Hastings Point Lab Report

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Introduction For two days, on the 14th and 15th of April, a field excursion to Hastings Point, New South Wales was conducted. At Hastings Point, topography, abiotic factors and organism distribution were measured and recorded, with the aim of drawing links between the abiotic factors of two ecosystems (rocky shore and sand dunes), the organisms which live in them, and the adaptations they have developed to cope with these conditions. Within these two ecosystems, multiple zones were identified and recorded, and this report also aims to identify the factors and organisms associated with each zone. Lastly, using data and observations from the past, predictions for the future of the rock pool ecosystem were made. Evaluation If the excursion were…show more content…
The black nerite was observed 76 times in the upper 25 meters of the rock pools, which has been defined as the supralittoral zone. The black nerite has adapted in many ways to successfully survive the harsh biotic and abiotic conditions associated with the supralittoral zone. The supralittoral zone has a categorically large amount of predation, and the black nerites have adapted structurally to deal with this. They have developed a tough, dark shell which not only prevents predators from accessing the snail inside, but acts as a camouflage, matching the dark coloured rocks. This tough shell also helps the nerites survive in the often dry and hot supralittoral zone, where a decrease from 83%RH to 75%RH was seen at Hastings Point. This adaptation is to retain moisture using a special structure – the operculum – which can be sealed when the snail is not eating to retain moisture within the shell. This is used especially between the high tides, as water only reaches this high zone at these times. Another factor associated with the supralittoral zone is harsh wind conditions, which was observed at Hastings Point where the temperature indicated a 12% increase in average temperature between the littoral and supralittoral zones. The black nerites adapted behaviourally to survive these conditions. To do this,…show more content…
70 common limpets were identified in the 40m bracket identified as the littoral zone, between 0m to 40m. The common limpet employs a range of adaptations to survive the abiotic and biotic conditions associated with the littoral zone. Firstly, the limpet uses a structural adaptation to overcome the harsh wave action in the tidal zone, by using their radula to grip on to imperfections in the rock. Furthermore, they employ a behavioural adaptation of grinding their shells down into the rock, to further ensure they are not swept away by the tide. Additionally, the limpet utilises a behavioural adaptation regarding its tough shell and powerful radula, to defend against predators. This predation was seen at Hastings Point, where the limpet’s main predator, Morula marginalba (mulberry whelk), was identified 25 times in the first 35m. To survive this predation, the limpet utilises its tough clutch on the rocks, defending itself against predators by trapping them under the rim of its shell, consequently killing or starving the

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