Arthropoda Classification Phylum Arthropoda Subphylum Uniramia- (terrrestrial mandibulates) Class Chilopoda- centipedes Class Diplopoda- millipedes Class Insecta- insects Subphylum Crustacea- (aquatic mandibulates) lobsters, crabs, crayfish, shrimp, sow bugs (pill bugs), krill and barnacles Subphylum Chelicerata Class Arachnida- spiders, scorpions, ticks, and mites Class Merostomata- horshoe crab Class Pycnogonida- sea spiders Subphylum Trilobita- trilobites (extinct)
Subphylum Chelicerata ~Named after mouthparts called chelicerae which appear as claws or fangs. They are used to pinch and pierce.
Remember Insects and Crustaceans are mandibulates *Remember Insects and Crustaceans are mandibulates. They have mandibles which they use for chewing.
Ecological Impact Positive Many arachnids help control the populations of many harmful insects Negative Harmful bites- spider Harmful stings- scorpions Transmit disease- ticks
Subphylum Chelicerata 1st pr of appendages are chelicera- mouthparts which may appear as claws or fangs Tagmata- specialized grouping of multiple segments: cephalothorax & abdomen 4 pr of walking appendages Respiration by book lungs 4 pair of simple eyes No mandibles No antennae Fig. 18.CO
Subphylum Chelicerata Class Arachnida Order Araneae Fig. 18.4
6 Pair of Appendages 1 pair of chelicerae in the form of poisonous fangs 1 pair of pedipalps used for sensory reception and transfer of sperm in the male 4 pair of walking legs No antennae
Most have 8 eyes
Feeding Fangs immobilize prey and then the spider injects digestive juices into the victim Later the spider sucks up the partially digested tissues of the prey Some spiders produce silk webs used to catch food Silk glands produce a protein secretion that hardens when it contacts the air Spinnerets- 2 or 3 pair of small projections at the posterior end of the abdomen where silk comes out.
Respiration Book lungs- air enters through a slit in the abdomen and flows between the pagelike folds where oxygen and carbon dioxide are exchanged Some spiders have tracheae- minute tubules that transport oxygen directly to tissues
Reproduction Not hermaphroditic - separate sexes - female often larger than male Pedipalps of male transfer sperm to seminal receptacle of female - Internal fertilization
Regional Poisonous Spiders Poison is a neurotoxin Lactrodectus mactans Loxosceles reclusa Poison destroys tissue
Golden Orb Spider/Garden Spider Argiope aurantia Tan Tarantula Aphonopelma anax
Class Arachnida, Order Opiliones Fig. 18.10b
Class Arachnida, Order Solifugae “camel spiders” Eremobates sp only grow to about 6 inches https://www.youtube.com/watch?v=G7fyLA_GGc4
Class Arachnida, Order Amblypygi “tailless whip scorpion”
Class Arachnida, Order Scorpiones Paninus imperator (Emperor scorpion)
Scorpions Pedipalps modified into pincers Segmented abdomen with a poisonous stinger in its last segment
Class Arachnida, Order Acari Mites and Ticks Bodies fused into unsegmented ovoid shapes Ticks (blood sucking parasites of vertebrates) transmit many different diseases Rocky mountain spotted fever Lyme disease Mites transmit some diseases - mainly just irritants http://www.idph.state.il.us/envhealth/pcmites.htm
Class Arachnida, Order Acari Rhipicephalus sanguineus Brown dog tick Dermacentor variabilis American dog tick Rocky mountain spotted fever http://www.cdc.gov/rmsf/index.html
Class Arachnida, Order Acari Ixodes scapularis Deer tick Lyme disease http://www.cdc.gov/lyme/
Class Arachnida, Order Acari Class Sarcoptes scabiei scabies mite Eutrombicula alfreddugesi Chigger Chiggers are unique among mites affecting humans and animals, in that the immature stage (the larva) is the only parasitic stage. http://www.cdc.gov/parasites/scabies/index.html
Subphylum Chelicerata Class Pycnogonida Fig. 18.3
Subphylum Chelicerata Class Merostomata Fig. 18.2a Limulus limus – horseshoe crab
Subphylum Chelicerata Class Merostomata Fig. 18.2b Spawning http://www.youtube.com/watch?v=wA-NoH_G330 Drug Purification Testing http://www.youtube.com/watch?v=90LTtKIFY8U