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“jointed foot” Insects, centipedes, millipedes, spiders, and crustaceans

“jointed foot” Insects, centipedes, millipedes, spiders, and crustaceans. Most extensive phyla. Population density. 1x10 19 individuals (insect) = 10 quintillion individuals =10 million million million. Arthropod Diversity. 1,004,898 described species as of 2009 ( Footit & Adler)

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“jointed foot” Insects, centipedes, millipedes, spiders, and crustaceans

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  1. “jointed foot” Insects, centipedes, millipedes, spiders, and crustaceans

  2. Most extensive phyla

  3. Population density • 1x1019 individuals (insect) • = 10 quintillion individuals • =10 million millionmillion

  4. Arthropod Diversity • 1,004,898 described species as of 2009 • (Footit & Adler) • True estimates most likely 5 million species (Erwin 1982) • 1 million described • 4 million undescribed

  5. Why have arthropods achieved such great diversity and abundance? • Small size • Less energy requirement • Habitats/ niches • Flight (some individuals) • Escape/dispersal • Cuticle • Protective/ efficient attachment for muscles • (more muscle mass per unit body mass) • Highly organized/ effective sensory neuro-motor system • Recognize integrate and respond to external and internal signals • High reproductive capacity • Differentiated stages • Larva vs adult

  6. General Characteristics • Jointed legs • Eucoelomate • Protostome • Exoskeleton • Chitin • Feeding • Carnivorous • Herbivorous • Omnivorous • Habitat • Air • Land • Freshwater • Marine • Parasitic (endo and exo) • Size • >0.1mm to 4 m

  7. Tagma- groups of fused segments 2 Tagma Cephalothorax Opistosoma

  8. Tagma- groups of fused segments 3Tagma Head Thorax Abdomen

  9. Phylum Arthropoda • Subphylum Chelicerata • Class Merostomata • Class Arachnida • Subphylum Crustacea • Subphylum Uniramia • Class Chilopoda • Class Diploda • Class Insecta

  10. Subphylum Chelicerata • 6 pairs of cephalothoracic appendages • Chelicerae (1 pair) • Pedipalps (1 pair) • Walking legs (4 pair) • No antenna • Two classes • Class Merostomata • Horseshoe crab • Class Arachnida • Spiders, scorpions, ticks and mites

  11. Mandibulates • Characteristics • Mouthparts are mandibles • One or two pairs of antennae • 3 tagma • Head • Thorax • Abdomen • Variable leg numbers • Insects, crustaceans, and myriapods

  12. Class Merostomata

  13. Class Arachnida • Spiders • Scorpions • Whip scorpions • Ticks • Mites • Harvestmen

  14. Araneae: Spiders • Respiration • Book lungs • Parallel air pockets extending into a blood filled chamber • Trachea • Air tubes connecting the outside directly to the blood

  15. Excretion • Malphighian tubules • Uric acid

  16. Sensory • Simple (poor vision movement not shapes) • Cuticular mechanoreceptors (sense vibrations/ air movements) • Sensory setae • Trichobothria • Slit sense organs

  17. Web spinning • Spinnerets/ silk glands • Scleroprotein (liquid but hardens as a result of being pulled) • Strong and stretchy • Stronger than steel but will stretch 1/5 their length before breaking

  18. Reproduction • Male spins web to drop sperm in, gathers it with his pedipalps and carries it to the females genital opening (lock and key) • Female lays eggs in a net (cocoon), she may carry it or attach it to a plant

  19. Venom • Largely harmless to people (2 exceptions) • Black widdowLatrodectusdectes • 4 to 5 out of 1000 bites are fatal • Brown Recluse Loxoscelesskelos • 0 proven fatalities , most bite heal on their own, 10% cause tissue damage warranting medical attention. • Neurotoxin • Disrupt nerve impulses • Hemalytic toxin • Destroys blood cells and linings of capillaries

  20. Mandibulates • 2 groups • Subphylum Crustacea • Subphylum Uniramia

  21. Subphylum Crustacea • Characteristics • Marine, fresh water and terrestrial • Two pair of antennae • Five or more pairs of legs • Biramious (two main branches) • Gills

  22. Internal Features • Hemocoel • Blood-filled body space • Muscular system • Antagonistic arrangement • Extensors- draw parts away from the body • Flexors- draw parts towards the body

  23. Circulatory System • Open circulatory system • No veins • No separation of blood from intestinal fluid • Blood leaves the heart by way of the arteries, circulates through the hemocoel, and returns to venous sinuses or spaces before it reenters the heart

  24. Respiratory system • Small • Gas exchange occurs over thin areas of the cuticle or the entire body • Large • Feather like gills

  25. Excretory system • No malpighian tubules • “green glands” • Pair of tubular structures located in the ventral part of their head next to the esophagus • Excretion of nitrogenous wastes (ammonia) takes place across the cuticle

  26. Nervous system • Fused ganglia (brain-ish) • Supraesophageal ganglia • Eyes and antennae • Subesophageal ganglia • Mouth and appendages • 2 ventral nerve chords • Sensory system • Eyes • Compound (ommatidia) • Tactile hairs

  27. Reproduction • Dioecious • Parthenogenic • Female lays unfertilized eggs which develop into young • Metamorphosis • Ecdyis • Shedding of the cuticle • Controlled by hormomes and external conditions

  28. Classes • Class Remipedia • Class Cephalocarida • Class Branchiopoda • Class Ostracoda • Class Maxillopoda • Class Malacostraca • Sowbugs- pillbugs • Sand fleas • Barnacles • Crabs, lobster, shrimp

  29. Subphylum Uniramia • 2 groups • Insects • Myriapods (centipedes and millipedes) • Many foot • Mostly terrestrial • Very few aquatic (freshwater) • One pair of antennae • Appendages uniramous (one)

  30. Myriapods • Many legged arthropods • All have one pair of antennae • Use trachea • Classes • Diploda • Millipedes • Chilopoda • centipedes

  31. Class Chilopoda • Centipedes • Flattened bodies • 1 pair of legs per metamere (segment) • 1 spiracle per metamere • 15-177 segments • Poisonous • Viviparious – (live birth) • Carnivorous • Cockroaches & other insects • Earthworms

  32. Class Diploda • Millipedes • 2 pairs of legs per metamere • 2 spiracles per metamere • 25-100 segments • Harmless • Herbivorous • Repugnatorial glands

  33. Class Insecta • 3 pairs of legs • 3 tagma • Head • Thorax • Abdomen • Distribution • Every continent except Antarctica • High level of adaptability and specificity

  34. External Anatomy • Sclerites- system of plates which comprise the exoskeleton

  35. Movement • Walking • Triangle legs/ tripod gait • Flight • Only invertebrates that can fly • Wings composed of cuticle • Most have 2 pair • Flies 1 pair + halteres • Direct flight muscles • Attach to the wing • Indirect flight muscles • Attach to the cuticle

  36. Nutrition • Digestive system • Foregut • Mouth- gizzard (proventriculus) • Cuticle lined • Midgut • Stomach and gastric ceca • Hindgut • Intestine-anus • Cuticle lined

  37. Feeding • Phytophagous/ herbivorous • Feeding on plants • Saprophagous • Feeding on dead animals • Detrivorous • Feeding on dead material • Predaceous • Parasitic • Hyperparasitism • Parasitoids

  38. Circulation • Open circulatory system • Hemolymph (blood) • Tubular heart • Limited oxygen transport

  39. Gas exchange • Tracheal system • Extensive network of thin-walled tubes that branch to every part of the body

  40. Reproduction • Dioecious • Strategies • Viviparious • Live birth • Parthenogenic • Growth and development of young without fertilization • Oviparious • Young develop from eggs laid outside the body • Ovoviparious • Young develop from eggs held within the female

  41. Metamorphosis • 3 types • Holometabolous“complete” • Egg, larvae, pupae, adult • Hemimetabolous “incomplete” • Egg, nymph, adult • Ametabolous “no” • Direct development

  42. Nervous system • Sense organs • Keen sense perception • Mechanoreception • Sensilla • Auditory reception • Setae/sensilla • Tympanic membrane • Chemoreception(taste or smell) • Mouthparts • Vision • 2 types of eyes • Simple (ocelli) • Compound (made of ommatidia)

  43. Defense • Mimicry • Imitation of a noxious/dangerous species by coloration • Crypsis • Camouflage • Chemical defense

  44. Insects and human welfare • Negative • Crop damage and loss • 75% loss pre pesticide • Disease • Malaria- kills 1.2 million people annually • Positive • Predaceous insects • Food production • Pollination • Efficient protein source

  45. Insect Orders

  46. Ephemeroptera • Mayflies

  47. Odonata • Dragonfly • “Tooth wing”

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