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Arthropods are animals belonging to the phylum Arthropoda. They are invertebrates, and they have an exoskeleton, jointed appendages, and a segmented body.〔''Merriam-Webster'', "()", accessed 8 Dec. 2010.〕 Some common examples of arthropods are arachnids and insects. Arthropods are used in film either to create fear and disgust in horror/thriller movies, or they are anthropomorphized and used as the characters in animated children's movies. ==Arthropods== (詳細はAnts, spiders, shrimp, crabs and bees are all arthropods. This huge array of diversity is vital to the animal kingdom. Almost every organism on the earth interacts in some way with arthropods. The first ancestor of the arthropods was alive some 555 million years ago. It was likely a sediment feeder, with armored plates and biramous limbs. Over the course of 555 million years, this creature evolved into several different subphyla. One of these subphyla is Trilobitomorpha, which contains trilobites, an extinct race. Chelicerata, another subphyla, contains arachnids and scorpions. Myriapoda contains millipedes and centipedes, Hexapoda contains insects, and Crustacea includes lobsters, crabs, and shrimp. In order for an animal to be classified as an arthropod, it must have several distinct characteristics. It must be an invertebrate, which means it does not have a backbone or notochord. It must have an exoskeleton, usually made of chitin, a tough material formed from sugars that is also found in the cell walls of fungi.〔Thiers, Genevieve, ''essortment,'' 2002, "()", 8 Dec. 2010.〕 It must have jointed appendages, with a definite separation of tissue in the joints, rather than a continuous tentacle. It must have a segmented body, although the precise number of segments varies from arthropod to arthropod—insects have three segments, head, thorax, and abdomen, while an arachnid has just two, the cephalothorax and abdomen. Insects are some of the most diverse animals on the planet, with an estimated six to ten million species. Insects come in all shapes and sizes, from the sizable Goliath Beetle to the microscopic fairyfly. Some insects, like beetles, are scavengers. Some, such as bees, get their sustenance from the nectar of plants Some insects, like mosquitoes, ticks, and fleas, suck the blood of humans and other mammals. Insects live in almost every climate, all over the world. Arachnids are slightly less diverse than insects, coming in at just over 100,000 named species. All arachnids have 8 legs, although for some arachnids one pair of legs serves a sensory function rather than a locomotive one. The most common types of arachnids are spiders and scorpions. Arachnids, too, are found all over the world. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Arthropods in film」の詳細全文を読む スポンサード リンク
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