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Bivalves and Cephalopods

Bivalves and Cephalopods. About one thousand species live in fresh water. Zebra Mussel Zebras on native clams (Unionidae). Best understood in the context of their largely sedentary adult life style. umbo. ctenidium. Adductor muscle. Right valve. Labial palps.

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Bivalves and Cephalopods

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  1. Bivalves and Cephalopods

  2. About one thousand species live in fresh water Zebra Mussel Zebras on native clams (Unionidae)

  3. Best understood in the context of their largely sedentary adult life style

  4. umbo ctenidium Adductor muscle Right valve Labial palps Excurrent Incurrent siphons mouth Foot Mantle edge

  5. Two principal types, distinguished by their Ctenidia and mode of feeding Class Bivalvia Protobranchia Llamellibranchia Filibranchia Eullamellibranchia

  6. Ctenidia of Bivalves are modified for feeding except in one group: the Protobranchs

  7. In most bivalves ctenidia are sheet-like with high S.A., and are used for feeding

  8. Captured particles are moved to a ciliated ventral groove and then as a mucus strand to the mouth. http://www.biology.ualberta.ca/facilities/multimedia/index.php?Page=252

  9. Summary of Water Flow and Feeding http://web.uconn.edu/jevanward/video/musselsum.MPG The sheetlike, arrangement of ctenidia in most bivalves is known as the Llamellibranch condition

  10. There are two basic type of Llamellibranch ctenidia in bivalves Filibranch (in mussels) Eullamellibranch (most clams)

  11. Living Cephalopods Squid Nautilus Cuttlefish Octopods --The class as a whole is adapted for swimming, suspended in the water by buoyancy mechanisms. -- allare carnivores, occupying the same niche as fishes

  12. Architeuthys Giant squid up to 20 m long Mesonycheteuthis Colossal squid up to 14 m major prey item of sperm whales Dosidicus Humboldt squid, smaller but numerous (2 m) and comes to surface to feed

  13. Ammonites Largest is 3 m in diameter

  14. Sub Class Nautiloidea 5-6 species remain from diversity in geologic past Live in the last chamber of a multi-chambered shell Move by forcing water through a siphon.

  15. Sub Class Nautiloidea How does a Nautilus adjust and maintain its buoyancy in water?

  16. Cuttles, Squids and Octopuses • tendency is reduction of shell. • compensated for by selective ionic control; accumulate ammonium • other adaptations to shell loss and life style

  17. cuttle chameleons of the sea most specialized, agile and cryptic octopus

  18. Specifically, compensation takes the following forms: Stealth and other defenses Acute sensory structures Speed Cunning

  19. A. Stealth and other defenses Ink Sack : ink with melanin and mucus also dopamine, L-DOPA, tyrosinase Pseudomorphs

  20. A. Stealth and other defenses Chromatophores: each cell contains a different pigment which may be red, orange, brown, black, yellow or blue

  21. Cephalopod Chromatophore Black, brown, orange or yellow colors Also iridiophore reflective cells Most cephalopods are completely colorblind neurophilosophy.files.wordpress.com

  22. B. Acute sensory structures -- Vision -- Lateral line analogs

  23. C. Speed Rival fish in ability to swim, attaining burst speeds of 5-10 m second sustained for short distances at speeds of up to 40 km hr. Burst speed is achieved by jet propulsion More gradual swimming is fin undulation

  24. C. Speed : complex nerve control of locomotion Assures synchronized contraction of mantle muscles

  25. C. Speed : circulatory system Hearts Requires a closed, elaborate circulatory system

  26. D. Cunning -- Relative to body size, the brain is larger than that of most fish

  27. Experiments with Octopus vulgaris show their ability to learn. They learn to choose colors not associated with shock. Observers choose properly colored objects after watching demonstrators

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