Invertebrates

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Invertebrates

  1. 1. Invertebrates• Sponges, Cnidarians, Worms, Mollusks, Annelids, Arthropods, Echinoderms• Each group of organisms have specific forms and functions• Feeding• Respiration, circulation and excretion• Response• Movement• Reproduction
  2. 2. Worms• Free-living or parasites• Segmented or unsegmented• Flatworms – soft, flattened worms that have tissues and internal organ systems,• simplest animals to have three embryonic germ layers (ectoderm, endoderm, mesoderm), bilateral symmetry and cephalization• Carnivores – single opening for digestive system• Use diffusion to move materials• Use ganglia (bundle of nerve cells) to respond to external stimuli
  3. 3. Cont.• Cilia and muscles are used for movement• Reproduce using sexual (hermaphordites) or asexual by the process of fission (splitting)• Three groups;• Turbellarians – free-living, fresh or marine water• Flukes – parasitic, internal organs (blood)• Tapeworms-parasitic, intestines
  4. 4. Nematoda• Roundworms are unsegmented worms that have two opening, anus and mouth• Have specializes tissue and organ systems• Consumers• Diffusion to move materials• Very simple nervous systems for response• Muscles allow for movement• Sexual reproduction – individuals (male and female)• Diseases – trichinosis, elephantiasis,
  5. 5. Annelids• Segmented bodies, complex organ systems that are unique due to segmented body plan• Filter feeders and predators• Closed circulatory system – dorsal vessel moves toward head and ventral moves toward tail• Aquatic breathe through gills, land through skin
  6. 6. Cont.• Removes waste from digestion through anus and cellular waste by nephridia• Have a well developed nervous system and fundamental brain to respond to stimuli• Have two major groups of body muscles that function as part of the hydrostatic skeleton for movement – longitudinal head to end (fatter or short) circular around body contract to make worm longer and thinner
  7. 7. Cont.• Hermaphrodites: have both sperm and eggs• 3 Types of Annelids• Oligochaetes• Leeches• Polychaetes
  8. 8. Mollusks• Soft-bodied animals that usually have an internal or external shell• Have four parts: foot, mantle, shell, visceral mass• Herbivores, carnivores, filter feeders, detritivores or parasites• Breathe through gills or across skin• Open or closed circulatory systems
  9. 9. Cont.• Cells release Nitrogen containing waste into the blood in the form of NH3 and removed by nephridia• Simple organisms (clams) have nervous systems made of ganglia, more complex organisms have (octopi) have very complex nervous systems and a highly developed brain
  10. 10. Cont.• Movement depends on species – snails secrete mucus and move with a rippling motion along – octopus use jet propulsion• Reproduction depends on species – some are hermaphrodites, other release egg and sperm by external fertilization• 3 types of mollusks –• Gastropod, bivalves, cephalopods
  11. 11. Arthropods• Insects, crabs, centipedes and spiders• Segmented body, tough exoskeleton and jointed appendages• Natural selection and other process has led to fewer body segments, highly specialized appendages for feeding, movement and other functions
  12. 12. Cont.• Herbivores, carnivores and omnivores• Breathe oxygen through specialized organs (tracheal tubes, book lungs)• Open circulatory system• Excretes waste through specialized organs• Well developed nervous system, ALL have a brain
  13. 13. Cont.• Movement provided by well developed muscles controlled by nervous system• Internal or external reproduction depending on the species• growth - outgrow exoskeleton by molting• Classified by number and structure of segments and appendages (specifically mouth parts)
  14. 14. Cont.• Crustaceans, spiders (and relatives), insects (relatives)
  15. 15. Insects• Body divided into 3 parts – head, thorax (3 pairs of legs attached), abdomen• Use sense organs to respond to stimuli compound eyes, chemical receptors, sensory hairs, well developed ears (beyond human range)• Mouth part used for feeding• Movement uses legs (walking, jumping, holding prey)
  16. 16. Cont.• Metamorphosis – complete (look nothing like parent) or incomplete (look a lot like parent)• Complex social order system called societies using a “language” to communicate information
  17. 17. Echinoderms• Spiny skin, internal skeleton, water vascular system, suction structures, exhibit five-part radial symmetry (star fish)• Water vascular system carries out essential body functions respiration, circulation and movement• Sea urchins, sea cucumbers, sea stars• Crown of thorns – major threat to coral
  18. 18. Evolution• 575 to 543 million years old – Ediacaran• Soft bodied with little specialization• By Cambrian (544 mil yrs) period many had formed shells, skeletons and other hard body parts
  19. 19. Evolutionary Trends• Specialized cells, tissues, organs• Body symmetry - All invertebrates except sponges exhibit some type of body symmetry• Cephalization – respond to environment in more sophisticated ways• Segmentation – increased body size• Complex animal phyla have a true coelom that is lined completely with tissue derived from mesoderm
  20. 20. Form and Function• Digestion: Intercellular (digested inside cell) or extracellular (in digestive cavity then absorbed) design• Respiration: large moist surface area in contact with air and water where diffusion can take place• Circulation: move blood through one or more hearts and an open or closed circulator system
  21. 21. Cont.• Excretory: removal of ammonia aquatic- diffusion / terrestrial ammonia is converted to urea (less toxic) released through excretory pores• Response: 3 trends – centralization (simplest nervous system), cephalization (brain), specialization (sense organs)
  22. 22. Cont.• Movement and support: 3 main kinds of skeletal systems – hydrostatic (fluid filled), exoskeleton (outside body), endoskeletons (inside body)• Reproduction: sexually and asexually depending on organism – external (outside body) internal (inside body)

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