Download - Classification- Phylum Arthropoda Chapter 19 Subphylum Trilobita (extinct) Subphylum Chelicerata
Classification- Phylum ArthropodaClassification- Phylum ArthropodaChapter 19Chapter 19Subphylum Trilobita (extinct)Subphylum Trilobita (extinct)Subphylum ChelicerataSubphylum Chelicerata
Class ArachnidaClass ArachnidaOrder AraneaeOrder AraneaeOrder ScorpionesOrder ScorpionesOrder Opiliones (Daddy Longlegs)Order Opiliones (Daddy Longlegs)Order Acari (Ticks and Mites)Order Acari (Ticks and Mites)
Subphylum MyriapodaSubphylum MyriapodaClass DiplopodaClass DiplopodaClass ChilopodaClass Chilopoda
Chapter 20Chapter 20Subphylum CrustaceaSubphylum Crustacea
Chapter 21Chapter 21Subphylum HexapodaSubphylum Hexapoda
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CHAPTER 19CHAPTER 19CHAPTER 19CHAPTER 19
Trilobites, Trilobites, Chelicerates, and Chelicerates, and
MyriapodsMyriapods
Trilobites, Trilobites, Chelicerates, and Chelicerates, and
MyriapodsMyriapods
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CharacteristicsCharacteristics
AnthropodizationAnthropodization Soft cuticle of the arthropod ancestors was Soft cuticle of the arthropod ancestors was
stiffened by deposition of stiffened by deposition of protein and chitinprotein and chitin Joints Joints had to provide flexibilityhad to provide flexibility Sequence of molts was necessary to allow Sequence of molts was necessary to allow
for growthfor growth Molting required Molting required hormonal controlhormonal control Hydrostatic skeleton function was lostHydrostatic skeleton function was lost
Coelom regressed and was replaced by open Coelom regressed and was replaced by open sinuses sinuses
Motile cilia were lostMotile cilia were lost
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Phylum ArthropodaPhylum Arthropoda Contains over 3/4 of all known speciesContains over 3/4 of all known species Coelomate protostomesCoelomate protostomes with well-developed with well-developed
organ systemsorgan systems SegmentedSegmented
CharacteristicsCharacteristics
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Sizes range from the Japanese crab (four meters in Sizes range from the Japanese crab (four meters in leg span) to the 0.1 mm long follicle miteleg span) to the 0.1 mm long follicle mite
Abundance and wide ecological distribution makes Abundance and wide ecological distribution makes them the them the most diverse animal groupmost diverse animal group
Some are agents of disease and compete with Some are agents of disease and compete with humans for foodhumans for food
Others are beneficialOthers are beneficial All modes of feeding occur among arthropods; All modes of feeding occur among arthropods;
carnivores, omnivores, herbivorous (most), carnivores, omnivores, herbivorous (most), decomposers, scavengers, parasites, etc.decomposers, scavengers, parasites, etc.
CharacteristicsCharacteristics
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Follicle Mite
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Relationships among arthropod subgroupsRelationships among arthropod subgroups Divided into Divided into subphylasubphyla based on relationships based on relationships
between subgroupsbetween subgroups Groupings among subphyla based on molecular Groupings among subphyla based on molecular
datadata Centipedes, millipedes are placed into Centipedes, millipedes are placed into
subphylum subphylum MyriapodaMyriapoda Insects are placed in subphylum Insects are placed in subphylum HexapodaHexapoda Spiders, and ticks form subphylum Spiders, and ticks form subphylum ChelicerataChelicerata Lobsters, crabs, barnacles, and others form Lobsters, crabs, barnacles, and others form
subphylum subphylum CrustaceaCrustacea
CharacteristicsCharacteristics
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2 Important Parts in Arthropods:
Appendages andMouthparts
Uniramous: single branchedBiramous: 2 branches
Chelicerae: pointed appendages to grasp foodMandible: chewing appendage
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Great Diversity and Abundance of ArthropodsGreat Diversity and Abundance of Arthropods
WHY HAVE ARTHROPODS SURVIVED…WHY HAVE ARTHROPODS SURVIVED… 1. Versatile Exoskeleton 1. Versatile Exoskeleton
Cuticle is highly protective and jointed, providing Cuticle is highly protective and jointed, providing mobilitymobility
Consists of inner thick Consists of inner thick procuticle procuticle and outer thin and outer thin epicuticleepicuticle
Procuticle has an Procuticle has an exocuticleexocuticle secreted before a molt secreted before a molt and an and an endocuticleendocuticle secreted after molting secreted after molting
Both layers of procuticle contain chitin bound with Both layers of procuticle contain chitin bound with proteinprotein
Procuticle is lightweight, flexible, and protects Procuticle is lightweight, flexible, and protects against dehydrationagainst dehydration
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Cuticle is further hardened by tanningCuticle is further hardened by tanning Ecdysis,Ecdysis, or molting or molting
Process of shedding outer covering and growing a new, Process of shedding outer covering and growing a new, larger onelarger one
Arthropods typically molt Arthropods typically molt four to sevenfour to seven times times
Great Diversity and Abundance of ArthropodsGreat Diversity and Abundance of Arthropods
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2. Segmentation and Appendages for 2. Segmentation and Appendages for Efficient LocomotionEfficient Locomotion Appendages often highly specialized for Appendages often highly specialized for division of labordivision of labor Limb segments are hollow levers with internal striated Limb segments are hollow levers with internal striated
musclesmuscles Appendages may function in sensing, food handling, Appendages may function in sensing, food handling,
walking, or swimmingwalking, or swimming
3. Use of Diverse Resources through 3. Use of Diverse Resources through MetamorphosisMetamorphosis Many arthropods undergo metamorphic changes leading to Many arthropods undergo metamorphic changes leading to
different larval and adult stagesdifferent larval and adult stages Larvae and adults feed on different organisms and occupy Larvae and adults feed on different organisms and occupy
different habitats different habitats Avoid competitionAvoid competition
Survival of ArthropodsSurvival of Arthropods
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4. Air Piped Directly to Cells4. Air Piped Directly to Cells Terrestrial arthropods Terrestrial arthropods
Use an efficient tracheal system for oxygen Use an efficient tracheal system for oxygen transport directly to tissuestransport directly to tissues
Aquatic arthropodsAquatic arthropods Respire via various forms of gillsRespire via various forms of gills
5. Highly Developed Sensory Organs5. Highly Developed Sensory Organs Eyes vary from simple light sensitive ocelli to a Eyes vary from simple light sensitive ocelli to a
compound mosaic eyecompound mosaic eye Other sensory structures for touch, smell, Other sensory structures for touch, smell,
hearing, balancing, and chemical receptionhearing, balancing, and chemical reception
Survival of ArthropodsSurvival of Arthropods
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Early Arthropod fossils: Trilobites and Eurypterid
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Subphylum ChelicerataSubphylum Chelicerata
CharacteristicsCharacteristics Chelicerates have Chelicerates have six pairssix pairs of of
cephalothoracic appendages including cephalothoracic appendages including chelicerae chelicerae (eating),(eating), pedipalps pedipalps (mating)(mating) and and four pair of legsfour pair of legs
Lack mandibles and antennaeLack mandibles and antennae Most suck liquid food from preyMost suck liquid food from prey Example: spiders, horseshoe crabs, sea Example: spiders, horseshoe crabs, sea
spiders, ticks, scorpionsspiders, ticks, scorpions
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Sea Spiders
Spiders
Horseshoe Crabs
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Horseshoe Crab: Illustrating 6 pairs of appendages
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Sea spiders: Illustrating 6 sets of appendages
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Class ArachnidaClass Arachnida Great diversity Great diversity Most are free living and more common in Most are free living and more common in
warm, dry regionswarm, dry regionsStructures Structures Divided into two body parts: Divided into two body parts: a cephalothorax a cephalothorax
and an abdomenand an abdomen Cephalothorax bears a pair of chelicerae, a Cephalothorax bears a pair of chelicerae, a
pair of pedipalps, and 4 pairs of walking legspair of pedipalps, and 4 pairs of walking legs No antenna and mandibles No antenna and mandibles Example: Spiders, Ticks, and ScorpionsExample: Spiders, Ticks, and Scorpions
Subphylum ChelicerataSubphylum Chelicerata
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Most are Most are predaceouspredaceous and have claws, fangs, and have claws, fangs, poison glands, or stingerspoison glands, or stingers
Sucking mouthparts ingest fluids and soft Sucking mouthparts ingest fluids and soft tissues from bodies of their preytissues from bodies of their prey
Spiders have spinning glandsSpiders have spinning glands PedipalpsPedipalps of males are modified, sometimes of males are modified, sometimes
elaborately, for sperm transferelaborately, for sperm transfer
Subphylum ChelicerataSubphylum Chelicerata
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Over 80,000 species have been Over 80,000 species have been describeddescribed
Most harmless to humans and provide Most harmless to humans and provide essential control of injurious insectsessential control of injurious insects
Some spiders are venomous and can Some spiders are venomous and can cause pain or death in humanscause pain or death in humans
Ticks may carry Ticks may carry human diseaseshuman diseases Mites can be Mites can be crop pestscrop pests
Subphylum ChelicerataSubphylum Chelicerata
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Order Araneae: SpidersOrder Araneae: Spiders Approximately 40,000 species Approximately 40,000 species Body consists of an Body consists of an unsegmented unsegmented
cephalothoraxcephalothorax and and abdomenabdomen joined by a joined by a slender slender pedicelpedicel
Anterior appendages are a pair of chelicerae Anterior appendages are a pair of chelicerae with terminal fangswith terminal fangs
Pair of Pair of pedipalps pedipalps have sensory functions and have sensory functions and are used by males to transfer spermare used by males to transfer sperm
Basal parts of pedipalps used to handle foodBasal parts of pedipalps used to handle food Four pairs of walking legs terminate in clawsFour pairs of walking legs terminate in claws All are predaceous,All are predaceous, mostly on insects mostly on insects
Subphylum ChelicerataSubphylum Chelicerata
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External Anatomy of Jumping Spider
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Injected venom liquefies and digests the tissues which Injected venom liquefies and digests the tissues which is sucked into spider’s stomachis sucked into spider’s stomach
RESPIRATORY SYSTEMRESPIRATORY SYSTEM Breathe by Breathe by book lungs and/or tracheabook lungs and/or trachea Book lungsBook lungs unique to spiders unique to spiders
Parallel air pockets extend into blood-filled chamberParallel air pockets extend into blood-filled chamber Air enters chamber through a slit in body wallAir enters chamber through a slit in body wall Trachea systemTrachea system
Transports air directly to tissues/blood through an opening Transports air directly to tissues/blood through an opening called a called a spiraclespiracle
Excretory SystemExcretory System In spiders and insects, In spiders and insects, Malpighian tubulesMalpighian tubules serve as serve as
excretory structures excretory structures Rectal glands reabsorb water. Conserves water and Rectal glands reabsorb water. Conserves water and
allows the organisms to live in dry environmentsallows the organisms to live in dry environments
Subphylum ChelicerataSubphylum Chelicerata
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Internal Anatomy of a Spider
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Sensory SystemsSensory Systems Most spiders have Most spiders have eight simple eyes,eight simple eyes, each each
with a lens, optic rods, and a retina with a lens, optic rods, and a retina Detect movement and may form imagesDetect movement and may form images
Sensory setae detect air currents, web Sensory setae detect air currents, web vibrations, and other stimulivibrations, and other stimuli
Vision is poor, rely on mechanoreceptors Vision is poor, rely on mechanoreceptors (stimuli)(stimuli)
Subphylum ChelicerataSubphylum Chelicerata
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Web-Spinning HabitsWeb-Spinning Habits Spinning silk critical ability for spiders Spinning silk critical ability for spiders Two or three pairs of Two or three pairs of spinneretsspinnerets contain contain
microscopic tubes that run to microscopic tubes that run to silk glandssilk glands Liquid scleroproteinLiquid scleroprotein secretion hardens as secretion hardens as
it is extruded from spinneretsit is extruded from spinnerets Silk threads are very strong and will Silk threads are very strong and will
stretch considerably before breakingstretch considerably before breaking Silk is used for orb webs, lining burrows, Silk is used for orb webs, lining burrows,
forming egg sacs, and wrapping preyforming egg sacs, and wrapping prey
Subphylum ChelicerataSubphylum Chelicerata
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Grasshopper snared in Golden Garden Spider silk.If the spider is not hungry, it will save the live prey for later.
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Fisher Spider: Catches prey, paralyzes them, pumps in digestive enzymes,
then sucks out predigested contents.
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ReproductionReproduction Before mating, male stores sperm in pedipalpsBefore mating, male stores sperm in pedipalps Mating involves inserting pedipalps into the Mating involves inserting pedipalps into the
female genital openingsfemale genital openings A A courtship ritualcourtship ritual is often required before the is often required before the
female will allow matingfemale will allow mating Eggs may develop in a cocoon in the web or may Eggs may develop in a cocoon in the web or may
be carried by femalebe carried by female Young hatch in about two weeks and may molt Young hatch in about two weeks and may molt
before leaving the egg cocoonbefore leaving the egg cocoon
Subphylum ChelicerataSubphylum Chelicerata
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Wolf spider with egg sack
Black Widow with egg sack
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Are spiders really dangerous? Are spiders really dangerous? Most people fear spiders without good reason Most people fear spiders without good reason Spiders are allies of humans in our battle with Spiders are allies of humans in our battle with
insectsinsects American tarantulasAmerican tarantulas rarely bite, and bite is not rarely bite, and bite is not
dangerous dangerous Species of Species of black widow spidersblack widow spiders are dangerous are dangerous
Venom is neurotoxicVenom is neurotoxic Brown recluse spiderBrown recluse spider
Hemolytic venom that destroys tissue around Hemolytic venom that destroys tissue around the bitethe bite
Some Australian and South American spiders are Some Australian and South American spiders are the most dangerous and aggressivethe most dangerous and aggressive
Subphylum ChelicerataSubphylum Chelicerata
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Tarantula: Not Dangerous. Bite similar to Bee StingBite when threatened or defending eggs/young.
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A: Black Widow displaying Red HourglassB: Brown Recluse Spider displaying violin marking on cephalothorax
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Order Scorpionida: ScorpionsOrder Scorpionida: Scorpions More common in tropical and subtropical More common in tropical and subtropical
zones but occur in temperate areaszones but occur in temperate areas Approximately 1,400 species worldwideApproximately 1,400 species worldwide Nocturnal and feed largely on insects and Nocturnal and feed largely on insects and
spidersspiders Sand-dwellers locate prey by detecting Sand-dwellers locate prey by detecting
surface waves with leg sensillaesurface waves with leg sensillae Appendages attached to cephalothorax Appendages attached to cephalothorax
Pair of medial eyes and 2–5 lateral eyesPair of medial eyes and 2–5 lateral eyes PreabdomenPreabdomen has 7 segments has 7 segments PostabdomenPostabdomen has long, slender tail of five has long, slender tail of five
segments that ends in a stinging apparatussegments that ends in a stinging apparatus
Subphylum ChelicerataSubphylum Chelicerata
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Emperor Scorpion with young. Young stay with mother until their first molt.
Harvestmen: Order OpilionesAKA- Daddy Longlegs
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Under the abdomen are comblike Under the abdomen are comblike pectinespectines Explore the ground and aid in sex Explore the ground and aid in sex
recognitionrecognition StingerStinger on last segment has venom that on last segment has venom that
varies from mildly painful to dangerousvaries from mildly painful to dangerous Ovoviviparous or viviparousOvoviviparous or viviparous and produce and produce
from 6 to 90 youngfrom 6 to 90 young Perform complex Perform complex mating dancesmating dances
In some species the male stings the female In some species the male stings the female on pedipalp or on edge of cephalothoraxon pedipalp or on edge of cephalothorax
Subphylum ChelicerataSubphylum Chelicerata
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Order Opiliones: HarvestmenOrder Opiliones: Harvestmen Harvestmen or Harvestmen or daddy longlegsdaddy longlegs Approximately 5,000 species worldwideApproximately 5,000 species worldwide Unlike spiders, abdomen and cephalothorax Unlike spiders, abdomen and cephalothorax
join broadly join broadly without a narrow pedicelwithout a narrow pedicel Can lose most of their eight long legs without Can lose most of their eight long legs without
ill effectill effect Chelicerae are pincerlike Chelicerae are pincerlike Mostly Mostly scavengers scavengers Have 2 eyes, not 8Have 2 eyes, not 8
Subphylum ChelicerataSubphylum Chelicerata
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Order Acari: Ticks and MitesOrder Acari: Ticks and Mites Medically and economically the most Medically and economically the most
important arachnidsimportant arachnids About 30,000 species have been described About 30,000 species have been described Both aquatic and terrestrialBoth aquatic and terrestrial
Inhabit deserts, polar areas, and hot springsInhabit deserts, polar areas, and hot springs Most mites are less than 1 millimeter longMost mites are less than 1 millimeter long Ticks may range up to 2 cmTicks may range up to 2 cm Complete fusionComplete fusion of cephalothorax and of cephalothorax and
abdomen abdomen No sign of external segmentationNo sign of external segmentation
Subphylum ChelicerataSubphylum Chelicerata
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Mouthparts on tip of the anterior Mouthparts on tip of the anterior capitulumcapitulum Chelicerae on each side help pierce, tear, or Chelicerae on each side help pierce, tear, or
grip foodgrip food Adult mites and ticks possess 4 pairs of legsAdult mites and ticks possess 4 pairs of legs Transfer sperm directly or by Transfer sperm directly or by
spermatophores spermatophores (packets of sperm)(packets of sperm) Egg hatches, releasing a six-legged larva Egg hatches, releasing a six-legged larva
Eight-legged nymph stages followEight-legged nymph stages follow
Subphylum ChelicerataSubphylum Chelicerata
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Wood TickAll stages are ectoparasites
Red Velvet Mite: TrombiculaOnly Larvae is ectoparasite
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House dust mites House dust mites Free-living and often cause allergiesFree-living and often cause allergies
Spider mites Spider mites One of many important agricultural pest mites One of many important agricultural pest mites
that suck out plant nutrientsthat suck out plant nutrients Chiggers Chiggers
Larval Larval TrombiculaTrombicula mites mites Feed on dermal tissues and cause skin irritationFeed on dermal tissues and cause skin irritation
Hair follicle mite Demodex Hair follicle mite Demodex Harmless but may cause mild dermatitisHarmless but may cause mild dermatitis
Subphylum ChelicerataSubphylum Chelicerata
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Human Follicle Mite
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Human itch miteHuman itch mite Causes intense itching Causes intense itching Popular in WWII - due to crowded conditions in Popular in WWII - due to crowded conditions in
which people livedwhich people lived
Subphylum ChelicerataSubphylum Chelicerata
Human Itch Mite
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Subphylum ChelicerataSubphylum Chelicerata
Ticks:Ticks: 2nd premier disease vector (after mosquito). 2nd premier disease vector (after mosquito). Species include:Species include:
IIxodesxodes Some carry Lyme diseaseSome carry Lyme diseaseBacterial infection dicovered in 1970, in the city of Lyme, Bacterial infection dicovered in 1970, in the city of Lyme,
Conneticut. Conneticut. DermacentorDermacentor
Transmit Rocky Mountain spotted feverTransmit Rocky Mountain spotted feverCattle tick Cattle tick
Transmits Texas cattle fever (Protozoan)Transmits Texas cattle fever (Protozoan)
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Tick: Carries Texas Cattle Fever
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Subphylum MyriapodaSubphylum Myriapoda
CharacteristicsCharacteristics Myriopods (“Many Footed”) include: Myriopods (“Many Footed”) include:
Chilopoda (centipedes)Chilopoda (centipedes) Diplopoda (millipedes)Diplopoda (millipedes)
Use trachea to transport respiratory gases to Use trachea to transport respiratory gases to all body tissue all body tissue
Excretion usually by Malpighian tubulesExcretion usually by Malpighian tubules
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Class ChilopodaClass Chilopoda CentipedesCentipedes Found under logs, bark and stonesFound under logs, bark and stones Carnivorous,Carnivorous, eating earthworms, cockroaches, eating earthworms, cockroaches,
and other insectsand other insects Centipedes usually have one pair of legs on Centipedes usually have one pair of legs on
each segmenteach segment Most harmless to humansMost harmless to humans
Few large, tropical centipedes are dangerousFew large, tropical centipedes are dangerous Approximately 3,000 species worldwideApproximately 3,000 species worldwide
Subphylum MyriapodaSubphylum Myriapoda
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Centipede from Amazon, Peru. Head of a Centipede
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Characteristics Characteristics Terrestrial and have flattened bodies with up Terrestrial and have flattened bodies with up
to 177 segmentsto 177 segments Each segment except the one behind the head Each segment except the one behind the head
and last twoand last two Bears a pair of jointed legsBears a pair of jointed legs
Appendages of first body segment form Appendages of first body segment form poison clawspoison claws
Head has one pair of Head has one pair of antennaeantennae Eyes on either side of the head consist of Eyes on either side of the head consist of
groups of groups of ocelliocelli
Subphylum MyriapodaSubphylum Myriapoda
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ReproductionReproduction Sexes separateSexes separate with unpaired gonads and with unpaired gonads and
paired ductspaired ducts Some lay eggs and others are viviparousSome lay eggs and others are viviparous Young resemble adults and Young resemble adults and do not undergo do not undergo
metamorphosismetamorphosis
Subphylum MyriapodaSubphylum Myriapoda
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Class DiplopodaClass Diplopoda Millipedes (double footed)Millipedes (double footed) Less active than centipedesLess active than centipedes
Walk with graceful rather than wriggling motionWalk with graceful rather than wriggling motion Most eat decayed plants but a few eat living Most eat decayed plants but a few eat living
plant tissueplant tissue Most are slow moving and roll into a coil for Most are slow moving and roll into a coil for
defensedefense Some Some secrete toxic or repellant fluidssecrete toxic or repellant fluids from from
special glands on side of bodyspecial glands on side of body More than 10,000 species of worldwideMore than 10,000 species of worldwide
Subphylum MyriapodaSubphylum Myriapoda
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Tropical millipede. Head of a Millipede
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Characteristics Characteristics Cylindrical bodiesCylindrical bodies with 25 to more than with 25 to more than
100 segments100 segments Short thorax consists of 4 segments, Short thorax consists of 4 segments,
each bearing one pair of legseach bearing one pair of legs Each abdominal segment has 2 sets of Each abdominal segment has 2 sets of
legslegs Head has 2 clusters of simple eyes and Head has 2 clusters of simple eyes and
a pair each of antennae and mandiblesa pair each of antennae and mandibles
Subphylum MyriapodaSubphylum Myriapoda
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ReproductionReproduction Appendages of seventh segment specialized Appendages of seventh segment specialized
as as copulatory organscopulatory organs After copulation, female lays eggs in a nest After copulation, female lays eggs in a nest
and guards themand guards them Larvae have only one pair of legs per Larvae have only one pair of legs per
segmentsegment
Subphylum MyriapodaSubphylum Myriapoda
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Classification- Phylum ArthropodaClassification- Phylum Arthropoda Subphylum Trilobita (extinct)Subphylum Trilobita (extinct) Subphylum ChelicerataSubphylum Chelicerata
Class ArachnidaClass Arachnida Order AraneaeOrder Araneae Order ScorpionesOrder Scorpiones Order Opiliones (Daddy Longlegs)Order Opiliones (Daddy Longlegs) Order Acari (Ticks and Mites)Order Acari (Ticks and Mites)
Subphylum MyriapodaSubphylum Myriapoda Class DiplopodaClass Diplopoda Class ChilopodaClass Chilopoda
Subphylum CrustaceaSubphylum Crustacea Subphylum HexapodaSubphylum Hexapoda
ClassificationClassification