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Arthropods. Arthropods. The phylum Arthropoda makes up over 75% of the world’s species. Arthropods include insects, centipedes, millipedes, spiders, ticks, scorpions, mites, lobsters, shrimps, crabs, and crayfishes. Arthropods.
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Arthropods • The phylum Arthropoda makes up over 75% of the world’s species. • Arthropods include insects, centipedes, millipedes, spiders, ticks, scorpions, mites, lobsters, shrimps, crabs, and crayfishes.
Arthropods • A typical arthropod is an invertebrate animals with bilateral symmetry, an exoskeleton, and joint structures called appendages. • An appendage is any structure, such as a leg or antenna, that grows out of the body of an animal. • In arthropods, appendages are adapted for a variety of purposes, including sensing, walking, feeding and mating. • Joint appendages are useful because they allow for more powerful movements during locomotion, and they enable the appendage to be used in many different ways.
Body Structure • The body of arthropods is made up of three segments: • Head • Thorax • Abdomen
Desert Tarantula Japanese Beetle Exoskeleton • The success of arthropods as a group can be attributed in part to the presence of an exoskeleton. • The exoskeleton is a hard, thick, outer covering made of protein and chitin. • In some species, the exoskeleton is a continuous covering over most of the body. Example: Beetle • In other species, the exoskeleton is made of separate plates held together by hinges. Example: Spider • What are some advantages and disadvantages to having and exoskeleton?
Molting • While the exoskeleton provides protection, one disadvantage is that the exoskeleton cannot grow with the animal. • Therefore, arthropods must go through a process called molting, where they shed their exoskeleton and grow a new one. • What are advantages and disadvantages to molting? Cicada molting
Arthropod Behaviors Black Widow Spider • Female is black with a red, hourglass-shaped spot on her underside. • After mating, female eats the male.
Arthropod Behaviors Praying Mantis • Female praying mantises eat males. Therefore, males have to “sneak up” on females in order to mate. • Males also perform a mating dance so females know not to eat them.
Social Insects • Bees, ants, wasps and termites are known as social insects because they form elaborate and complex social systems which rely on communication and social interaction. Bees Ants Wasps Termites
Bees • Bees demonstrate a hierarchical system (Caste System) • Queen Bee – The boss. She lays all of the eggs. • Worker Bees – Only females. Perform daily functions of hive (honey, wax, building) • Drone Bees – Only males. Tend to Queen and fertilize eggs. Queen Bee
Bees • Bees communicate through dance. • Upon returning from a rich nectar source, a worker bee will perform one of two dances, a “round dance” or a “waggle dance,” in order to tell the other bees where to find more nectar. • A “round dance” indicates that nectar is nearby, but gives no direction. • A “waggle dance” indicates that nectar is far away and provides a direction for the bees to follow. “Round dance” “Waggle dance”