, that extends from the body wall.
Tracheal tube
• One of many branching, air-filled tubes that extend throughout the bodies of many terrestrial arthropods.
Spiracle
• Small opening located along the side of the body through which air enters and leaves the body of many terrestrial arthropods.
Book Lung
• Organ that has layers of respiratory tissue that is used by some terrestrial arthropods for the exchange of gases.
Malpighian tubule
• Saclike organ in most terrestrial arthropods that extracts wastes from the blood, adding them to feces that move through the gut.
Molting
• Process in which an arthropod sheds its exoskeleton and manufactures a larger one to take its place.
Key Concept
• Arthropods have a segmented body, a tough exoskeleton, and jointed appendages.
Key Concept
• The evolution of arthropods, by natural selection and other processes, has led to fewer body segments and highly specialized appendages for feeding, movement, and other functions.
Key Concept
• When they grow their exoskeletons, arthropods undergo periods of molting.