An earthworm (annelida) and a beetle (arthropoda), both have segmented bodies but the beetle has a hard external skeleton. How does the beetle's external skeleton help it survive?
The beetle's hard external skeleton helps it survive in three major ways. First, it provides protection to the beetle's soft internal organs from predators and physical damage.
Second, this rigid outer covering significantly reduces water loss. This adaptation is crucial because it allows arthropods like the beetle to survive in dry and exposed environments without dehydrating quickly.
Finally, the external skeleton supports powerful muscles. This muscle support enables strong and precise movements, further aiding the beetle's survival in diverse and challenging conditions.
Explanation
The textbook explicitly states under the 'Arthropoda' section that the hard external skeleton provides three main advantages: protection, reducing water loss, and supporting powerful muscles. These features collectively allow arthropods to thrive in dry and exposed environments, unlike earthworms (Annelida) which require moist habitats to survive.