Final Exam Study GuidePHYLUM ARTHOPODA IISubphyla: Myriapoda HexapodaClass: Chilopda (centipedes)Diplopoda (millipedes)InsectaSubclass ApterygotaPterygota (2 divisions)Divisions/Orders 1.Exopterygota (hemimetabolous): Odonata, Orthoptera, Isoptera, Hemiptera,Homoptera2. Endopterygota ( holometabolous): Coleoptera, Lepidoptera, Diptera, Hymenoptera General CharacteristicsSymmetry:-Bilateral-Uniramous: appendages are unbranched (so just one branch), 1 pair of antennae, mandibles (“jaws”) present, 2 pairs of maxillae (usually), body is covered with a (waxy) cuticular exoskeletonCirculatory System: open circulatory system consisting of a hemocoel filled with hemolymph (blood); thehemoceol is a remnant of the blastocoel; this is the main body-cavity in arthropods – the true coelom is reduced to small areas housing gonads & sometimes excretory organs; blood empties into sinuses to bathe organs and tissues and returns directly from the hemocoel to the heart through ostia Gas Exchange: tracheal tubes open to the outside by (valved) spiracles ;if juveniles are aquatic, they may have gillsDigestive System: -complete with regionalized specialization-foregut, midgut (absorption of nutrients), hindgut-inner cuticle lining (gets molting as well)Excretion: -malpighian tubules =allows insects to conserve H2O & withstand terrestrial environments; atend of hindgut insects resorb water along with K+ & Na+ ions Reproduction: -separate sexes, usually internal fertilization (terrestrial), few show maternal care, sexualcannibalism in someMuscular System: -direct flight muscles=pull the wings down-indirect flight muscles= contact to pull body wall down & wings get uplifted “by default”; when relaxedbody wall moves up and wings move down-some insects have both (e.g. Orthoptera, Odonata) or ONLY indirect muscles (Diptera,Hymenoptera) CLASS CHILOPODA (Centipedes)Characteristics: -active predators- Dorsoventrally flattened body with 2 Tagmata: Head and trunk- 1 pair of appendages per segment- Some have poison claws CLASS DIPLOPODA (Millipedes)Characteristics: - herbivores/detritivores- 2 Tagmata with cylindrical bodies; 2 pairs of append per somite- 2 pairs of spiracles per somite- Some secrete defensive toxic fluids from special glands= hydrogen cyanide CLASS INSECTA General Characteristics: - primarily terrestrial- Conserve H2O by: waxy waterproof cuticle, valved spiracles, malpighian tubules (conserveh2O)- Organization : 3 Tagmatao Head: 6 segments, 1 pair of antennaeo Thorax: 3 segments, 2 legs/segment (3 pairs total)o Abdomen: 11 segments- Embryonic Develop : Eucoelomates, protostomes where blastopore= moutho Schizocoelous; spiral cleavage; det. cell fate- Skeleton/Support : Exoskeleton, Bilateral Symm.- Movement/Locomotion : jointed appendages and muscleso Apodeme= site of muscle attachment onto exoskeletono Flight= wings, usually 2 pairs and diff types: 1. Membranous (Hymenoptera)2. Plated (Coleoptera)3. Scaly (Lepidoptera)4. Balance organ (Diptera=halteres)- Sensory/Nervous : Ventral nerve cord w/ ganglia; Compound eyes; tympanic membranes=sense vibrations- Digestion Feeding (complete) : 3 gutso Foregut: lined with cuticle; derived frm ectoderm1. Located in head region2. Mechanical processing (protoventriculus) and gastric mill3. Mouth parts highly modified= mandible, maxillae, labia- Excretion/Osmoregulation/Circulation = Malpighian tubules and open circulation- Respiration: Tracheal system w/ spiracles in body wall- Reproduction: Dioecious with internal fertilizationo Spermatophore (sperm pkts of male) & spermatatheca (female storage)o Elaborate Courtshipo Metamoprhosis: Transfromation of growing, non-reproducing immature stateto non-growing reprod adult state1. Ametabolous = no metamorphosis (no wings), primitive (e.g. silverfish)2. Hemimetabolous = incomplete metamorphosis, mini adult stage (nymph),wings develop as little buds, eggnymphadult3. Holometabolous = complete metamorphosis; middle stage looks NOTHINGlike adult, wings develop on INSIDE, egglarvaepupaadulto Diapause= state of dormancy in response to environmental cues; hibernationsduring winter and aestivation during summer Subclass: Apterygota (ametabolous and wingless) Subclass: Pterygota= Exopterygota & Endopterygota- Exopterygota= wings develop inside; hemimetabolous5 Orders :1. Odonata: large membranous wings (e.g. damsel/dragon- flies)2. Orthoptera: Chewing mouthparts (e.g. grasshoppers, crickets, roaches, mantids)3. Isoptera: most stages no wings; complex social organization (e.g. termites)4. Hemiptera: True Bugs form “X” on back, predacious (e.g. bedbugs, assassin bugs,stink bugs)5. Homoptera: Wings make “home” over back; ALL are phytophagus=suck plant juices;(e.g. cicadas, aphids, leafhoppers)- Endopterygota= Wings develop outside4 Orders:1. Coleoptera: largest order in the world; front wings have a plated aromor covering=elytra; (e.g. beetles, fireflies, weevils, grubs)2. Lepidoptera: Scaly wings; Butterflies= smooth antennae & moths= fuzzy antennae3. Diptera: True flies. One set of flying wings and second set for balance= halters4. Hymenoptera: biting mandibles and venomous. (e.g. ants, wasps, bees)Why So Diverse?: -due to body plan capable of great modification= adaptive radiation (e.g flight=disperse to new habitats, better food sources, escape bad situations)• small size (can exploit more niches)• short generation time (recall natural selection criteria)• metamorphosis (use > 1 niche; life stages don’t compete!)• winged adults (dispersal)• adaptations to terrestrial environments (e.g. waterproof cuticle, tracheal system, etc.)• sophisticated sensory system • sophisticated behavior and communication• co-evolutionary interactions with other organisms (e.g. plant mutualisms and parasitism)Insect Ecology: - insects are important pollinators- many flowering plants have co-evolved with their specific insect pollinators- some develop “rewards” top attract pollinators (e.g. extra floral nectarines attract ants) and“displays” to advertise these rewards (e.g. nectar guides)- Eusocial insects (hymenoptera/isoptera) live in societies char. by: cooperative care of young,overlapping generations, polymorphism o caste sys. Queen / male reproductives (fertile), workers/soldiers (sterile)o Altruism by giving up reprod & caring for another’s offspring= KIN THEORYo
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