The ‘Purple Shore Crab’ (Hemigrapsus nudus) is a tiny crustacean that inhabits the mid to low zone of the Rocky shore. This location is an intertidal zone, meaning that the organism lives in a very harsh environment. These crabs, as the name suggests, are purple in colour, with reddish-purple spots on their claws. They are known as decapods, because they have 10 legs (the first pair is modified into claws), and unlike many other crab species they do not have hairs on these legs. Crabs are invertebrates meaning that they have a hard exoskeleton (shell), they are also cold blooded meaning that they take on the temperature from their surroundings, as opposed to trying to maintain a general temperature (warm blooded). Purple Shore Crabs are omnivores, …show more content…
An aspect of this internal system is the circulatory system, which is responsible for transporting the blood throughout the body, that is delivering oxygen and nutrients to the cells (required for respiration), and removing carbon dioxide (byproduct of respiration) as these are transported through the blood. The circulatory system works closely together with the gas exchange system which is the specific process of diffusion in which the oxygen and carbon dioxide move across membranes. The overall effect of these systems is that the crab’s cells will be able to complete respiration, and be able to produce energy from this. This process begins when water enters the crabs gills, at an opening located under their claws. The oxygen dissolved within the water, will diffuse into the lamellae (which contain blood vessels) located on the gill filaments, and the carbon dioxide will diffuse out with the water that exits the crabs mouth. The bloodstream then carries the oxygen to the heart, where it is pumped around the body to the cells that will use it for …show more content…
It also enables them to inhabit the rocky shore, because for approximately half the day, they are submerged underwater, and without the efficient countercurrent exchange system for getting a large amount of oxygen from water, it would be a great struggle for them living in this habitat. And this habitat comes with its advantages, because it is a hard place to live there are fewer organisms here, and the ones that are there don’t tend to be predators of the crab, eg. mussels, anemone and barnacles. However this system works most efficiently when the crab has access to water (ie. submerged), but because they inhabit the rocky shore, they don’t always have access to water. This means that their systems will only work this efficiently for half of the day (during high tide), or when they can access water, and when they don’t have water they will not be able to do gas exchange. However they do have another adaptation that allows them to do this without being submerged (mentioned
The yeti crab is an interesting creature when it's around its surroundings. The yeti's association with their bacteria is more developed than its relatives. Each species has its own system, but one has a comb with which it can extract its food from its setae! The radiation of the closely related species seems to have been in the Coenozoic. This means that, 65 million years ago, as mammals began to take over on land, the types of crab represented now by the yetis began taking over hydrothermal vents and similar niches from a lost generation of previous inhabitants.
The crustacean moult cycle is initiated when the Y-organ in the head secretes the hormone Ecdysone (E) into the circulatory system[3,4,5]; the Y-organ is the primary source of E[5]. Upon contact with the haemolymph (a combination of blood and tissue fluid) within the circulatory system E is converted to its active form, 20-hydroxyecdysone (20E), by a P450 enzyme[4]. This causes the epidermal cells to secrete moulting fluid, which contains a mixture of enzymes such as proteases and chitinases. The moulting fluid degrades the exo- and endocuticle, and the digested cuticle is reabsorbed to create new cuticle; moult fluid also has a role in initiating the moult. The degraded cuticle is replaced by water or air so that the animal can swell in order to lose the shell. During the passive phase of the moult cycle, the shell splits along the break point caused by the decalcification of the shell, in the crab this is along the epimeral lines. Once the shell has split, the animal wiggles side-to-side to free itself from i...
The picture above shows the vast difference that there can be in animals, to the right is Emerita Analoga (sand crab), and to the left is Zalophus Californianus (California Sea Lion). The sand crab is an invertebrate while the seal is a vertebrate and mammal. Invertebrates make up 90% of all an...
The Sacculina carsini, or parasitic barnacle, makes it’s host a green crab, also known as the Carcinus maenas. The parasite in this relationship changes the host’s behavior. It also enables itself to survive, spread and continue this cycle. As talked about in “The Parasitic Sacculina That Bends Its Host to Its Own Will”, when a female barnacle is still in its larval stage, it finds a crab host, and it locates a certain joint in the host’s shell. When there, the parasitic barnacle sheds her outer shell and puts herself inside the crab. Once she is inside, she is in a slug-like form. She creates a root system of tendrils, which extend throughout the abdomen of the crab. The root system takes over the crab’s intestine, diverticulae and surrounds the stomach. This
They also look after the quality of coastal waters by watering down, sifting, and settling deposits, left-over nutrients and contaminants. They are highly productive ecosystems and provide habitats and act as nurseries for all manner of life.
The location is one of the most critical factors to analyze thoroughly because it helps predict whether the sales of the choosing location will be good or not? Although the Boiling Crab is in the growth stage, it still has to focus on new locations that the owner plan to extend to these areas. As I mentioned in the introduction, the owner plans to open the Boiling Crab in four new locations soon.
The sessile consumers are those that are stationary and all feed off small plankton creating competition for their food source which allows some sessile consumers to be more dominant than others. Mussels are the most dominant between the sessile consumer with the Starfish as its predator, followed by Goose Neck Barnacles whose predators are Whelk and Starfish, and Acorn Barnacles whose predators is Whelk. The mobile consumers consist of Whelk(Nucella), Chiton(Katharina), and Starfish(pisaster). The mobile consumers, which are the the species that have a possibility to be the Keystone species are predators and compete for food. The Starfish preys on Mussels and Goose Neck Particles, the Whelk generally prey on Acorn Barnacles and Goose Neck Barnacles, and the Chiton prey on Nori Seaweed, Black Pine, and occasionally Coral Weed. Between the Mobile Consumers the only competition for food is between the Whelk and Starfish who both prey on Goose Neck Barnacles. Lastly, there is the invasive species known as the Green Crab (Carcinus) which has invaded the environment. The Green crab invades the area and is a predator to all
The bay's harvest and many of its other attractions bring tourists and in turn revenue for the area. Oysters and blue crab are a big part of the culture in the bay area. However, these organisms are in danger and need help. Description of the problem Eutrophication is a concern in the Chesapeake Bay. Eutrophication is caused by excessive amounts of nutrients.
Imagine a creature that has a skeleton on the outside of its body, that has eyes that protrude on stalks, and whose blood doesn't flow through blood vessels but, instead, pools and surrounds body tissues. What is this monstrous creature? What if I were to tell you this isn't a monster, but something you've probably seen and maybe even eaten?! Yep, this strange creature is a __crustacean__! There are over 50,000 species of crustacean and they come in all shapes and sizes, from an ocean-dwelling crab to an immobile barnacle! But before we delve into the types of crustaceans, let's take a moment to go over the characteristics and anatomy they share.
The objective is the structural and functional examination of the Trinidad mountain crab (Pseudothelphusa garmani) lung. Unlike most crustaceans, Trinidad mountain crab are considered land crabs, and are not committed to water breathing. Trinidad mountain crabs can air-breathe due to the development of a large blood sinus from invaginated branchial chamber epithelium, forming the respiratory airway to the “cutaneous lung”. The lung of the Trinidad mountain crab has two airways for gas exchange: a primary respiratory airway consisting of alveolar sacs and a smaller secondary respiratory airway. Blood entering the branchial chamber epithelium can either go through the branchial epithelium found in most crustaceans or undergo lung perfusion when
To begin with, the horseshoe crab, one the world’s oldest living creatures, are quite active. This fascinating crab has ten small walking legs under a strong, sturdy exoskeleton, a long spine in the abdomen, and a long pointy tail in the back used to push itself back up after being flipped on its back (Swinton, 99). Furthermore, horseshoe crabs got their name in an interesting way. The crab’s arc shaped exoskeleton, or shell, was compared to a horse’s shoe (Horseshoe Crab: Saint Louis Zoo). As mentioned before horseshoe crabs aren’t actually crabs. Though it may look like one, they are actually part of a family called Limuli. Some reasons it could have been misconceived as a crab are because its shell is comparable to a crab’s, the legs look a bit similar, and they are found on the Atlantic coast like other crabs. Also we can find horseshoe crab right here in North America along the hot, sandy Atlantic
littoria can be summarized as “ephemeral algae that typically lack chemical and morphological defenses” (Dolecal, 2013), making it well suited for the algae abundant upper-tidal. The simultaneous existence of the invasive species H. Sanguineus is evidence to the opportunistic nature of specific niches, as the Asian shore crab is not a native to this rocky intertidal. Researcher John Tiedemann observed the presence of H. Sanguineus along the Barnegat Bay region of New Jersey, as the invasion is evident along multiple coasts in Northeastern United States. Citing research from 1988, he states that “adult Asian shore crabs tend to favor low energy intertidal shorelines consisting of a variety of material, from cobble to boulders (Fukui, 1988). Originally, they were reported to primarily occur in the middle and upper intertidal zone (Fukai, 1988; McDermott, 1992, 1998)” (Tiedemann 2015). This record of typical location for H. Sanguineus implies that it is encroached on/adjacent to much of the intertidal areas that are occupied by L. littoria. It is probable that Asian shore crabs reside in the algae abundant areas of the Rocky Intertidal in order to maximize their predation of Periwinkle
This research focuses on Gambierdiscus toxicus which is an armored, marine, benthic species in the phylum Dinoflagellata. It has an epitheca and a hypotheca, that is very similar in size, compressed anterio-posteriorly. The theca is covered with numerous deep and dense pores which are very thick. This species is autotrophic creating energy via several golden-brown chloroplasts (Hackett et al 2004), but is also heterotrophic and hence is referred to as mixotrophic. It has a ventrally – oriented crescent shaped nucleus. (Adachi & Fukuyo 1979). It usually inhabits warmer waters such as bay, mediterranian, tropical/sub – tropical in North/Central America (Shiumuzu et al 1982; Loeblich & Indelicato 1986), Asia/Pacific (Holmes & Tao 2002; Lu & Hodgkiss 2004) and has recently been identified in the Mediterranean (Aligizaki & Nikolaidis 2008). These authors identified the organisms to genus level, at best of their effort, so may have been one of the less common members of its genus although it is unlikely.
Pea crabs, from the family Pinnotheres pisum, are kleptoparasites found around the world's oceans in different Bivalve mollusks species, specifically oysters and mussels. These soft-shell crabs are natural occurring pests, they were not brought or transported by humans around the world but rather evolved to infest mollusk species for food and protection. Their life cycles start at being birthed in areas where oysters or mussels are born in the previous or same year. The timing of the two species is offset to give the mollusks time to grow big enough to hold the crab juvenile. Once inside, the crab sits right next to the feeding filters of the mollusks and eats. If there is enough food being filtered, the mollusk is hardly affected by the presence of the pea crab, but with less food, the mollusk's health starts to decline, though they won't die, because the crab must eat first. The carbs cause damage to the mollusk's gills and the mollusk
Amir was an Indian immigrant who owned a small fabric store in Cliveland and liked to work in the garden. Starting his story with a comparison between American and Indian cities, Amir gave us an example with “million crabs living in million crevices.” Definitely, he did not refer to real crabs; he was talking about people who lived in America, and about their attitude toward others. In my opinion it is fair to describe American cities as Amir did since here, people are too busy with their problems and do not care about their fellow citizens. A person here is either a friend or a foe. Even if American cities have a dense population, people are too distant to each-others. In contrast, Amir described people in India who are more friendly and respectful. India is known as a country with an old culture, where people respect each other and treat everybody in a polite way. Thus, I agree what Amir said about American cities since people who lived in here are like crabs in crevices.