The earthworm is a well-known animal that lacks lungs.
While many animals rely on lungs for respiration, others have evolved different methods for obtaining oxygen and releasing carbon dioxide. Earthworms, for example, breathe through their skin. This cutaneous respiration relies on the diffusion of gases across a moist surface. The earthworm's skin must remain moist to facilitate this gas exchange.
Here's a breakdown:
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Earthworms: Utilize cutaneous respiration, where oxygen diffuses through their moist skin into their circulatory system.
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Other Examples: Some insects use a tracheal system, a network of tubes that deliver oxygen directly to tissues. Certain amphibians can also absorb oxygen through their skin, especially when submerged in water. Simple aquatic animals, such as sponges and jellyfish, also lack lungs and rely on diffusion across their cell membranes.
Therefore, the absence of lungs is not uncommon in the animal kingdom, with various species adapting alternative respiratory strategies to thrive in their respective environments.
