Characteristics Of The Horseshoe Crab

Biologists Robin Seeley conducted an experiment in which she gathered periwinkle snail shells on Appledore Island and measures their thickness. The time period in which she has found the snails was before the inhabitation of the European green crab. Eighty years later, the shell thickness of the snails were measured again and recorded. This time, the inhabitation of the european green crab has increased significantly and the thickness of the snail shells has increased. She has concluded that when the crabs arrived on the island, they began to eat the thin shelled snails because their shells were easier to crack.

You scratch Giant Crab 1 in the left first leg from behind, fracturing the chitin and bruising the fat!

The profile of Pallarenda beach as shown in figure 1 is very typical of a North Queensland, medium energy beach. The lack of organisms present higher up the beach was due to the harsh conditions at low tide. Ghost Crabs, Ocypode quadrata, can survive these areas as a result of their adaptations (The Otter Island Project). The ghost crab burrows during the day and feeds at night to avoid the heat of the day (The Otter Island Project). These crabs can actively take up moisture from damp sand to wet their gills (The Otter Island Project).

The horseshoe crab and the trilobite do share a common ancestor. There are many pieces of evidence in the anatomy of both species that support this claim. A first piece of evidence is that both species have an outer exoskeleton but no internal skeleton. This separates both of them from vertebrates, making both of them invertebrates. The second piece of evidence supporting walking legs of both species are also positioned on the underside of the animal, protected under the shell. Both the trilobite and the horseshoe crab have one horseshoe-shaped cephalothorax with a raised ridge in the middle of it and two eyes positioned on either side of the ridge. The mouth of both species is on the underside of the body as well, unlike crustaceans and insects

The Callinectes sapidus also known commonly as the Maryland Blue Crab, is a crustacean found in the Chesapeake Bay. The blue crab is found in aquatic environments, most often in estuaries. It characterized by it’s blue claws. The blue crabs undergo a life cycle of: zoeae, megalop, juvenile, and adulthood. The blue crab’s hard shells serve as a protective barrier for external dangers. The Callinectes sapidus comes from the order of Decapods, whereby it’s carapace has now evolved to be better suited for swimming. Of interest is the blue crab’s mating

Horseshoe crabs are an important part of the wetland ecosystem, however they are going extinct. Due to harvesting, pollution, and other animals consuming their offspring their numbers are dwindling. They play an important part in the ecosystem and need to be protected so they do not become extinct. The Delaware bay has decided to protect them for their future uses in medicine and to keep them as an important role in the ecosystem.

This perspective often distorts the view of large crabbing businesses on their harvesting methods which, although are seemingly humane, are actually very detrimental to the crab population. For instance, when Hal Herzog, a Professor of Psychology at Western California University, ventured to Florida’s Gulf coast, the crabbers there explained to him the two varieties of crabs which they harvested; the “lucky” stone crabs and the “unlucky” blue crabs (Herzog). The blue crabs were considered unlucky because they were killed on the spot; however, the stone crabs were considered lucky because of their ability to regenerate their claws, and so crabbers would simply rip their claws off and then throw them back into the sea (Herzog). However,

In a broader study of several national parks in Alaska, conducted in October 2009 by Robert B. Blodgett and David. M. Rohr, documented the varied and abundant marine invertebrate fossils. The team studied Paleozoic and Mesozoic marine faunas in Wrangell-St. Elias National Park, Denali National Park, Yukon-Charley River National Preserve and Glacier Bay National Park. They found that upper triassic gastropods from the chitistone limestone in Wrangell-St. Elias included a wide variety of early norian gastropods very similar to the fauna of the Hells Canyon region of the boundary of Oregon and

We use fossils to compare and contrast how and organism has evolved over a long period of time and how it has adapted to new changes.

Studies have found information on ancestral species of current horseshoe crabs. Xiphosurids, which are very old fossils that were not easily found; however, they were compared in body structure of current time horseshoe crabs and showed that there was hardly any change in the body structure. The body plan of a xiphosurid is described as having large crescent like shield in the anterior portion of its body resembling an invertibrate with lateral compound eyes. Xiphosurids are also classified as having opisthosomal tergites built into a thoracetron and having a long styliform telson (Rudkin et al. 2008).

The blue crab Callinectes sapidus is a wide-ranging, ecologically and economically important species along the Atlantic and Gulf of Mexico (GMx) coasts of North America. Consequently, its basic biology, life history, population genetics, and demography have been the subjects of numerous studies. For my dissertation research, I propose to focus on two critical areas concerning the ecology and evolution of blue crabs that have broader implications for our understanding of marine organisms with biphasic life cycles. For the first chapter I will investigate the unusual finding of extreme temporal and spatial variation in the genetic composition of settling blue crab larvae along the Texas coast. Since it was reported in 1993, this finding been

The Caribbean Spiny Lobster, a uniquely adorned decapod, is found in subtropical to tropical waters, inhabiting rocky crags to sponges to sea grass. A carnivorous species, they will feed on gastropods, sea urchins, worms, and crustaceans. In addition to this, they are also important aquatic scavengers, aiding in the process of decomposition of dead organisms that fall to the ocean floor (Kanciruk 1980). Commonly fed on by moray eels and nurse sharks, they play a significant role in the food chain for not only marine species, but for humans as well. According to the FAO Fisheries and Aquaculture Department, this is one of the most important Palinurid species that is harvested in American waters due to high demand (Holthuis 1991). The economic

Lobsters were once the biggest organism on the earth. Aegirocassis benmoulae was the name of this massive beast. It had lived around 480 million years ago. It had fins on the body on the bottom of its body. It has adapted to its surrounding by using claws. It uses its claws to snatch food. Also to fight off attackers. The lobster also has a hard shell to protect itself. These are some fascinating adaptions of the lobster.

The Uca genus is comprised of fiddler crabs. There are currently 120 different extant species found worldwide. The members of the Uca genus can be found near the Eastern Atlantic, Western Atlantic, Eastern Pacific, and Indo-West Pacific (Rosenberg, 2014). This review will focus on eight species found in the Continental US: Uca burgersi (Saltpan Fiddler Crab), Uca crenulata (California Fiddler Crab), Uca minax (Redjointed Fiddler Crab), Uca pugilator (Atlantic Sand Fiddler Crab), Uca pugnax (Atlantic Marsh Fiddler Crab), Uca rapax (Mudflat Fiddler Crab), Uca speciosa (Longfinger Fiddler Crab), Uca thayeri (Atlantic Mangrove Fiddler Crab).

In his 1988 Supreme Court opinion in Hustler Magazine v. Falwell, the late Chief Justice Rehnquist argued, “the art of the cartoonist is often not reasoned or evenhanded, but slashing and one-sided...the political cartoon is a weapon of attack, of scorn and ridicule and satire...it is usually as welcome as a bee sting”. Despite these biting words, the Court ruled that political cartoons are essential tools in a democracy. Political cartoons are inherently controversial, as they seek to mock both the legal and governmental process. However, they are also inherently American, as they reflect the core tenets of the First Amendment, the right to free speech, and expression. In this paper, I will analyze a political cartoon, created by the artist Paul Conrad in 1972 for the Los Angeles Times. I will first provide a description of the cartoon, its relevance at the time, and the political salience that it still maintains today. Secondly, I will examine this cartoon through five intersecting lens: the efficacy of visual rhetoric/graphic discourse, materiality, technology/modernity, power, and institutional/male domination. Through these lenses, I will trace my object's physical and ideological genealogy, and examine its social, political, and historical significance in contemporary culture.