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