Introduc)on*to*Arthropods*Arthropod*Classifica)on:*Five*subphyla*1.*Trilobitomorpha* 3.*Cheliceriformes*2.*Crustacea*5.*Hexapoda*4.*Myriapoda*Evolu)on*of*Insects:*150*MYA*Major*insect*groups**are*in*place**Appr.*400*mya*Insects*arose*Cambrian explosion (530 mya): the origin of the first arthropods Arthopods first appear in fossil record approx 530 mya.Rela)ve*diversity*of*arthropods*Total*number*of*species*described:*1,581,000**Total*number*of*arthropods*described:*1,048,000**Total*number*of**insects*described:*925,000***How*many*species*are*there ? **Es)mates*range*from*3,000,000Q30,000,000*total*species****Q>2,000,000*–*20,000,000*insect*species*Es)mate:*200*million*individual*insects*for*each*hum an**on*the*planet!*Insect*diversity*“an*inordinate*fondness*for*beetles”*Why*so*many*species*of*insects?*Insects*are*a*very*old*group*Q>*lots*of*)me*to*diversify**Insects*are*small*à*Exploit*large*numbers*of*habitats****Phytophagy*is*associated*with*increased*diversifica)on*rates**Q>*specializa)on*on*specific*plants*to*be*able*to*deal*******with*plant’s*defenses.**The*most*speciesQrich*groups*have*complete*metamorphosis**Q>*allows*different*specializa)on*between*larval*and*******adult*stage**Most*insects*can*fly*Q>*enhances*dispersal**Another*successful*innova)on*is*wing*folding*(e.g.*Beetles)*Arthropod*Classifica)on:*Five*subphyla*1.*Trilobitomorpha* 3.*Cheliceriformes*2.*Crustacea*5.*Hexapoda*4.*Myriapoda*Crustacea*(52,000*species*described)*10,000,000*tons*consumed*by*humans*in*2005*Copepod*Daphnia*Parasi)c*isopod*barnacles*Isopod*(woodlice)*Some examplesCoconut*crab*Lobster*Crustacea*Cont’d*Mantis shrimpCheliceriformes*Class*Chelicerata**subclass*Merostoma***order*Eurypterida****(Water * scorpions)***order*Xiphosura*******(Horse shoe *crabs)**subclass*Arachnida***order*Scorpiones****order*Uropygi***order*Amblypygi***order*Araneae*(Spiders)***order*Opiliones***order*Acari*()cks*and*mites)***order*Solpugidae**Class*Pygnogonida*(Sea*spiders)*Cheliceriformes*Class*Chelicerata**subclass*Merostoma***order*Eurypterida****(Water * scorpions)***order*Xiphosura*******(Horse shoe *crabs)**subclass*Arachnida***order*Scorpiones****order*Uropygi***order*Amblypygi***order*Araneae*(Spiders)***order*Opiliones***order*Acari*()cks*and*mites)***order*Solpugidae**Class*Pygnogonida*(Sea*spiders)*Cheliceriformes*Order*Eurypterida**(Water*scorpions)*Order*Xiphosura*(Horse*shoe*crabs)**Cheliceriformes*Order*Scorpiones**Order*Uropygi*(vinegaroons)*Cheliceriformes*Order*Amblypygi*Order*Araneae*(Spiders)*Cheliceriformes*Order*Opiliones*(Harvestmen)*Order*Solpugida*Urban Myth Camel Spider (Solpugida)Cheliceriformes*Order*Acari*()cks*and*mites)*Arthropod*Classifica)on:*Five*subphyla*1.*Trilobitomorpha* 3.*Cheliceriformes*2.*Crustacea*5.*Hexapoda*4.*Myriapoda*Subphylum**Myriapoda*Class*Diplopoda **(Millipedes)*Class*Chilopoda*(Cen)pedes)*Class*Pauropoda* Class*Symphyla*Arthropod*Classifica)on:*Five*subphyla*1.*Trilobitomorpha* 3.*Cheliceriformes*2.*Crustacea*5.*Hexapoda*4.*Myriapoda*Subphylum*Hexapoda*Class*Parainsecta*Class*Entognatha*Diplura*Class*Insecta*Protura*Collembola*Class*Insecta*Apterygota:*(wingless)*Pterygota:**(winged)*Paleoptera:*Neoptera:*Silverfish********Bristletails*Mayflies*Dragonflies*Damselflies*Endopterygota**(Holometabolous)*Exopterygota**(Hemimetabolous)*Complete*Metamorphosis*Incomplete**Metamorphosis*Exopterygota:* Endopterygota:*Wings*develop*externally* Wings*develop*internally*Juvenile*(nymph)*and*adult*look**similar*Juvenile*(larvae)*and*adult**very*different*Pupal*stage*Exopterygota:*Endopterygota:*Major*Orders:* Major*Orders:*Bugerflies*Flies/Mosquitoes*Lacewings/Antlions*Dobsonflies*Scorpionflies*Beetles*Wasp/Bees/Ants*Fleas*Caddisflies*Bi)ng/Sucking*Lice*****True*Bugs/Cicadas **Thrips * **Praying*Man)s * **Cockroaches **Termites*S)ck*insects*Grasshoppers*Earwigs*Webspinners*Stoneflies*******Some*exopterygotes:*A B C DSome*Endopterygotes:*A B C D ESome*Endopterygotes*Cont’d:*A B CSome*Endopterygotes*Cont’d:*A B CEO Wilson: “insects and other land dwelling arthropods are so important that if all were to disappear, humanity could not last more than a few months. Most of the amphibians, reptiles, birds and mammals, would crash to extinction at the same time. Next to go would be the flowering plants, and with them most of the physical structure of the forests and other terrestrial habitats of the world. The land surface would literally rot. As dead vegetation piled up and dried out, closing the channels for nutrient cycling, other complex forms of vegetation would die off as would all but few land vertebrates. The free-living fungi would increase enormously at first, but then most species would perish. The land would look like early Paleozoic times, covered by patches of wind pollinated vegetation, small bushes and trees here and there, and largely devoid of animal life”. Importance of arthropodsRoles in ecosystem: 1 Nutrient recycling of leaf litter, wood, carrion, dung, soil turnover. 2 Plant propagations 3 Maintenance of plant community structure through phytophagy 4 Sources of food for animals 5 Maintenance of animal community structure -> predation, parasitism Importance of arthropodsImportance of arthropods Other ways in which arthropods are beneficial (to humans): 1 Food (Crustaceans, some insects, spiders) 2 Pollinators of human crops 3 Products; honey, silk (4 Great subjects for biologists)Importance of arthropods Ways in which arthropods are damaging: Damage crops directly Transmit plant viruses Destroy products in storage (particularly grains) Damage wooded structures ($5 billion cost in US)Gypsy Moth Brought to the US in 1868, to breed hardier silk worm 450 species of plants are its food $500 million spent on controlHuman health and disease: Malaria: 630,000 deaths /250,000,000 cases/ 3.3 billion at risk Yellow fever: 30,000 deaths/ 200,000 cases Dengue fever: 80,000,000 infections yearly (25,000 deaths) Sleeping Sickness: 300,000-500,000 cases (if untreated 100% mortality) Visceral Leishmaniasis: 500,000 new cases (mortality rate 75-95% if untreated). River Blindness: 42,000,000 infected 600,000 blind Chagas: 8,000,000 cases Plague: 1340’s 75,000,000 deaths West Nile: 2,873 cases of encephalitis, 286 deaths (2012)3 The Arthropod Body Plan Exoskeleton Molting