110 likes | 360 Views
Phylum Arthropoda. “Jointed feet”. Introduction. The arthropods are by far the most successful phylum of animals About 80% of all known animal species belong to the Arthropoda / 800 000 described species/ Estimated to be around 6M species!
E N D
Phylum Arthropoda “Jointed feet”
Introduction • The arthropods are by far the most successful phylum of animals • About 80% of all known animal species belong to the Arthropoda / 800 000 described species/ Estimated to be around 6M species! • Arthropods are found in a greater variety of habitats than any other animal group • Now extinct, TRILOBITES represent the oldest known examples of arthropods.
Basic Morphology • Bilateral symmetry • Coelomate • Metamorphose • Protostomic • Chitinous exoskeleton • Jointed limbs moving in one plane • Metameric body split into tagmata • Complete digestive system • Respiration by body surface, trachea, gills, book lungs • Malphigian tubules for excretion • Open circulatory system • Complete nervous system • Heterosexual, internal fertilization • Regeneration
Specific Structural and Physiological Features • Tagmatization • Musculature • Cuticle • Circulation • TAGMATIZATION…tendency in the arthropods for segments to fuse together to form multisegmental units
Specific Structural and Physiological Features • Tagmatization • Musculature • Cuticle • Circulation • Complex muscular system • Striated muscles are attached to cuticle • Molting
Specific Structural and Physiological Features • Tagmatization • Musculature • Cuticle • Circulation • Open circulatory system • Haemocoel filled with blood
Trilobita • Trilobites probably rank second only to the dinosaurs in fame. • One of the best-known and most-studied groups of fossil arthropods • Trilobites ("three lobes") 1 Axial lobe 2 pleural lobes
Chelicerata • Includes spiders and scorpions, mites and ticks, horseshoe crabs, daddy-longlegs, and extinct "sea-scorpions", etc. • Six pairs of appendages: the chelicerae, a pair of pedipalps and 4 pairs of walking legs. • Lack Antennae
Crustacea • Includes lobsters, crabs, shrimp, pill bugs, krill, barnacles, water fleas, etc • 2 pairs of antennae at some stage • 5 segments on the head part and variable segments for body part( 8-32) • With carapace or cephalic shield • One pair of appendage per segment *Shape of Life 1
Uniramia …the largest group! • Includes beetles, centipedes (Chilopoda), millipedes (Diplopoda), flies---insects and all their relatives • Six-legged organisms (Insecta-3 pairs) • Legs have only one branch • 1 pair of wings vs. 2 pairs of wings *Shape of Life 2
Blattodea- cockroaches Isoptera- termites Odonata- dragonfly Phasmida- stick insects Pthiraptera- louse Siphonaptera- flea *Shape of Life 3