Classification- Phylum Classification- Phylum Arthropoda Arthropoda Chapter 19 Chapter 19 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 Chapter 20 Chapter 20 Subphylum Crustacea Subphylum Crustacea Chapter 21 Chapter 21 Subphylum Hexapoda Subphylum Hexapoda
Classification- Phylum Arthropoda Chapter 19 Subphylum Trilobita (extinct) Subphylum Chelicerata Class Arachnida Order Araneae Order Scorpiones Order Opiliones (Daddy Longlegs) Order Acari (Ticks and Mites) Subphylum Myriapoda Class Diplopoda Class Chilopoda Chapter 20 - PowerPoint PPT Presentation
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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
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
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;
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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,
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
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
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
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