Adaptation

Mesodon elevatus has adapted in specific ways to its environment many of which can be expressed through generalization of all pulmonates.


    The most noticeable and defining adaptation of the land snails is the large unsupported unbalanced shell that they have. Gastropods will move for a variety of reasons such as for food, finding mates, and can scatter if necessary. In order for movement they use adhesive locomotion (Barker, 2001). When moving land snails lay down water like mucus and use that to move over. Their mucus also allows for attachment due to its adhesive properties (Fretter et al. 1975). Pulmonates in particular used their muscular organ the foot that has a large sole, which they use for crawling (Fretter et al. 1975).  Land snails have developed certain adaptations or live in certain places in order to preserve water. For example, they provide heavy protection for parts of their body’s wet surfaces; they also will avoid temperature extremes. Therefore temperature along with altitude, soil texture, and areas of shelter are all determining factors of gastropods habitat (Barker, 2001). Not only have gastropods adapted ways to move, but how they gather food, mates and shelter as well.


            In order to access food, mates, and shelter pulmontes use their sense organs one of which is the eye. Their eye consists of a cornea, lens, and a retina (Fretter et al. 1975). Their cornea is made up of large cells in front of the eye that helps direct light on to the retina (Fretter et al. 1975). The retina contains few sensory cells over a large area, for this reason it is believed that pulmonates do not have great vision but they are able to use their vision to detect light intensity and navigation (Fretter et al. 1975).


            Besides their eyes mollusks have aquired other sense organs.  For example, pulmonates also have two statocysts that are located on both sides of the head between the pleural and pedal ganglia (Fretter et al. 1975). These are used to coordinate their movements, orientate themselves, and sense vibrations (Zaitseva, 2001). They are hollow, and are filled with liquid. There is an outer covering of connective tissue that contains large hair cells and also smaller cells (Fretter et al. 1975). The statocysts are also directly connected to their brain like structure the cerebral ganglia (Zaitseva, 2001). Although these are relatively simple structures they are essential to pulmonates for finding food mates and other vital components of their life.

 

 

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