Mollusca and class Gastropod

To analyze the rocky shore ecosystem and the changes in the bio-diversity in the rock pools along the rocky shore as we move from the high tide mark to the low tide mark. HYPOTHESIS: If we move from the high-tide mark to the low-tide mark the bio-diversity will increase. This could be due to the several reasons: 1. The bio-diversity will be more at the low tide mark because, this area being covered in water most of the time has a low saline concentration as compared to the high tide mark. Due to the constant wave action, salt is deposited at the high tide mark and the water close to the low tide mark is continuously replenished.

2. Since the area around the low tide mark is covered in water most of the time, more organisms will be found here because more aquatic animals can thrive in this region. 3. Evaporation of water in the high tide regions will cause the animals to die. This is because, these regions anyways lack water and with evaporation, these animals will dry out. On the other hand, even though evaporation occurs in the low tide regions, there is still enough water present in the rock pools of these regions due to the constant wave action. Therefore, the possibility of the animals drying out decreases.

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

4. The rock pools present in the high tide mark, will have water with very high salinity. This causes the organisms in such pools to die due to plasmolysis in such a hypertonic solution. On the other hand, rock pools near the low tide mark will have water with low salinity. This is because the water in these pools is constantly replenished due to the wave action, thus making the water more suitable for the aquatic organisms to thrive in. 5. The number, the size and the amount of water in the pools will increase as we approach the low tide mark. FACTORS AFFECTING THE ROCKY SHORE:

The following are the factors that affect the rocky shore and even could be responsible for the shape of the rocky shore: PHYSICAL FEATURES:  Salinity Wave force (frequency and the power)  Tide Temperature BIOLOGICAL FEATURES:  Competition for survival amongst the aquatic organisms in a limited area Predation  Human impact ‘Competition and predation play strong roles in the lower, more resource rich zone. This forces some species to live in areas that are sub optimal for their growth and reproduction. ‘1 APPARATUS: ON SITE (AT ROCKY SHORE): 1. Measuring tape 2. Metre ruler.

3. Plastic sieve 4. Surgical gloves 5. Punctured plastic containers for the samples 6. Glass bottles for the water samples 7. Shovels 8. Dry and wet bulb thermometer 9. Clipboard pencils and paper LABORATORY APPARATUS: 1. Intel digital microscope 2. Light microscope 3. pH meter 4. Tongs 5. Petri dishes 6. Slides 7. Cover slips PROCEDURE: On approaching the site we were divided into six different groups between the high tide mark and the low tide mark and the following procedure was carried out: AT THE SITE: 1. A rock pool was identified between the high tide and the low tide mark. 2.

A rough sketch of the pool was drawn. 3. The approximate dimensions of the rock pool were noted. 4. The pool was divided into four regions. 5. The dimension of each region was measured using the metre scale. 6. The depth of each region was also found using the metre scale. 7. The number of each species of plants and animals present in every region was counted. 8. A sample of each species was collected in the empty punctured containers along with the pool water, ensuring that they received enough oxygen supply. 9. A sample of water was also collected in an empty bottle for further research. 10.

The approximate distance from the high tide mark was estimated. IN THE LABORATORY: 1. The sample of organisms was taken and examined under a light microscope. 2. The pictures and slides of various organisms were also taken in order to have a better study of the adaptations of the species in order to survive. 3. Sketches of the collected species were drawn and the adaptations for organisms surviving on the shore were found. 4. The total number of species in the rock pool was estimated. 5. Using the Simpson’s Diversity Index (SDI), the bio- diversity in different pools was found and a comparative study was done.

DATA COLLECTION AND DATA PROCESSING; OBSERVATIONS:  It was noticed that the size of the pools and the amount of water in every pool increased as we approached the low tide mark.  The water was not very clear. It was cloudy and had certain suspended particles in it. Distance of the rock pool from the High Tide Mark = 130m {Estimate} PROFILE OF THE ROCK POOL Dimensions Area Depth Region 1 50 x 55cm 2750cm2 7cm Region 2 130 x 80cm 10400cm2 8cm Region 3 105 x 50cm 5250cm 2 8cm Region 4 90 x 50cm 4500cm2 5cm TABLE SHOWING THE ANIMAL AND PLANT LIFE IN EACH REGION Name R1 R2 R3 R4.

Distance From The High Tide Mark And The SDI Of Each Of The 6 Pools Examined By The Students Distance from the High Tide Mark Simpson’s Diversity Index Pool 1 50 m 3. 3 Pool 2 65m 7. 01 Pool 3 66m 3. 67 Pool 4 80m 4. 21 Pool 5 130m 5. 58 Pool 6 250m 3. 33 INFORMATION ON SOME OF THE ORGANISMS FOUND 1. SHRIMPS: Shrimps are small, marine decapod crustaceans.

Shrimps have 10 jointed legs on the thorax, well-developed swimmerets on the abdominal segments, and a body that is compressed laterally. They are mostly grey or transparent and can grow as long as 9 inches (23cm), but most of them are smaller. Shrimps are well distributed in the temperate and tropical salt and freshwaters. Although they are very tolerant of salinity and pH ranges (down to 6. 0), they are very sensitive to ammonia and heavy metal concentrations, as most of them are freshwater shrimps. They live in temperatures around 30i?? C or below. 2. LOBSTERS: Clawed lobsters comprise a family of large marine arthropods.

Lobster has a tough exoskeleton, which protects it, and it is an invertebrate organism. Like all arthropods, lobsters are bilaterally symmetrical. The anatomy of the lobster includes cephalothoraxes, which is the head fused with the thorax, and the abdomen. The lobster’s head consists of two pairs of antennae, eyes, and a mouth. The abdomen of the lobster includes its 10 legs and swimmerets. The environmental conditions of the lobsters can vary from ocean to ocean, but the lobster’s temperature environment does not fluctuate much, since its home is basically the ocean.

Because a lobster lives at the bottom of the ocean, vision is poor and instead, the lobster uses its antennae as sensors. 3. SNAILS: Snails are terrestrial molluscs belonging to the phylum Mollusca and class Gastropoda, characterized by the animal’s foot being attached to its abdomen. The snail’s soft and wet body is coated in a layer of mucous and consists of a bilaterally symmetrical foot and head, and a coiled, asymmetrical hump that fits into the spire of the shell. Snails have an external shell large enough to enclose the entire animal, enabling them to survive severe conditions of drought, heat and predators.

They have a soft, unsegmented body measuring 2 to 4cm in length with a bearing one to two pairs of tentacles. While the front tentacles are sensitive to odours and sometimes taste, the larger back tentacles have an eye at the end. The foot, located in the abdomen, is the organ of locomotion. They can live for 5 to 10 years, and rarely 15 years. 4. BARNACLES: Barnacles are a type of Arthropod and are distantly related to crabs and lobsters. Emerging more than 520 million years ago, there are around 1,220 barnacle species currently known.