ARTHROPODS BIOLOGY PROGRAM MOUNTAIN POINTE HIGH SCHOOL
Animals of Phylum Arthropoda Termites, ticks, scorpions, grasshoppers, flies, mosquitoes, lobsters, crabs, bugs,spiders, centipedes, millipedes, daphnia,crayfish,beetles,dragon flies, bees, wasps, daddy-long legs, mites, fleas, trilobites, butterflies, moths, barnacles, ants,……..and many many more!!!!! 1
ARTHROPOD CLASSES *ARACHNID - SPIDER *CRUSTACEAN - LOBSTER, SHRIMP *INSECTA - BEE, GRASSHOPPER *CHILOPODA - CENTIPEDE *DIPLOPODA - MILLIPEDE
Characteristics of Arthropods !! • Invertebrates with an exoskeleton! • Jointed appendages (legs) • Bilaterally symmetrical, protosome • Has a true coelom, mesoderm • Segmented body 2
What are the advantages or disadvantages of an exoskeleton?? • Protection -made of chitin and protein- hard and thick !! • Supports internal organs • Provides for muscle attachment • Heavy-disadvantage • Can’t grow, so it must be shed by molting periodically! 3
Segmentation • Most arthropods have three body segments! HEAD, THORAX, and ABDOMEN • Sometimes the head and thorax are fused together to form a CEPHALOTHORAX- like in lobsters! 4
How do Arthropods breathe?? • Some land Arthropods breathe through tiny openings on their body called spiracles which lead to tubes within the body called tracheal tubes! - crickets! • Other land arthropods (spiders) breathe using book lungs found just behind the legs on the body! 5
Senses found in Arthropods!- from a brain and ventral nerve chord!!! • Antennae are sensitive to movement, sound and chemicals! They are used for communication too. • Pheromones are chemical-odor signals given off by arthropods! • EYES - both simple and compound! (Simple eyes detect light/dark! Compound eyes have many lenses together forming an image! Excellent for detecting movement!) 6
Sight through a Bees Compound Eye Bee Sight Human Sight
Circulation and Digestion in Arthropods! • Open circulatory system- blood flows into spaces in the body- not kept in blood vessels! • Dorsal heart ! • Complete digestive system-mouth-crop-stomach-intestines-anus! • Digestive enzymes breakdown food! • Chewing mandibles , or sucking mouth parts are strong! • Malpigian Tubules filter wastes into the intestines! 7
Sexual Reproduction in Arthropods ! • Internal Fertilization- eggs protected inside female. • A few are hermaphrodites • Some show parthenogenesis- young forming from unfertilized eggs!
Arthropods and Humans ?? The Good, the Bad and the Ugly!!! • Great pollinators …bees, wasps! • Provide honey, shellac, wax and silk! • Alternative to pesticides - lady bugs, praying mantis • Used in genetic research to make artificial skin, surgical sutures, and anti-fungal medicine from crab shells! • Problems: eating our food! • Spread diseases- malaria, yellow fever!
Diversity - The Arachnids!!- spiders, scorpions, mites, and ticks! • 30,000 species of spiders - but only about a dozen are poisonous to humans! • 2 body parts - cephalothorax and abdomen! • Appendages- 2 Chelicera-fangs, two pedipalps for handling food and used in reproduction, and 8 legs!! • 2-6 silk glands in the abdomen-passing the liquid silk to the spinnerets which knit it into thread! • No mandibles - but a sucking stomach! • No antennae / Simples eyes -usually 8
Arachnids Chelicera
Diversity - The Crustaceans - crayfish, shrimp, lobsters, barnacles, crabs! • Gills for breathing • Largemandibles for crushing food!- jaws open side to side not up and down! • 2-pairs of antennae! • 2 stalked compound eyes! • 5 or more pairs of walking legs with 2 large chelipeds called pinchers! • No malpighian tubes --> mouth and anus
Crustacean Example - Crayfish
Diversity-Centipedes and Millipedes • Class Chilopoda- centipedes with one pair of legs per segment! • Centipedes are carnivorous- eating snails, slugs and worms- They bite!! • Class Diplopoda - millipedes with two pairs of legs per body segment! • Millipedes are herbivorous - eating roots and leaves • Millipedes don’t bite but they can spray a smelly-fluid from their stink glands!
CentipedeMillipede
INCOMPLETE METAMORPHOSIS COMPLETE METAMORPHOSIS The young looks totally different from the adult version. Ex. Larva - Pupa The young is a small version of the adult Ex. Egg - nymph - adult
Diversity-The Insects……bugs.com • 3-body parts- head-thorax-abdomen • Spiracles-tracheal tubes for breathing • 3-pairs of legs- antennae, both simple and compound eyes- • A tympanum for hearing • Sometimes wings- one or two pair • Malpighian tubes • Complete Metamorphosis- (butterflies-moths) egg-larva-pupa-adult !! • Incomplete Metamorphosis-( crickets, grasshoppers) egg- nymph-molt-nymph-molt-nymph-molt-adult
Complete Vs Incomplete Metamorphosis
