(Robison and Kaesler, 1987) Trilobites had highly-calcified exoskeletons, at a magnitude on-par with ostracodes and other crustaceans. The size, articulation, and morphology of the trilobite exoskeleton are useful descriptors. In some cases, these properties can serve as distinguishing characters; in other cases, minor differences in these properties can exist among genera and even species. Variations in size and morphology of the tagmata may also be used to identify developmental phases in trilobites. (Robison, 1987) According to Robison (1987), an adequate classification scheme for trilobites has not been resolved. The provisional subgroups presented by Robison (1987) are Polymerida (which have mature-looking holaspid forms) and Agnostida (which have juvenile-looking holaspid forms). Superclass Crustacea Crustaceans are predominantly marine arthropods that first appeared in the early Cambrian. They are ecologically diverse, filling the roles of benthic deposit feeders, pelagic and sessile suspension feeders, scavengers, predators. Crustaceans are morphologically diverse as well: segmentation may vary, limbs are typically more specialized than those of Trilobitomorpha and still vary among subgroups. (Robison and Kaesler, 1987) The diversity of crustacean morphology has resulted in a precise classification scheme. The class, Ostracoda, includes small crustaceans (typically less than 1 mm in length) with bivalved carapaces. Like trilobites, ostracod carapaces are highly…
bivittatus to be very cautious at first. They would run to little hiding holes and some of the larger ones had nests to protect. I noticed which crevices were nests by marking rocks with a knife and taking notes of markings on fish such as scars and coloration. After awhile of being underwater they began to become more curious of me and came out of hiding. After 30 minutes on my first dive observing them, they didn’t seem to mind my presence at all, some of the larger males would even swim up to…
integrity of the author. He establishes his credibility in these main ways: having a clear statement of participation and by dedicating a section of his article to scientific descriptions. First, Wallace, in no unclear terms, declares that he physically attended the festival. In doing so, the immediate response to, “Your assigned correspondent saw it all, accompanied by one girlfriend and both parents…,” is that of an “insider’s” perspective. For example, if someone was curious about the…
the valve in 2002, the increased salinity in these three areas has allowed for marine and estuarine fauna to reinhabit the marsh (Smith & Medeiros, 2013). However, East Harbor has only been partially restored because an additional small culvert under High Head Road that connects Moon Pond to the Main Lagoon (Thiet et al. 2014) is too small to create significant tides in the Main Lagoon (Portnoy, 2006). Despite this, benthic invertebrate diversity and density have increased significantly (Thiet…
mollusks, oxygen utilization is relatively high—up to 70 percent of the oxygen is extracted from the water passing over the gills in the European crayfish Astacus. A decrease in the partial pressure of oxygen in the water elicits a marked increase in ventilation (the volume of water passing over the gills); at the same time, the rate of oxygen utilization declines somewhat. Although more oxygen is extracted per unit of time, the increased ventilation increases the oxygen cost of breathing. The…
and their abdomen is located in what is commonly thought of as the tail. They have long bodies, covered with a segmentented outer skelton. Crab also have 10 legs, including the claw bearing ones. It 's not uncommon for the right claw to be larger than the left one. Some of the legs are flatter than others, to use for swimming instead of walking. Jellyfish have no skeleton, instead having soft, colleganogous bodies with tendrils. Analysis and Interpretation All six orgaisims share similar…
Introduction The diversity of arthropods extends beyond the location factor alone as multiple influences such as humidity levels, atmospheric content and other environmental conditions contribute to their widespread assortment. Gaps in diversity indices do not only occur amongst insect populations residing at regionally distinct locations as these influences are also reflected in arthropod communities over small distances. Climatic conditions often lead to insect migrations and extinctions which…
Do Cnidarians replace their stinging cells once used? Many people are familiar with the Jellyfish sting. When a jellyfish brushes against someone and they feel pain, they are feeling the cells along the jellyfish's tentacles referred to as cnidocytes. These cells harbor tiny projectiles full of venom, called nematocysts. There are many questions about the sting of the jellyfish, the structures involved, and the venom delivered. Specifically, do Cnidarians possess any capabilities of…
The Homarus americanus also known as the true lobster, the northern lobster, and the Maine lobster play a imperative role in the ecosystem. They are a ample source of food for America and all around the world because fishermen harvest such preponderant amounts lobster. Sometimes they are over fished so places such as the European Union, Canada, the U.S, and New Zealand are starting the manage the amount of lobsters harvested so that fishermen do not deplete the source. The reason they are so…
of every five Filipinos have diabetes and Filipinos who were diagnosed are getting younger. In fact, children as young as five years old have been diagnosed with type 2 diabetes. It is concluded from the experts that the increase of diabetes cases in the Philippines are due to their lifestyle and culture. Also, the cost of different vices such as cigarettes and liquors sold in the Philippines are very cheap. It is no wonder that the incidence of diabetes in the Philippines will get worse in the…