Classification- Phylum Arthropoda Chapter 19 Subphylum Trilobita (extinct) Subphylum Trilobita (extinct) Subphylum Chelicerata Subphylum Chelicerata Class Arachnids Class Arachnids Order Araneae (spiders) Order Araneae (spiders) Order Scorpiones Order Scorpiones Order Opiliones (Daddy Longlegs) Order Opiliones (Daddy Longlegs) Order Acari (Ticks and Mites) Order Acari (Ticks and Mites) Subphylum Myriapoda Subphylum Myriapoda Class Diplopoda (millipedes) Class Diplopoda (millipedes) Class Chilopoda (centipedes) Class Chilopoda (centipedes) Chapter 20 Subphylum Crustacea Subphylum Crustacea Chapter 21 Subphylum Hexapoda Subphylum Hexapoda

19-2 CHAPTER 19 Trilobites, Chelicerates, and Myriapods Trilobites, Chelicerates, and Myriapods

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Characteristics Anthropod Characteristics Exoskeleton - Soft cuticle stiffened by deposition of protein and chitin Exoskeleton - Soft cuticle stiffened by deposition of protein and chitin Joints had to provide flexibility Joints had to provide flexibility Sequence of molts to allow for growth Sequence of molts to allow for growth Molting required hormonal control - ecdysone Molting required hormonal control - ecdysone

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Phylum Arthropoda Contains over 3/4 of all known species Contains over 3/4 of all known species Coelomate protostomes with well-developed organ systems Coelomate protostomes with well-developed organ systems Complete Digestive Tract Complete Digestive Tract Segmented - tagmata Segmented - tagmata Fused segments = tagmata (ex. head, thorax, abdomen) Fused segments = tagmata (ex. head, thorax, abdomen) Characteristics

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Sizes range from the Japanese crab (four meters in leg span) to the 0.1 mm long follicle mite Sizes range from the Japanese crab (four meters in leg span) to the 0.1 mm long follicle mite most diverse animal group most diverse animal group Some are agents of disease and compete with humans for food Some are agents of disease and compete with humans for food Others are beneficial Others are beneficial All modes of feeding occur among arthropods; carnivores, omnivores, herbivorous (most), decomposers, scavengers, parasites, etc. All modes of feeding occur among arthropods; carnivores, omnivores, herbivorous (most), decomposers, scavengers, parasites, etc. Characteristics

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Japanese Spider Crap 4 M in length Follicle Mite 0.1 mm in length

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Relationships among arthropod subgroups Divided into subphyla Divided into subphyla Centipedes, millipedes are placed into subphylum Myriapoda Centipedes, millipedes are placed into subphylum Myriapoda Insects are placed in subphylum Hexapoda Insects are placed in subphylum Hexapoda Spiders, and ticks form subphylum Chelicerata Spiders, and ticks form subphylum Chelicerata Lobsters, crabs, barnacles, and others form subphylum Crustacea Lobsters, crabs, barnacles, and others form subphylum Crustacea Characteristics

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Important Parts in Arthropods: Appendages and Mouthparts Uniramous: single branched Biramous: 2 branches Chelicerae: pointed appendages to grasp food Mandible: chewing appendage

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Arthropod Characteristics WHY HAVE ARTHROPODS SURVIVED…(Top 5 Reasons) million years old 1. Versatile Exoskeleton 1. Versatile Exoskeleton Cuticle is protective and jointed, providing mobility Cuticle is protective and jointed, providing mobility Consists of inner thick molting procuticle (made of exocuticle and endocuticle) and outer thin epicuticle Consists of inner thick molting procuticle (made of exocuticle and endocuticle) and outer thin epicuticle Ecdysis, or molting Ecdysis, or molting Process of shedding outer covering and growing a new, larger one Process of shedding outer covering and growing a new, larger one Arthropods typically molt four to seven times Arthropods typically molt four to seven times Controlled by hormones and environmental cues Controlled by hormones and environmental cues

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Segmentation and Appendages 2. Segmentation and Appendages Paired Appendages specialized for division of labor (sensing, food handling, walking, or swimming) Paired Appendages specialized for division of labor (sensing, food handling, walking, or swimming) 3. Metamorphosis 3. Metamorphosis Larvae and adults feed on different organisms and occupy different habitats Larvae and adults feed on different organisms and occupy different habitats Avoid competition Avoid competition Survival of Arthropods

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Air Piped Directly to Cells 4. Air Piped Directly to Cells Terrestrial arthropods Terrestrial arthropods Use tracheal system for oxygen transport directly to tissues Use tracheal system for oxygen transport directly to tissues Aquatic arthropods Aquatic arthropods Respire via gills Respire via gills 5. Highly Developed Sensory Organs 5. Highly Developed Sensory Organs Eyes vary from simple light sensitive ocelli to a compound mosaic eye Eyes vary from simple light sensitive ocelli to a compound mosaic eye Other sensory structures for touch, smell, hearing, balancing, and chemical reception Other sensory structures for touch, smell, hearing, balancing, and chemical reception Survival of Arthropods

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Early Arthropod fossils: Trilobites and Eurypterid Subphylum Trilobita - extinct for over 200 million years

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Subphylum Chelicerata Chelicerata Characteristics Chelicerates have six pairs of cephalothoracic appendages including chelicerae (eating), pedipalps (mating) and four pair of legs Chelicerates have six pairs of cephalothoracic appendages including chelicerae (eating), pedipalps (mating) and four pair of legs Lack mandibles and antennae Lack mandibles and antennae Most suck liquid food from prey Most suck liquid food from prey Example: spiders, horseshoe crabs, sea spiders, ticks, scorpions Example: spiders, horseshoe crabs, sea spiders, ticks, scorpions

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Class Arachnida Structures Divided into two body parts: a cephalothorax and an abdomen Divided into two body parts: a cephalothorax and an abdomen Cephalothorax bears ALL appendages Cephalothorax bears ALL appendages Example: Spiders, Ticks, and Scorpions Example: Spiders, Ticks, and Scorpions Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Most are predaceous and have claws, fangs, poison glands, or stingers Most are predaceous and have claws, fangs, poison glands, or stingers Sucking mouthparts ingest fluids and soft tissues from bodies of their prey Sucking mouthparts ingest fluids and soft tissues from bodies of their prey Pedipalps of males are modified, sometimes elaborately, for sperm transfer Pedipalps of males are modified, sometimes elaborately, for sperm transfer Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Most harmless to humans and provide essential control of injurious insects Most harmless to humans and provide essential control of injurious insects Some spiders are venomous and can cause pain or death in humans Some spiders are venomous and can cause pain or death in humans Ticks may carry human diseases Ticks may carry human diseases Mites can be crop pests Mites can be crop pests Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Order Araneae: Spiders Approximately 40,000 species Approximately 40,000 species Body consists of an unsegmented cephalothorax and abdomen Body consists of an unsegmented cephalothorax and abdomen Anterior appendages are a pair of chelicerae with terminal fangs Anterior appendages are a pair of chelicerae with terminal fangs Pair of pedipalps are used by males to transfer sperm and handle food Pair of pedipalps are used by males to transfer sperm and handle food Four pairs of walking legs terminate in claws Four pairs of walking legs terminate in claws All are predaceous, mostly on insects All are predaceous, mostly on insects Subphylum Chelicerata

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Injected venom liquefies and digests the tissues which is sucked into spider’s stomach Injected venom liquefies and digests the tissues which is sucked into spider’s stomach RESPIRATORY SYSTEM (Book lungs or Trachea) RESPIRATORY SYSTEM (Book lungs or Trachea) Book lungs unique to spiders Book lungs unique to spiders Parallel air pockets extend into blood-filled chamber Parallel air pockets extend into blood-filled chamber Air enters chamber through a slit in body wall Air enters chamber through a slit in body wall Trachea system Trachea system Transports air directly to tissues/blood through an opening called a spiracle Transports air directly to tissues/blood through an opening called a spiracle Excretory System Excretory System In spiders and insects, Malpighian tubules serve as excretory structures In spiders and insects, Malpighian tubules serve as excretory structures Subphylum Chelicerata

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Sensory Systems Sensory Systems Most spiders have eight simple eyes, each with a lens, optic rods, and a retina Most spiders have eight simple eyes, each with a lens, optic rods, and a retina Detect movement and may form images (overall poor vision) Detect movement and may form images (overall poor vision) Sensory hairs detect air currents, web vibrations, and other stimuli Sensory hairs detect air currents, web vibrations, and other stimuli Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Web-Spinning Habits Web-Spinning Habits Spinning silk critical ability for spiders Spinning silk critical ability for spiders Two or three pairs of spinnerets contain microscopic tubes that run to silk glands Two or three pairs of spinnerets contain microscopic tubes that run to silk glands Liquid scleroprotein secretion hardens as it is extruded from spinnerets Liquid scleroprotein secretion hardens as it is extruded from spinnerets Silk threads are very strong and will stretch considerably before breaking Silk threads are very strong and will stretch considerably before breaking Silk is used for orb webs, lining burrows, forming egg sacs, and wrapping prey Silk is used for orb webs, lining burrows, forming egg sacs, and wrapping prey Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Grasshopper snared in Golden Garden Spider silk. If the spider is not hungry, it will save the live prey for later.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fisher Spider: Catches prey, paralyzes them, pumps in digestive enzymes, then sucks out predigested contents.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Reproduction Reproduction Before mating, male stores sperm in pedipalps Before mating, male stores sperm in pedipalps Mating involves inserting pedipalps into the female genital openings Mating involves inserting pedipalps into the female genital openings Use a courtship ritual Use a courtship ritual Eggs may develop in a cocoon in the web or carried by female Eggs may develop in a cocoon in the web or carried by female Young hatch in about two weeks and may molt before leaving the egg cocoon Young hatch in about two weeks and may molt before leaving the egg cocoon Subphylum Chelicerata

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Are spiders really dangerous? Are spiders really dangerous? American tarantulas rarely bite, and bite is not dangerous American tarantulas rarely bite, and bite is not dangerous Species of black widow spiders are dangerous Species of black widow spiders are dangerous Venom is a neurotoxin Venom is a neurotoxin Brown recluse spider Brown recluse spider Hemolytic venom that destroys tissue around the bite Hemolytic venom that destroys tissue around the bite Some Australian and South American spiders are the most dangerous and aggressive Some Australian and South American spiders are the most dangerous and aggressive Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Tarantula: Not Dangerous. Bite similar to Bee Sting Bite when threatened or defending eggs/young.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display A: Black Widow displaying Red Hourglass B: Brown Recluse Spider displaying violin marking on cephalothorax

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Order Scorpionida: Scorpions Approximately 1,400 species worldwide Approximately 1,400 species worldwide Nocturnal and feed largely on insects and spiders Nocturnal and feed largely on insects and spiders Sand-dwellers locate prey by detecting surface waves with leg hairs Sand-dwellers locate prey by detecting surface waves with leg hairs Appendages attached to cephalothorax Appendages attached to cephalothorax Pair of medial eyes and lateral eyes Pair of medial eyes and lateral eyes Preabdomen has 7 segments Preabdomen has 7 segments Postabdomen has long, slender tail of five segments that ends in a stinging apparatus Postabdomen has long, slender tail of five segments that ends in a stinging apparatus Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Scorpion epicuticle is fluorescent when exposed to UV light.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Stinger on last segment has venom that varies from mildly painful to dangerous Stinger on last segment has venom that varies from mildly painful to dangerous Perform complex mating dances Perform complex mating dances Ovoviviparous or viviparous and produce from 1 to 100 young Ovoviviparous or viviparous and produce from 1 to 100 young Gestation is from several months to a year Gestation is from several months to a year Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Emperor Scorpion with young. Young stay with mother until their first molt. (Gestation is up to a year, and 1 month on back) Life span of a scorpion is about 15 years Harvestmen: Order Opiliones AKA- Daddy Longlegs

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Order Opiliones: Harvestmen Harvestmen or daddy longlegs Harvestmen or daddy longlegs Approximately 5,000 species worldwide Approximately 5,000 species worldwide Unlike spiders, abdomen and cephalothorax join broadly Unlike spiders, abdomen and cephalothorax join broadly Can lose most of their eight long legs without ill effect Can lose most of their eight long legs without ill effect Chelicerae are pincerlike - can’t bite a human Chelicerae are pincerlike - can’t bite a human Are NOT venomous to humans Are NOT venomous to humans Mostly scavengers Mostly scavengers Have 2 eyes, not 8 Have 2 eyes, not 8 Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Order Acari: Ticks and Mites Medically and economically the most important arachnids Medically and economically the most important arachnids About 30,000 species have been described About 30,000 species have been described Most mites are less than 1 millimeter long Most mites are less than 1 millimeter long Ticks may range up to 2 cm Ticks may range up to 2 cm Complete fusion of cephalothorax and abdomen Complete fusion of cephalothorax and abdomen No sign of external segmentation No sign of external segmentation Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Mouthparts on tip of the anterior capitulum Mouthparts on tip of the anterior capitulum Chelicerae on each side help pierce, tear, or grip food Chelicerae on each side help pierce, tear, or grip food Adult mites and ticks possess 4 pairs of legs Adult mites and ticks possess 4 pairs of legs Transfer sperm directly or by spermatophores (packets of sperm) Transfer sperm directly or by spermatophores (packets of sperm) Subphylum Chelicerata

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Wood Tick All stages are ectoparasites Red Velvet Mite: Trombicula Similar to chiggers, only Larvae is ectoparasite. Nymphs and Adults are free-living.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display House dust mites House dust mites Free-living and often cause allergies Free-living and often cause allergies Spider mites Spider mites One of many important agricultural pest mites that suck out plant nutrients One of many important agricultural pest mites that suck out plant nutrients Chiggers Chiggers Larval stage feed on dermal tissues and cause skin irritation Larval stage feed on dermal tissues and cause skin irritation Hair follicle mite Demodex Hair follicle mite Demodex Harmless but may cause mild dermatitis Harmless but may cause mild dermatitis Subphylum Chelicerata

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Human itch mite Human itch mite Causes intense itching Causes intense itching Popular in WWII - due to crowded conditions in which people lived (Scabies) Popular in WWII - due to crowded conditions in which people lived (Scabies) Subphylum Chelicerata Human Itch Mite

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Subphylum Chelicerata Ticks: 2nd premier disease vector (after mosquito). Ticks: 2nd premier disease vector (after mosquito). Some carry Lyme disease (bacteria) Some carry Lyme disease (bacteria) Bacterial infection dicovered in 1970, in the city of Lyme, Conneticut. Bacterial infection dicovered in 1970, in the city of Lyme, Conneticut. Transmit Rocky Mountain spotted fever (bacteria) Transmit Rocky Mountain spotted fever (bacteria) Transmits Texas cattle fever (Protozoan) Transmits Texas cattle fever (Protozoan)

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Subphylum Myriapoda Characteristics Myriapods (“Many Footed”) include: Myriapods (“Many Footed”) include: Chilopoda (centipedes) Chilopoda (centipedes) Diplopoda (millipedes) Diplopoda (millipedes) Use trachea to transport respiratory gases to all body tissue Use trachea to transport respiratory gases to all body tissue Excretion usually by Malpighian tubules Excretion usually by Malpighian tubules

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Class Chilopoda Centipedes Centipedes Found under logs, bark and stones Found under logs, bark and stones Carnivorous, eating earthworms, cockroaches, and other insects (use poison claw) and then chew prey with mandible Carnivorous, eating earthworms, cockroaches, and other insects (use poison claw) and then chew prey with mandible Centipedes have one pair of legs on each segment (except 1st and last 2) Centipedes have one pair of legs on each segment (except 1st and last 2) Most harmless to humans Most harmless to humans Few large, tropical centipedes are dangerous Few large, tropical centipedes are dangerous Approximately 3,000 species worldwide Approximately 3,000 species worldwide Subphylum Myriapoda

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Characteristics Appendages of first body segment form poison claws - comparable to wasp sting Appendages of first body segment form poison claws - comparable to wasp sting Head has one pair of antennae Head has one pair of antennae Eyes on either side of the head consist of ocellus Eyes on either side of the head consist of ocellus Subphylum Myriapoda

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Reproduction Sexes separate Sexes separate Most lay eggs and guard them (oviparous), few are viviparous Most lay eggs and guard them (oviparous), few are viviparous Young resemble adults and do not undergo metamorphosis Young resemble adults and do not undergo metamorphosis Legs and segments are added with each molt Legs and segments are added with each molt Subphylum Myriapoda

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Class Diplopoda Millipedes (double footed) -10,000 species Millipedes (double footed) -10,000 species Less active than centipedes Less active than centipedes Walk with graceful rather than wriggling motion Walk with graceful rather than wriggling motion Most eat decayed plants but a few eat living plant tissue - use mandible Most eat decayed plants but a few eat living plant tissue - use mandible Most are slow moving and roll into a coil for defense Most are slow moving and roll into a coil for defense Some secrete toxic or repellant fluids from special glands on side of body (hydrogen cyanide) Some secrete toxic or repellant fluids from special glands on side of body (hydrogen cyanide) Subphylum Myriapoda

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Tropical millipede. Head of a Millipede

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Characteristics Cylindrical bodies with 25 to more than 100 segments Cylindrical bodies with 25 to more than 100 segments Short thorax consists of 4 segments, each bearing one pair of legs Short thorax consists of 4 segments, each bearing one pair of legs Each abdominal segment has 2 sets of legs Each abdominal segment has 2 sets of legs Head has 2 clusters of simple eyes and a pair of antennae and mandibles Head has 2 clusters of simple eyes and a pair of antennae and mandibles Subphylum Myriapoda

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Reproduction Appendages of seventh segment specialized as copulatory organs Appendages of seventh segment specialized as copulatory organs After copulation, female lays eggs in a nest and guards them After copulation, female lays eggs in a nest and guards them Larvae have only one pair of legs per segment, as they molt more legs and body segments are acquired Larvae have only one pair of legs per segment, as they molt more legs and body segments are acquired Subphylum Myriapoda

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Classification- Phylum Arthropoda Subphylum Trilobita (extinct) Subphylum Trilobita (extinct) Subphylum Chelicerata Subphylum Chelicerata Class Arachnida Class Arachnida Order Araneae Order Araneae Order Scorpiones Order Scorpiones Order Opiliones (Daddy Longlegs) Order Opiliones (Daddy Longlegs) Order Acari (Ticks and Mites) Order Acari (Ticks and Mites) Subphylum Myriapoda Subphylum Myriapoda Class Diplopoda Class Diplopoda Class Chilopoda Class Chilopoda Subphylum Crustacea Subphylum Crustacea Subphylum Hexapoda Subphylum Hexapoda Classification