a) Competition
Competition is a specific interaction between two or more organisms or species, where the ability of one to survive is lowered by the presence of another. An example of competition in the Barwon Heads Rocky Shore environment is between the Soldier Crab and the Notched Shore Crab, where both scavenge on dead animal and plant material. The Soldier Crab has evolved specific features to allow it to compete with the more populous Notched Shore Crab. Because the population of the Soldier Crab is much smaller than that of the Notched Shore Crab, they form in large groups on the sand flats around the Bluff, and emerge as the tide recedes to filter through the sand for food. This behaviour means that combined, they can find enough food …show more content…
An example of mutualism in the Barwon Heads Rocky Shore environment is between the Decorator Crab and sponges. As the name suggests, the Decorator Crab uses sponges and other organisms to coat its body, and therefore camouflage itself and hide from predators. The crab also benefits from this relationship as it can feed on the algae that grows around the sponge. On the other hand, the sponge benefits as it is exposed to a wide range of feeding opportunities, since it is able to move around the shore quicker and easier attached to the crab. This makes feeding easier for the sponges, as most sponges move slowly or stay in the same place, and are therefore exposed to less opportunities to obtain …show more content…
An example of parasitism in the Barwon Heads Rocky Shore environment is between the male Smooth-handed Crab and a shelless barnacle called Sacculina sp. Sacculina depends on crabs for its growth and reproduction. A female Sacculina finds a crab and sheds its hard outer layer. It then enters inside the crab, and uses the crab’s body to obtain energy. Furthermore, the Sacculina causes the infected crab to become infertile, meaning it gains extra energy that the crab would have otherwise invested for