Adaptation

Gastropods have undergone many adaptations to increase their fitness and chance of survival. Since their soft inside is preyed on by many other organisms, adaptations were necessary to increase fitness and chances of survival.

One of the most noticeable changes is with the structure of the shell. The shell is secreted by the mantle and is made of calcium carbonate that protects the snail from predators, weather, and drying out (Klappenbach, 2012). The shell of a snail has underwent coiling, it is simply the way a snail grows. Besides the shell adapting, the soft body of snails have undergone a 180 degree twist referred to as torsion (Hickman et al., 2009). Torsion results in the anus and mantle cavity opening above the head and mouth so there is only one opening to protect (Hickman et al., 2009). This adaptation is most likely for protection of the Gastropod; because before torsion, the anus and mouth openings were on opposite sides (Hickman et al., 2009). In addition, terrestrial land snail shells contain teeth and lamella that prevent predators from feeding on the inside flesh part of the snail (Dourson, 2010). The shell is also attached to the columnella muscle, which allows the snail to pull its body inside for protection when danger is present (Dourson, 2010).

Gastropods eat a variety of plants, fruits, vegetables, and even parts of rocks and dirt. It was useful for the snails to develop a food processing organ called a radula for feeding (BioExpedition, 2012). The radula allows the snail to grind and rasp down food in order to digest it. Since snails mainly resort to grinding on rocks to get proper amounts of calcium for their shell, a tough organ is helpful to grind down the rock.

Terrestrial snails  have also developed a more advanced sensory system through adaptations. Gastropods have a specialized nervous system consisting of nerve cords connecting numerous pairs of ganglia (Gillis, 2012). Terrestrial gastropods have also adapted to developing eye sensory organs on the ends of their two tentacles (Animal planet, 2008). The eyes are capable of moving up and down as well as side to side in order to view its surroundings (Animal planet, 2008).

As well, terrestrial land snails, like Patera clenchi, have developed lungs for breathing. The walls of the mantle cavity have developed an air sac referred to as a lung (Bioexpedition, 2012). The highly vascularized mantle cavity expands and contracts for gas exchange.


Continue here to learn about how Patera clenchi get their nutrition!

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