One example of adaptation exhibited by oysters is their hard shell, which protects the mollusks from predators. Additionally, as inhabitants of the harsh intertidal zone, where the temperature and water levels fluctuate, oysters have evolved physiological mechanisms to cope with these challenges. According to a study published in the journal “Nature,” oysters have genes that help them cope with the high stress levels caused by the constantly changing climate.
Most of the oyster’s adaptations have evolved in response to their sessile lifestyle. Oysters are similar to plants in this regard, as they cannot travel to obtain food and they must withstand the local environmental conditions. One way oysters have adapted to this lifestyle is by becoming filter feeders. Oysters filter the water in their habitat, retain any organic material and expel minerals and excess water.
The hard, calcium-based shells of oysters dissuade predators such as octopuses, fish and crabs. The process by which bivalves produce their shells is not fully understood, but like most other bivalves, oysters rely on two different abductor muscles to open and close their shell. A large tendon has evolved to connect the two halves of the shell.
Some oysters are well known for their habit of generating pearls. This occurs when the creature applies layer after layer of mother of pearl to a piece of debris that becomes trapped inside the shell.