Veena+-+Crustacean

Crustacean: "the insect of the sea"  **Kingdom: **Animalia **Phylum:** Arthropoda  **Class:** Crustacean
 * Body Plan:** Crustaceans usually have bodies that are divided up into three parts; the head (cephalon), the thorax, and the abdomen. Each segment usually has appendages such as antennae, legs, and various types of feet. These parts are protected by a carapace, or the outermost shell of the exoskeleton.[[image:crustacean-body-structure.jpg width="416" height="265" align="right"]] **Germ Layers:** Triploblastic which means that endoderm, mesoderm, and ectoderm are all present.
 * Symmetry:** Bilateral symmetry present
 * Coelomate:** Coelom present


 * Habitat:** Most crustaceans live in marine or freshwater environments but some have adapted over time and live on land.
 * Movement:** Most have legs that are able to swim or walk
 * Skeletal System:** Exoskeleton present

**Special Adaptations:** Include two specialized types of feet, pereiopods (walking) and maxillipeds (feeding). **Feeding Patterns:** There are three main types of crustacean feeding; scavenging, filter feeding and parasitism. In scavenging, the crustacean use its feeding legs to pick up food particles and other small species. In filter feeding, the species uses fine combs on appendages on its thorax segment to collect particles. In parasitism, the species removes and digests its own parasites. **Respiration:** They use highly specialized gills that permit gas exchange when in contact with water. For land crustaceans, respiration occurs in the trachea with the help of small tubes that connect internal tissues with the surface of the body. **Circulation:** Open system, includes a heart. **Excretory:** Specialized organs called green glands that collect residuals and wastes from around the body and release them from pores underneath the antennae. **Nervous System:** Includes advanced sensory receptors and cephalization. In the front of the body, the brain (formed by nerve cell bodies) connects with two ventral chains that run throughout the body to coordinate motor and sensory nerves. **Reproduction:** Most reproduce sexually, though some reproduce asexually. Sex changes during crustacean lifetimes are not uncommon. **Sources:** [] [] [] [|http://www.britannica.com/EBchecked/topic/144848/crustacean/33799/Natural-history#] []
 * Evolutionary Advancement:** Crustaceans were one of the firsts to develop eyes with photoreceptors, allowing them to see better in darkness. Limbs have grown to be jointed, allowing for more efficient movement. Filter feeding methods have also evolved.

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