Transcript Three pairs
Spiders, insects, centipedes, scorpions, shrimp, crabs, lobsters, butterflies •Jointed appendages The world arthropod population has been estimated at a billion billion CLIP Major Characteristics: •Segmented bodies covered in an exoskeleton of chitin (Carbohydrate). •Protosome coelomate •Three segments: •Head, Thorax, Abdomen Chitin • Strong but flexible • Nitrogenous polysaccharide. Exoskeleton Protection helps prevent water loss provides framework for muscle attachment Does not grow. When the organism outgrows it, it molts. oGland digest inside of old exoskeleton and then other glands secrete a new skeleton. oWhen new one is ready, organism pulls out of the old. Have more sensory apparatus than the annelids gives them more speed and freedom of movement Groups of segments and their appendages have become specialized for a variety of functions, permitting efficient division of labor among regions. Nervous System Arthropods have a well-developed nervous system. •A brain is connected to a pair of ventral nerve cords with several segmental ganglia. Nervous System – Chords meet in the head, where the ganglia from several anterior segments are fused into a cerebral ganglion (brain). – Close to the antennae, eyes, and other sense organs concentrated on the head. • Grasshopper: Digestion – Long tube containing crop & gizzard – Specialilzed mouth parts for tasting, biting & crushing Reproduction •Metamorphosis. •Process of changing shape and form. Two types: Complete •Larvae look completely different from adult Incomplete •Larvae look like a small adult- lack sex organs Metamorphosis is central to insect development. – Larval stages specialized for eating and growing change morphology completely during the pupal stage and emerge as adults. Respiration: •Most have tracheal tubes that extend throughout the body. Air enters through spiracles. •Spiders- book lungs/gills. Tracheal tubes- respiration Complex mouth parts Three parts specialized for diet chitin-lined tracheal system carries O2 from the spiracles directly to the cells. Respiration: Circulation Well developed heart with arteries and vessels oOpen circulatory system in which hemolymph fluid is propelled by a heart through short arteries into sinuses (the hemocoel) surrounding tissues & organs. oHemolymph returns to the heart through valved pores. Hemocoel- internal cavity which bathes tissues w/an O2 & nutrient carrying fluid called hemolymph Open systems are also seen in mollusks In an open circulatory system, blood leaves the blood and flows freely within the tissues. This system is not very efficient because there is no blood pressure to move blood rapidly through the tissues. The oval line in the diagram below represents an animals body. Removal of waste Malpighian tubules (outpockets of the digestive tract) Aquatic – Tubules excrete directly into water clip Major Groups: Classified based on number and structure of body segments.4 subphylum, 10 classes All extinct Were marine arthropods about 500 million years ago. Became extinct 200 million years ago. •Lobster, crab, shrimp, Crayfish, Barnacles •4 classes •Mainly aquatic (Marine and freshwater) •Terrestrial -Pill bugs • 2 or 3 body segments • Head-compound eyes • 2 pairs of branched antennas • Chewing mouth parts-mandibles 2 major body parts 1.Cephalothorax -Fusion of head w/thorax -Covered by a carpace. 2. Abdomen name is derived from the crusty exoskeleton • Head usually bears compound eyes and five pairs of appendages • a. First two are antennae and antennules; in front of the mouth, they have sensory functions. • b. Three pairs (mandibles, first and second maxillae) lie behind mouth and are used in feeding. “Spiders and their relatives” 3 classes •Have two mouth parts: •Cheliceras-fangs-stab and paralyze •Pedipalps- to grab prey •Two body segments •Cephalothorax and abdomen •Almost all have four pairs of walking legs •Book lungs or book gills Lycosid spider: female with offspring Spiders, scorpions, mites, ticks Spiders Book Lungs Inject digestive enzymes into prey All spiders produce silk- may not make webs Spin webs by forcing liquid silk through their spinnerets Mites and Ticks Usually parasitic Mouth parts, usually needlelike, are used to dig into host tissue and suck blood. Ticks- Transmit bacteria that causes Lyme Disease & Rocky mountain spotted fever Mites- chiggers can cause itching and painful rashes in humans. “Insects and their relatives” Beetles, Flies, Butterflies, Ants, Grasshoppers, Fleas, Crickets, Mosquitoes, bees •Three body regions •Head, thorax, abdomen •Three pairs of legs attached to thorax. Jumping, walking or capturing prey. •Pair of antennae for sensing the environment • Pair of compound eyes on head •Two pairs of wings (chitin) on thorax •Flying-wider variety habitats clip Insect Eyes DOWNS •Termites destroy wood •Moths eat cloth •Locusts destroy crops •Cotton Boll Weevils •Mosquitoes and diseases UPS •Bees, butterflies, etc., pollinate crops •Some produce silk, wax, honey •Food Insects and communication Sounds- chirps, buzz Light- Male fireflies Chemicals- Pheromones (mate, danger, or alert) Clip Insect Societies •Complex group that works together for the good of the colony. •Different roles are preformed by groups called castes. •Each castes has a different body form to carry out their specific task. •Very sophisticated communication. Carpenter ant castes, from left to right: queen, winged male, major worker, minor worker •Bees Dance! •Ants leave pheromone trails. “Dances With Bees” ROUND DANCE-used when the source of food (nectar or pollen) is less than 100 metres away WAGGLE DANCE Animation Millipedes •Each body segment has two pairs of legs •Detritivores- live under rocks and in decaying logs •Some can secret unpleasant or toxic chemicals for defense. slow-moving vegetarians scavengers Centipedes •Each body segment has one pair of legs •Carnivores •Mouth parts contain venomous claws •Live under rocks or in the soil •Must live in moist environments because their spiracles cannot close and they lack a waterproof coating. move rapidly and prey mostly on small invertebrates. Anthropods feed on All types of foods respire using reproduce using Internal fertilization have well-developed External fertilization Tracheal Heart Book lungs tubes Book gills Brain Muscles