Crustaceans like crayfish, lobsters, and crabs are all arthropods. They have remote nipples, that are used for warmth. The general consensus among evolutionists is that fish evolved from segmented worms. Why is panda classified as an animal? Crab, shrimp, and lobsters are in the same phylum as crayfish. They are all in the arthropoda phylum. Arthopods have an exoskeleton, a segmented body, and jointed appendages.
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Q: Why it is the crayfish is classified as a segmented animal? Write your answer Related questions. Why is a crayfish classified as a segmented animal?
Why is the crayfish classified as a segmented animal? Arthropod segments have also fused together into functional units called tagma.
This process of segment fusion, or tagmosis , usually results in an arthropod body that consists of three major sections, a head, thorax, and abdomen. Sometimes the head and thorax are fused together into a cephalothorax. Each of these body sections still bear the appendages that went with it, though these appendages are often highly modified. Arthropods are very highly cephalized, often with intricate mouthparts and elaborate sensory organs, including statocysts , antennae, simple eyes and compound eyes.
Sensitive hairs on the surface of the body can detect touch, water currents, or chemicals. Their nervous systems are highly developed, with chains of ganglia serving various parts of the body, and three fused pairs of cerebral ganglia forming a brain.
Aquatic arthropods respire with gills. Terrestrial forms rely on diffusion through tiny tubes called trachea. Trachea are cuticle-lined air ducts that branch throughout the body, and open in tiny holes called spiracles , located along the abdomen. Insects can open and close these spiracles, to conserve water that would otherwise be lost to evaporation from the open tubes.
Their reliance on diffusion for respiration is one of the reasons that insects are small. Arthropods excrete by means of malphigian tubules , projections of the digestive tract that help conserve water. Terrestrial forms excrete nitrogen as uric acid , as do birds.
Their waste is nearly dry, a superb adaptation to life on land. Arthropods have an open circulatory system, and separate sexes. Fertilization is usually internal, another adaptation for terrestrial life. Males and females often show pronounced sexual dimorphism.
Order Orthoptera - grasshoppers, crickets, roaches. In chelicerates, the first pair of appendages are called chelicerae, and are modified to manipulate food. They are often modified as fangs or pincers. Chelicerates lack antennae. Horseshoe crabs have larvae that are very similar to trilobites, and they may be descendants of this long vanished group.
Horseshoe crabs are nocturnal, feeding on annelids and molluscs. They swim on their backs, or walk upright on five pairs of walking legs.
They live in the deep ocean, migrating inshore in large numbers in the spring to mate on the beaches during moonlight and high tide - much like undergraduates on Spring Break. This very successful group of arthropods have four pair of walking legs 8 legs. The first pair of appendages are the chelicerae , and the second pair are pedipalps , appendages modified for sensory functions or for manipulating prey. They are mostly carnivorous many mites are herbivores.
Most secrete powerful digestive enzymes which are injected into the prey to liquify it. Once dissolved in its own epidermis, the prey is sipped like a root beer float. Order Scorpiones 2, sp. Scorpions date back to the Silurian, about mya, and may be the first terrestrial arthropods. Order Araneae 32, sp. Not all spiders spin webs.
Wolf spiders are the tigers of the leaf litter, and the common jumping spider leaps several times its body length to catch its prey. Spiders use pedipalps as copulatory organs. Spiders breathe by book lungs. Order Acari - 30, sp.
Most are very tiny, less than 1 mm long. The thorax and head are fused into a single unit cephalothorax. Order Opiliones 5, sp. It has an oval body with extremely long legs, which they frequently lose in various accidents and brushes with predators. They are predators, herbivores, and scavengers. Look at them closely next time you see one.
They carry their eyes atop a little tower on their back weird! Crustaceans are mostly marine, and dominate the ocean to the same degree that insects dominate the land and air. Despite their aquatic diversity, there are very few terrestrial crustaceans, just as there are very few truly aquatic insects. Crustaceans have biramous appendages. Each leg has an additional process, like a little miniature leg branching off from the main leg. Many groups of crustaceans have lost this extra appendage during subsequent evolution.
The Order Decapoda have five pair of walking legs, and include the familiar crabs, lobsters, and crayfish. The first pair of appendages are usually modified as antennae. Crustaceans have two pair of antennae. Another set of anterior appendages are modified as mandibles, which function in grasping, biting, and chewing food. Male crayfish also use one pair of legs as a copulatory organ.
All crustaceans share a common type of larva called a nauplius larva. They are one of the few successful terrestrial crustaceans.
They feed on decaying vegetation in the leaf litter. Uniramians have a single pair of antennae, and uniramous appendages. They probably evolved from oligochaete worms. Class Chilopoda - 2, sp. Centipedes dwell in damp places under old logs and stones. Study now. See Answer. Best Answer. Because Its body structure has segments. Study guides. Q: Why is the crayfish clasifed as a segmented animal? Write your answer Related questions.
Why is a crayfish classified as a segmented animal? Why is the crayfish classified as a segmented animal? Why are crayfish arthropods? Why is the crayfish classified as a segment animal? Why it is the crayfish is classified as a segmented animal? Why is a crayfish classified as a segmented animal if it has an inflexible cephalothorax? Why is a crayfish considered an arthropod? Are crayfish a arthropods? Why is the crayfish's body segmented?
What is it clasifed as? What two characteristics make a crayfish and arthropod? Which body region of the crayfish is most obviously segmented? Why do the crayfish belong to arthropoda? What animal evolved from segmented worms? Name two other animals in the same phylum as a crayfish? Are crayfish a group animal?
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