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 …show more content…
enables the barnacle to take nourishment from the crab. Other tendrils also envelope the crab’s thoracic ganglion, or nerve center. These tendrils follow the crab’s nervous system through its legs and also surrounding the cerebral ganglion, or brain of the crab. After a few weeks pass, the barnacle develops a reproductive structure that grows near the rear of the crab, in it’s abdomen. At this location, male larval barnacles enter into the female’s reproductive structure and produce sperm to fertilize the eggs. The female can make hundreds of eggs every day. The parasites can live in the host until the host dies, so they can continue to breed for at least 1 or 2 years. It takes about 6 weeks for the eggs to develop into larvae. This reproductive cycle continues until the death of the host.
The barnacles not only live and reproduce inside the host crab, but they control it. The tendrils attached to the nerves produce substances that change the crab’s endocrine system. This leads to the crab’s body absorbing its own Y-organ. The Y-organ instructs the crab to molt or grow. The crab’s androgenic gland is also degenerated. The androgenic gland controls sex differentiation. At this point, the crab is unable to grow, molt, regenerate lost limbs and it is infertile. When the barnacle inhabits a male crab, the changes feminize him. The male crab will resemble and act like a female. He may even perform a female mating dance. After all this has taken place, the host crab will take care of the parasitic eggs. The crab acts as if the eggs are its own. At the right time, the crab will climb up onto a high rock, and tend to the egg pouch, as it would do in its own reproductive cycle. When the generous number of eggs are ready to hatch, the crab will bob up and down in the water to release them. The crab will then mix the floating eggs with it’s claw to set them on their way. These larvae will usually find new hosts, which continues this
cycle.
[8.3] In what ways do you think your results would have been different if you had sampled at a different height on the rock?
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...
Squidward Tentacles is an employee at the Krusty Krab. He is a 34 year old male. He resides in Bikini Bottom. His hobbies include playing his clarinet and painting multiple pictures which he has false hope will one day be published in some museum. He has hatred for going to work, and is horrible with customer service. He exhibits a strong desire to fit in with a higher caste than himself. There have been many episodes though where when given the chance to prove himself worthy of a higher caste he will retreat to a safer place like his house. His esteem level seems very low. He never leaves his house other than for work either. He hates being social and that’s very obvious in every action Squidward carries out. He rarely dates and when he does there is never a second date. He is a healthy man of his age. He really doesn’t have many friends. There is his two neighbors Spongebob Squarepants and Patrick Star, they want to be friends with him but Squidward can barely tolerate either of them. When he is sad he usually turns to his music, painting, or bubble baths which he takes very often. His life goal or aspiration is to be a famous artist and musician. He’s a very smart individual but has absolutely horrible social skills.
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
If someone is a native of Maryland, they know exactly what one is talking about when the Maryland Blue Crab is brought up into a discussion. In 1989, the Maryland Blue Crab, scientifically known as the Callinectes sapidus Rathbun, was designated the State Crustacean (Blue Crab, Maryland State Crustacean). This crab is not only a key component on the ecological system of the Chesapeake Bay, but also a key economical component of commercial fisheries; although not endangered, the issue of maintaining the population of the species is critical to the Chesapeake Bay and also its inhabitants.
I learned that the phylum Annelids can consist of many creatures such as earthworms, leeches, and scale worms can adapt to a variety of environments. Annelids’ bodies are divided into segments which are seen as rings by the naked eye. They have muscles which help them move by contracting their longitudinal and circular muscles. When Annelids take in food, the food particles travel through one end of the body and are excreted out the other side. The video enhanced my understanding about Annelids because without seeing different species and what classified them as Annelids I would have never known an earthworm or a leech fell into that phylum.
Crustaceans belong to the Arthropoda Phylum, which includes critters like ants, spiders, and centipedes. I know! Crazy to think that a delicious crab is in the same group as a spider! But they share similar characteristics. For starters, members of the Arthropoda Phylum do not have a backbone like you and me, so they are called __invertebrates__. And, as mentioned earlier, their skeleton is external, which is referred to as an __exoskeleton__.
In some cases the eggs will get flushed out of the host. When this happens it releases miracidia that penetrate in to the snail. The snail is the intermediate host. When in the snail the organism uses asexual reproduction then development of cercariae. The cercariae can survive in...
Liubicich, D.M., et al. 2009. Knockdown of Parhyale Ultrabithorax recapitulates evolutionary changes in crustacean appendage morphology. PNAS 106 (33): 13892-13896
Parasites and their Virulence Why do some parasites kill the host they depend upon while others coexist with their host? Two prime factors determine parasitic virulence: the manner in which the parasite is transmitted, and the evolutionary history of the parasite and its host. Parasites which have colonized a new host species tend to be more virulent than parasites which have coevolved with their hosts. Parasites which are transmitted horizontally tend to be more virulent than those transmitted vertically. It has been assumed that parasite-host interactions inevitably evolve toward lower virulence.
to the lobster and crab. Their closest living relative today is the horseshoe crab.The name
Arthropods account for 80 percent of all animal species. Because arthropods have so many amazing features, they are very important animals. They have an exoskeleton, and an open circulatory system. Every time you look at an arthropod you will see a segmented body. Arthropods are astounding creatures! Without them our food chain would be all over the place!
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
Arthropods are animals belonging to the phylum Arthropoda, which is the largest of all phyla in the Animal Kingdom, with more than one million species, making them almost 80% of the whole kingdom. These include insects, arachnids, crustaceans and many more, most of which are quite small, the biggest being the Japanese Spider Crab with a leg span of 3.5 meters and the smallest being the microscopic Plankton.
Porifera is the most simplistic phylum under the kingdom Animalia. The sponges have no tissue layers, but instead an interior and exterior layer with a gelatinous middle layer that separates the two. They are the only phylum with asymmetrical symmetry. Throughout the advancing phyla it will be shown this trait is lost. Porifera lacks a proper digestive system, but a canal system allows the sponges to filter feed. Along the inside of a sponge, flagella pump water through the sponge’s body. This process brings in oxygen and other small organisms and then flows out the top of the sponge, the osculum, removing waste by diffusion. Sponges lack a circulatory system, as does many of the first couple of phyla. A coinciding factor could be their small size. A nervous system is also missing, but very basic nerve cells within the pores sense the water currents. Gas exchange occurs through these pores. Reproduction in sponges can be asexual by budding, gammation, or fragmentation. Some sponges can also have sexual reproduction occur as an egg gets released and fertilized in the open water by free floating sperm. After this stage they cling onto rock and begin their sessile, basic, life....