Phylum Mollusca Class: Gastropoda   Class: BivalviaClass: Cephalopoda
Class GastropodaSnails, Limpets and Slugs
General Body Plan:                    Gastropod• Characteristics   – 1. Head foot      • Head: sensory nerves, mouth      ...
General Body Plan:         Gastropod2. Visceral Mass – Organs of   digestion – Circulation – Reproduction – Excretion – Do...
General Body Plan:              Gastropod3. Mantle (shell)   – Attached to visceral     mass       • Encloses most of the ...
That slimy foot…• Snail Slime:   – Escape   – Movement   – Water Retention• Ecological Roles:   – Skin regenerating   – us...
Respiration• One Gill in mantle  cavity   – Oxygen is taken in   – Diffused through the cells• Open Circulatory  System   ...
• Digestion   – Scrape algae   – Enzymes break down     food in stomach• Radula: Scraping  mouth   – Chitinous belt & curv...
Torsion• Benefits  – Head enters first:    protection  – Operculum seals    opening to prevent    drying out  – Allows cle...
Reproduction• Monoecious: can be  whatever sex they  want!  – Internal cross    fertilization  – One snail acts as    fema...
Class BivalviaClams, Oysters, Mussles,        Scallops
Structure• Two halves of a shell:  Valves    – Adductor muscles hold      valves shut•   Visceral Mass•   Mantel Cavity•  ...
Foot– Attach mollusk to  surface– Act as a lure to  attract prey– Surround organs for  safety
Ecological Roles• Edible• Commercial value:  Form Pearls• Valuable in removing  bacteria from polluted  water!   – Rely on...
Digestive System• Food comes in  through gills  – Sorted  – Digested  – Waste forcibly    pushed out of mantle    cavity b...
Respiratory System• Respiration: Cilia in  gills move water into  mantel cavity  – Water tubes    exchange water to    blo...
Human Interaction• Many, many  mollusks are  threatened or  endangered  –   Over harvesting  –   Pollution  –   Loss of ha...
Mollusks: Cephalopods  Octopus, Squid, Cuttlefish
Physical Characteristics• Anterior   – Tentacles and jet     propulsion• Mantle (Shell)   – Nautilus: only     cephalopod ...
Locomotion• Jet like propulsion  out of mantle   – Squid: uses it for     catching prey      • Up to 25 mph!   – Octopus: ...
ECOLOGICAL ROLE• Fierce Predators  – Large brains  – Complex sensory structures  – Rapid locomotion  – Grasping tentacles•...
Digestion• Enzymes digest  food in stomach  – Moves to anus  – Expelled during    jet propulsion
Giant Squid Dissection• http://www.youtube.com/watch?v=d83n  SFEoz2A&safety_mode=true&persist_s  afety_mode=1&safe=active
Predator Adaptations• Locate prey by sight• capture prey w  tentacles/ suction cups   – Tentacles reinforced w     protein...
Predator Adaptations• Chromatophores   – Cells that can change colors• Tiny muscles contract or expand  and chromatophores...
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C hapter 9 mollusks

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C hapter 9 mollusks

  1. 1. Phylum Mollusca Class: Gastropoda Class: BivalviaClass: Cephalopoda
  2. 2. Class GastropodaSnails, Limpets and Slugs
  3. 3. General Body Plan: Gastropod• Characteristics – 1. Head foot • Head: sensory nerves, mouth • Foot: attachment and locomotion
  4. 4. General Body Plan: Gastropod2. Visceral Mass – Organs of digestion – Circulation – Reproduction – Excretion – Dorsal to the head foot
  5. 5. General Body Plan: Gastropod3. Mantle (shell) – Attached to visceral mass • Encloses most of the body – Protection4. Mantle Cavity: – Gas exchange – Elimination of digestive wastes – Release of reproductive products
  6. 6. That slimy foot…• Snail Slime: – Escape – Movement – Water Retention• Ecological Roles: – Skin regenerating – used in skin beauty products• http://www.youtube.com/watc h?v=JhRwcPRy6l4&safety_ mode=true&persist_safety_ mode=1&safe=active
  7. 7. Respiration• One Gill in mantle cavity – Oxygen is taken in – Diffused through the cells• Open Circulatory System – Pushes blood in to expand – Pulls it out to contract
  8. 8. • Digestion – Scrape algae – Enzymes break down food in stomach• Radula: Scraping mouth – Chitinous belt & curved teeth • Covers fleshy tongue • Muscles move it back and forth • Conveyor belt
  9. 9. Torsion• Benefits – Head enters first: protection – Operculum seals opening to prevent drying out – Allows clean water to enter mantle cavity – Makes snail more sensitive to stimuli coming from the front
  10. 10. Reproduction• Monoecious: can be whatever sex they want! – Internal cross fertilization – One snail acts as female one acts as male – Deposit eggs in gelationous strings
  11. 11. Class BivalviaClams, Oysters, Mussles, Scallops
  12. 12. Structure• Two halves of a shell: Valves – Adductor muscles hold valves shut• Visceral Mass• Mantel Cavity• Gills• Cilia• Siphon: – filters water in and out of shell
  13. 13. Foot– Attach mollusk to surface– Act as a lure to attract prey– Surround organs for safety
  14. 14. Ecological Roles• Edible• Commercial value: Form Pearls• Valuable in removing bacteria from polluted water! – Rely on water currents to get food – Filter in nutrients, filter out clean water• Valuable food source: humans, raccoons, otters, birds
  15. 15. Digestive System• Food comes in through gills – Sorted – Digested – Waste forcibly pushed out of mantle cavity by valves shutting quickly
  16. 16. Respiratory System• Respiration: Cilia in gills move water into mantel cavity – Water tubes exchange water to blood through diffusion – Water exits bivalve
  17. 17. Human Interaction• Many, many mollusks are threatened or endangered – Over harvesting – Pollution – Loss of habitat – Loss of water currents
  18. 18. Mollusks: Cephalopods Octopus, Squid, Cuttlefish
  19. 19. Physical Characteristics• Anterior – Tentacles and jet propulsion• Mantle (Shell) – Nautilus: only cephalopod w external shell • Fills it with gasses to help w buoyancy – Squid: internal shell, helps with structure – Octopus: NO SHELL
  20. 20. Locomotion• Jet like propulsion out of mantle – Squid: uses it for catching prey • Up to 25 mph! – Octopus: escape method
  21. 21. ECOLOGICAL ROLE• Fierce Predators – Large brains – Complex sensory structures – Rapid locomotion – Grasping tentacles• http://www.youtube.com/watch?v=p9A- oxUMAy8&safety_mode=true&persist_saf ety_mode=1&safe=active
  22. 22. Digestion• Enzymes digest food in stomach – Moves to anus – Expelled during jet propulsion
  23. 23. Giant Squid Dissection• http://www.youtube.com/watch?v=d83n SFEoz2A&safety_mode=true&persist_s afety_mode=1&safe=active
  24. 24. Predator Adaptations• Locate prey by sight• capture prey w tentacles/ suction cups – Tentacles reinforced w protein• Eat using a radula – Cuttlefish: small invertebrates – Octopus: • Nocturnal: snails, fish, crustations
  25. 25. Predator Adaptations• Chromatophores – Cells that can change colors• Tiny muscles contract or expand and chromatophores quickly change color – Alarm response – Defensive – Blend in w environment – Courtship – Bioluminescence• http://www.youtube.com/watch?v=t- LTWFnGmeg&feature=related&safe ty_mode=true&persist_safety_mod e=1&safe=active

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