ARTHROPODS
CHAPTER 26
MRS.BENDER’S BIOLOGY
CHARACTERISTICS
• SEGMENTATION
• ALLOWS FOR EFFICIENT AND COMPLEX MOVEMENTS
• TWO OR THREE BODY PARTS
• HEAD: MOUTHPARTS, EYES, ANTENNAE
• THORAX: THE LEGS AND WINGS ARE ATTACHED
• ABDOMEN: CONTAINS DIGESTIVE AND REPRODUCTIVE ORGANS
• CEPHALOTHORAX: FUSED HEAD AND THORAX
• EXOSKELETON
• PROVIDES FRAMEWORK FOR SUPPORT, PROTECTION SOFT TISSUE, SLOWS WATER
LOSS, PLACE FOR MUSCLE ATTACHMENT
• MADE OF CHITIN
• VARIES IN THICKNESS
CHARACTERISTICS
• JOINTED APPENDAGES
• STRUCTURES LIKE LEGS AND ANTENNAE
• ADAPTED FOR FEEDING, MATING, SENSING, WALKING AND
SWIMMING
• MOLTING
• PROCESSES OF SHEDDING THE EXOSKELETON
• MUST SHED AS THEY GROW
• SECRETES A FLUID TO SOFTEN THE OLD WHILE FORMING THE
NEW
BODY STRUCTURES
• FEEDING
• MANDIBLES ADAPTED FOR BITING AND CHEWING
• MODIFIED: FEATHERY STRAINERS, NEEDLE FOR STABBING, CUTTING
SWORDS, SUCKING STRAWS
• HERBIVORES, OMNIVORES, PARASITES
• DIGESTION
• A COMPLETE ONE-WAY SYSTEM WITH A MOUTH, GUT, AND ANUS
• GLANDS WHICH PRODUCE ENZYMES
BODY STRUCTURES
• RESPIRATION
• AQUATIC ARTHROPODS
• GILLS TO EXCHANGE GASES THROUGH DIFFUSION
• CRAYFISH, CRABS, LOBSTERS
• TERRESTRIAL ARTHROPODS
• TRACHEAL TUBES
• AIR ENTERS THROUGH THE SPIRACLES, OPENINGS LOCATED ON THE SIDE OF THE
ABDOMEN, THEN TRAVEL THROUGH THE TUBES UNTIL IT REACHES THE MUSCLES.
• INSECTS
• BOOK LUNGS
• HIGHLY FOLDED SAC LIKE MEMBRANES WHICH TAKE IN AIR WHICH IS THEN
TRANSFERRED THROUGH THE TUBES.
• SPIDERS
BODY STRUCTURES
• CIRCULATION
• NOT USED TO CARRY OXYGEN
• USED TO TRANSPORT NUTRIENTS AND REMOVES WASTES
• BLOOD IS PUMPED BY A HEART INTO VESSELS WHICH CARRY BLOOD TO THE TISSUE, THEN
BLOOD EMPTIES INTO OPEN SPACES THEN IS RETURNED TO THE HEART
• KNOWN AS OPEN CIRCULATORY SYSTEM
• EXCRETION
• CELLULAR WASTES REMOVED THROUGH MALPIGHIAN TUBULES, ALSO USED TO PRESERVE
WATER
• MALPHIGHIAN TUBULES ARE ATTACHED TO AND EMPTY INTO THE GUT AND REMOVE
UNDIGESTED WASTES
• SOME HAVE NEPHRIDIA TO REMOVE CELLULAR WASTES
RESPOND TO STIMULI
• GANGLIA- GROUPS OF NERVE CELL BODIES WHICH TAKE IN MESSAGES AND SEND BACK
SIGNALS TO RESPOND
• VISION
• COMPOUND EYES WITH MANY FACETS, HELPS TO ANALYZE QUICK CHANGING
ENVIRONMENTS
• DETECT MOVEMENT OF PREY, MATES, PREDATORS
• SEE COLOR
• SIMPLE EYES
• THREE TO EIGHT WITH ONE LENS
• DISTINGUISHES LIGHT FROM DARK
• HEARING
• TYPANUM- FLATTENED MEMBRANE USED FOR HEARING
• CHEMICALS
• PHEROMONES- USED TO COMMUNICATE
SIGNAL MATES AND FEEDING
BODY STRUCTURES
• MOVEMENT
• CRAWL, RUN, CLIMB, DIG, SWIM, FLY
• MUSCLES ATTACH TO EXOSKELETON
• STRENGTH OF MUSCLE DEPENDS ON NERVE IMPULSES
• REPRODUCTION
• SEXUALLY
• HAVE SPECIALIZED STRUCTURES
• FEW ARE HERMAPHRODITES AND UNDERGO CROSS FERTILIZATION LIKE
BARNACLES
• BROOD OR INCUBATE BUT DO NOT CARE FOR THEIR YOUNG, SOME DO
CARE OR YOUNG: BEES AND FEW SPIDERS
CRUSTACEANS
• CRABS, SHRIMPS, LOBSTERS, CRAYFISH, BARNACLES
• CHARACTERISTICS
• MOST AQUATIC
• TWO PAIR OF ANTENNAE
• TWO COMPOUND EYES, OFTEN ON THE TIPS OF SLENDER MOVEABLE STALKS
• MANDIBLES OR CHEWING, OPEN AND CLOSE SIDE TO SIDE
• FREE SWIMMING LARVAL STAGE CALLED A NAUPLIS
• MOST HAVE FIVE PAIRS OF LEGS
• CHELIPADS FIRST PAIR, LARGE CLAWS USED TO CATCH AND CRUSH FOOD
• FOUR PAIRS OF WALKING LEGS USED FOR LOCOMOTION
• SWIMMERETS, SHORT LEGS USED FOR REPRODUCTION AND DURING SWIMMING
ARACHNIDA
• SPIDERS, TICKS, MITES, SCORPIONS
• TWO BODY SECTIONS: CEPHALOTHORAX AND ABDOMEN
• FOUR PAIR WALKING LEGS
• NO ANTENNAE
• CHELICERAE- MODIFIED FANGS OR PINCERS USUALLY ATTACHED TO POISON
SACK
• ONLY POISONOUS SPIDER U.S. IS BLACK WIDOW AND BROWN RECLUSE
• PEDIPALPS-USED FOR SENSING AND HOLDING PREY, REPRODUCTION IN MALE
SPIDERS, AND PINCERS IN SCORPIONS
ARACHNIDIA
• SPIDERS
• CARNIVORES BY HUNTING OR CATCHING PREY
• SPINNERETS- STRUCTURE IN WHICH SILK IS SECRETED FOR SPINNING WEBS,
LOCATED ON ABDOMEN
• WRAP FOOD IN SILKEN COCOON UNTIL READY TO EAT
• DIGESTION BEGINS EXTERNALLY BY SECRETING DIGESTIVE ENZYMES INTO
PREY
• AFTER LIQUIDIFICATION, SOFTEN FOOD IS INGESTED
• REPRODUCTION
• MALE DEPOSITS SPERM AND STORED IT IN THE CAVITY ON HIS
PEDIPALPS
ARACHNIDIA
• SCORPIONS
• CARNIVORES, FEED ON INSECTS, SPIDERS AND SMALL VERTEBRATES
• CAPTURE WITH THE PEDIPALPS AND TEAR APART WITH CHELICERAE
• NOCTURNAL
• MOST IN U.S. NOT POISONOUS TO HUMANS BUT STING IS PAINFUL
• TICKS
• PARASITES
• CARRY DISEASE CAUSING ORGANISMS
• MITES
• PREDATORS OR PARASITES
• HORSHOE CRAB
• ANCESTORS WHICH ARE MARINE
INSECTA
• 30 MILLION SPECIES
• 80% ARTHROPODS ARE INSECTS
• TERRESTRIAL LIVING IN ALL ENVIRONMENTS
• HARD EXOSKELETON PROTECTS THEM FROM PREDATORS AND DRYING OUT
• REPRODUCTION LARGE NUMBERS
INSECTA EXTERNAL FEATURES
• THREE BODY PARTS
• HEAD
• CONTAINS ANTENNAE, COMPOUND EYES, SIMPLE EYES, MOUTHPARTS
• THORAX
• THREE PAIRS OF LEGS
• GENERALLY TWO PAIR OF WINGS
• ABDOMEN
• CONTAINS DIGESTION ORGANS
• CONTAINS REPRODUCTIVE ORGANS
INSECTA ADAPTATIONS
• LEGS
• CLAWS FOR DIGGING
• STICKY PADS TO WALK UPSIDE DOWN
• COLLECTION OF POLLEN
• JUMPING
• SKIMMING OVER WATER
• MOUTHPARTS
• SIPHONING; FEEDING TUBE UNCOILS AND EXTENDED TO SUCK : BUTTERFLIES AND MOTHS
• SPONGING; FLESHY END OF MOUTH ACTS LIKE A SPONGE; HOUSE FLIES
• PIERCING/SUCKING; NEEDLE LIKE TUBE PIERCE AND SUCKS: MOSQUITOES, FLEAS,
LEAFHOPPERS
• CHEWING; MANDIBLE PIERCES OR CUTS, OTHER PARTS BRING FOOD TO MOUTH: BEETLES,
ANTS,BEES, GRASSHOPPERS
INSECTA ADAPTATIONS
• ONLY INVERTEBRATES THAT CAN FLY
• WINGS
• FORMED FROM THIN MEMBRANE OF CHITIN
• RIGID VEIN THAT GIVE STRENGTH
• BUTTERFLY AND MOTH WINGS COVERED WITH SCALES
• ROTATE IN FIGURE 8 TO FLY
• SENSE ORGANS
• ANTENNAE AND EYES
• HAIRLIKE STRUCTURES SENSITIVE TO TOUCH, PRESSURE, VIBRATION AND
ODOR
• CHEMICAL RECEPTORS FOR TASTE AND SMELL LOCATED ON MOUTH PARTS
METAMORPHOSIS
• SERIES OF CHANGES
• COMPLETE METAMORPHOSIS
• 4 STAGES
• EGG…..LARVA…..PUPA…..ADULT
• WORMLIKE LARVA IS CALLED A CATERPILLAR
• PUPA IS A NON FEEDING STAGE
• INCOMPLETE METAMORPHOSIS
• 3 STAGES
• EGG….NYMPH……ADULT
• NYMPH IS THE IMMATURE FORM OF ADULT WITHOUT WINGS
INSECT SOCIETIES
• CASTE IS A GROUP OF INDIVIDUALS WITHIN A SOCIETY THAT PERFORM A
SPECIFIC TASK
• BEES
• WORKERS: FEMALES THAT DO NOT REPRODUCE…GATHER NECTAR AND
POLLEN…BUILD HONEYCOMB…CARE FOR YOUNG…GUARD THE HIVE
• DRONES: REPRODUCTIVE MALES, DIE AFTER MATING
• QUEEN: ONLY REPRODUCTIVE FEMALE
INSECTS AND HUMANS
• NEEDS FOR POLLINATION
• PRODUCE HONEY AND SILK
• SERVE AS FOOD FOR ANIMALS
• PREY ON PLANT PESTS
• HARMFUL AS PARASITES AND CARRY DISEASE