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Phylum Mollusca Class: Gastropoda   Class: Bivalvia
Characteristics of Mollusca• Protosome characteristics• Coelom surrounds heart• Open circulatory system (except cephalopods)
Class GastropodaSnails, Limpets and Slugs
Gastropoda• Planning on being rich  and famous?• Wining and dining at the  most expensive  restaurants?• Romantic trips to...
General Body Plan:             Gastropod• 1. Head foot• Head: sensory  nerves, mouth   – Anterior: near the     head/mouth...
That slimy foot…• Snail Slime:   – Suction power: travel up     and down trees   – Escape: Emit a nasty     tasting slime ...
General Body Plan:          Gastropod• 2. Visceral Mass  – Organs of    digestion  – Circulation  – Reproduction  – Excret...
General Body Plan:              Gastropod• Mantle (shell)   – Attached to visceral     mass       • Encloses most of the  ...
Respiration• One Gill in mantle  cavity   – Oxygen is taken in   – Diffused through the cells• Open Circulatory  System   ...
General Body Plan: Mollusca• Radula: Scraping  mouth   – Chitinous belt & curved     teeth      • Covers fleshy tongue    ...
• How do mollusks exchange gasses  – Filter air through their gills• Where are these gills located?  – The mantel• What is...
Gastropoda• Marine, Freshwater, Terrestrial• Signifying feature: Torsion
Torsion• Benefits  – Head enters first:    protection  – Operculum seals    opening to prevent    drying out  – Allows cle...
Torsion
Reproduction• Monoecious: can be  whatever sex they  want!  – Internal cross    fertilization  – One snail acts as    fema...
CFU• What is Torsion?  – The 180 degree twisting of internal organs    in snails• How is Torsion adaptive?  – Pulls head i...
Class BivalviaClams, Oysters, Mussles, Scallop               s
Bivalvia!• Edible• Commercial value:  Form Pearls• Valuable in removing  bacteria from polluted  water!   – Rely on water ...
Structure• Two halves of a shell:  Valves    – Adductor muscles hold      valves shut•   Visceral Mass•   Mantel Cavity•  ...
Foot• Most mollusks have  foot that can be  used differently  – Attach mollusk to    surface  – Act as a lure to    attrac...
Respiratory System• Respiration: Cilia in  gills move water into  mantel cavity  – Water tubes    exchange water to    blo...
Digestive System• Food comes in  through gills  – Sorted  – Digested  – Waste forcibly    pushed out of mantel    cavity b...
Human Interaction• Many, many  mollusks are  threatened or  endangered  –   Over harvesting  –   Pollution  –   Loss of ha...
CFU• What is the technical term for the two halves  of the shell?   – Valves• What structure filters water in and out of t...
Get ready for dissection!
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Mollusks%20bivalves%3agastro[1]

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Mollusks%20bivalves%3agastro[1]

  1. 1. Phylum Mollusca Class: Gastropoda Class: Bivalvia
  2. 2. Characteristics of Mollusca• Protosome characteristics• Coelom surrounds heart• Open circulatory system (except cephalopods)
  3. 3. Class GastropodaSnails, Limpets and Slugs
  4. 4. Gastropoda• Planning on being rich and famous?• Wining and dining at the most expensive restaurants?• Romantic trips to Paris?• Ever wonder what Ceaser munched on after long hard days ruling the roman empire?• Than you should be familiar with ESCARGOT!!!!
  5. 5. General Body Plan: Gastropod• 1. Head foot• Head: sensory nerves, mouth – Anterior: near the head/mouth• Foot: attachment and locomotion – Posterior: near the anus – Flattened w Cilia: locomotion
  6. 6. That slimy foot…• Snail Slime: – Suction power: travel up and down trees – Escape: Emit a nasty tasting slime when threatened – Movement: Allows them to easily squeeze through tight spaces – Water Retention• Ecological Roles: – Skin regenerating – used in skin beauty products
  7. 7. General Body Plan: Gastropod• 2. Visceral Mass – Organs of digestion – Circulation – Reproduction – Excretion – Dorsal to the head foot
  8. 8. General Body Plan: Gastropod• Mantle (shell) – Attached to visceral mass • Encloses most of the body – Protection• Mantle Cavity: – Gas exchange – Elimination of digestive wastes – Release of reproductive products
  9. 9. 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
  10. 10. General Body Plan: Mollusca• Radula: Scraping mouth – Chitinous belt & curved teeth • Covers fleshy tongue • Muscles move it back and forth • Conveyor belt• Digestion – Scrape algae – Enzymes break down food in stomach
  11. 11. • How do mollusks exchange gasses – Filter air through their gills• Where are these gills located? – The mantel• What is the structure called that scrapes up food? – A Radula• All mollusks have: – A visceral Mass – A head foot – A mantel
  12. 12. Gastropoda• Marine, Freshwater, Terrestrial• Signifying feature: Torsion
  13. 13. 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
  14. 14. Torsion
  15. 15. 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
  16. 16. CFU• What is Torsion? – The 180 degree twisting of internal organs in snails• How is Torsion adaptive? – Pulls head in first, seals opening, locates all sensory nerves in the front
  17. 17. Class BivalviaClams, Oysters, Mussles, Scallop s
  18. 18. Bivalvia!• 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
  19. 19. 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
  20. 20. Foot• Most mollusks have foot that can be used differently – Attach mollusk to surface – Act as a lure to attract prey – Surround organs for safety
  21. 21. Respiratory System• Respiration: Cilia in gills move water into mantel cavity – Water tubes exchange water to blood through diffusion – Water exits bivalve
  22. 22. Digestive System• Food comes in through gills – Sorted – Digested – Waste forcibly pushed out of mantel cavity by valves shutting quickly
  23. 23. Human Interaction• Many, many mollusks are threatened or endangered – Over harvesting – Pollution – Loss of habitat – Loss of water currents
  24. 24. CFU• What is the technical term for the two halves of the shell? – Valves• What structure filters water in and out of the shell – Siphon• What is the function of the foot – Attach mollusk to substrate, act as lure• Why are bivalves important to humans? – Pearls, food source, pollution filter• How are humans affecting bivalves? – Over harvesting, pollution, loss of current
  25. 25. Get ready for dissection!

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