Crayfish Case Essay Sample
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Crayfish Case Essay Sample
The crayfish falls within the kingdom – anamalia, phylum – Arthropoda, Class – Crustacea, Order -Decapoda , and family – Cambaridae.
Crayfish like to be where it’s dark and cool, and during much of the daylight they will be found by them selves, under a rock or vegetation, waiting for dark, when they come out to forage for food. This is highly variable, ranging from deep holes to sluggish streams. A suitable habitat is medium-sized streams containing riffles and rocky pools. They burrow very aggressively, burrowing to find warmth, moisture, and food or just to pass the time. In Arizona we are trying to rid of crayfish because they aren’t native here and are taking over fish population.
Prey & Predator
Crayfish are omnivorous, which is to eat just about anything they can find or catch either dead or alive. Large food is held and torn to pieces in the large pincers and conveyed to the mouth by the smaller specialized legs near the head. That’s what crayfish do most of the time, loaf all day and look for food all night. Crayfish are an important link in the food chain of the aquatic community. They feed on living animals and plants, and also consume a fair amount of dead plants, dead or dying animals, and detritus. There is also a large number of species of other animals known to eat crayfish. Crayfish have been reported to be preyed upon by at least 46 species of fish, 10 amphibians, 20 reptiles, 38 birds, and 6 mammals (including humans). Crayfish are preyed upon heavily by fish, such as trout, pickerel, and bass, and other invertebrates may eat them.
Crayfish have bodies similar to that of the presumed ancestral crustacean. Such a body is essentially shrimp-like in that it is elongate and nearly cylindrical in cross section. The abdomen is well developed and its segmentation is easily noted. The crayfish has bilateral symmetry, anterior, posterior, dorsal, ventral, right, and left.
The crayfish nervous system is composed of a ventral nerve cord fused with segmental ganglia, and the supresophageal and subesophageal ganglia. Giant neurons in the ventral nerve cord function in escape responses. The supraesophageal and subesophageal ganglia control the head appendages in response to sensory input received from receptors. Receptors are organs that receive senses and pass these to the brain. Examples are the eyes, antennas, and ears. The tactile recoptors are widley distributed on appendages and joint as they function as equilibrium, balance, and position senses.
There is a dorsal tubular heart and several arteries. The crayfish has an open circulatory system in which the blood flows from arteries into sinuses, or spaces, in tissues. The blood flows over the gills before returning to the heart.
The maxillae pass the pieces of food into the mouth. The food travels down the short esophagus into the stomach. The digestive gland produces digestive substances and from which the absorption of nutrients occurs. The green glands (also called antennal glands because they have ducts which exit near the base of the second antennae) function in excretion and osmoregulation. Undigested material passes into the intestine. The intestine is attached to the lobed stomach. The undigested material is exiled from the anus.
The gills are feather-like structures found underneath the carapace and
attached to the chelipeds and walking legs. There is a constant flow of blood to the gills releases carbon dioxide and picks up oxygen.