1. http://www.youtube.com/watch?v=Gg57Id z7Bs4
q_344

2. General Name means soft body
this is one of the largest animal phyla, besides Arthropoda
There are nearly 75,000 species and some 35,000 fossil species
Very diverse group (snails, clams, octopus)
Range from simple organisms to some of the most complex invertebrates

3. Hawaiian Bobtail Squid

5. Blue Ringed Octopus

8. Ecological Relationship
Habitats: from tropics to polar region
ponds, lakes, streams, surf, ocean depths, etc
Most live in the sea
Include herbivores, carnivores, and filter feeders

9. Economic Importance many are food for humans
produce pearls (most from Eastern Asia)
Some molluscs are destructive (Great Lakes, Snails and Slugs in gardens)

14. Form and Function Body Plan –
consist of head-foot portion (cephalopod) and a visceral mass (nervous system)
head-foot portion – contains feeding, cephalic sensory, and locomotion organs
visceral mass – contains digestive, circulatory, respiratory, and reproductive organs

16. Form and Function Body Plan –
two folds of skin make up a protective “mantle”
mantle houses the lungs and secretes a shell in many species

17. Form and Function Head-foot –
many have a well developed head containing sensory organs
range from simple to complex eyes
Foot is used for locomotion

18. Form and Function Head-foot –
Unique structure inside mouth called “radula”
It is a tonguelike found in all molluscs except bivalves (shell fish)
Has rows of tiny teeth that point backward
It has about 250,000 teeth
When protruded, it can scrape, pierce, tear, or cut food material
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22. Form and Function Head-foot –
Foot can be adapted for locomotion, attachment, or a combination of functions
Some modifications include – “hatchet foot” of bivalves, funnel for jet propulsion in squids and octopi

23. Form and Function Visceral Mass – (mantle and mantle cavity)
mantle – the outside of the skin extending from the visceral hump that runs down each side of the body, protecting soft parts and creating a space

24. Form and Function Visceral Mass – (mantle and mantle cavity)
mantle cavity – houses respiratory organs
products from digestive, excretory, and reproduction systems empty into the mantle cavity
in aquatic species, surface cilia create water currents that continually flush out waste

26. Form and Function Visceral Mass –
Shell (when present) typically has three layers
outer layer
Composed of a protein called “conchiolin”
Growth only occurs at the edge of the shell
middle layer
Composed of densely packed prisms of calcium carbonate in a protein matrix
Inner layer
Composed of calcium carbonate sheets laid down over a thin protein matrix
This layer is continuously secreted by mantle surface, so it becomes thicker during the animals life
Calcium for the shell comes from environmental water, soil, or food

27. a. Outer layer b1. middle layer b2. Inner layer

28. Form and Function Internal Structure and Function –
there is an open circulatory system
pumping heart
blood vessels
blood sinuses
closed circulatory system

30. Form and Function Internal Structure and Function –
Digestive tract is highly specialized according to feeding habits
Most have a pair of kidneys
Ducts of kidneys in many forms serve to discharge eggs and sperm

31. Form and Function Internal Structure and Function –
Nervous System consists of several pairs of ganglia (nerve cells) with connected nerve cords
Most molluscs are dioecious
Some are hermaphroditic

32. Mating Leopard Slugs

33. Class Polyplacophora: Chitons
are somewhat flattened and have a surface that bears eight plates, or valves
name means “bearing many plates”
most are between 2 and 5 cm
commonly occur on rocky surfaces in intertidal regions
if detached, they can roll up like an Armadillo for protection
Sexes are separate

40. Class Gastropoda (gastro – stomach, podos – foot)
By far the largest and most diverse class
Contains about 40,000 living species
Includes snails, limpets, slugs, whelks, conchs, periwinkles, sea slugs, sea hares, sea butterflies, etc.
Often sluggish, sedentary animals
Because of heavy shells and slow locomotion organs

41. Snails

42. Snails

43. Limpets (Owl Limpet)

44. Limpets

45. Slugs

46. Whelks

47. Whelks (Lightening)

48. Conchs

49. Conchs

50. Conchs

51. Periwinkles

52. Periwinkles

53. Sea slugs

54. Sea slugs

55. Sea slugs

56. Frosted Sea Slug

57. Sea hares

58. Sea hare

59. Sea hare

60. Sea butterflies

61. Class Gastropoda
Basically bilaterally symmetrical, but because of “torsion,” the visceral mass is asymmetrical
Torsion – a twisting process that occurs during development

63. Class Gastropoda Three subclasses – Prosobranchia (largest)
Almost all marine
Periwinkles, limpets, whelks, conchs, abalones, slipper shells, oyster borers, rock shells, cowries
Opisthobranchia
Sea slugs, sea hares, nudibranchs, canoe shells
Pulmonata
Mostly land and freshwater snails and slugs
Usually have two pairs of tentacles

64. Nudibranchs

65. Nudibranchs

66. Class Bivalvia (two-shelled)
Includes mussels, clams, scallops, oysters, shipworms
Most are sedentary
Unlike gastropods they have no head, radula, and little cephalization

67. Class Bivalvia
Most are marine, but many live in brackish water and in stream, ponds, and lakes
Their two shells (valves) are held together by a “hinge ligament”
“Adductor muscles” work in opposition to the hinge ligament and draw the valves together
Zebra mussels

69. Zebra mussels (Lake Mead)

70. Preventing Mussels in IdahoMk s

71. Class Cephalopoda most complex species
include squids, octopuses, nautiluses, cuttlefishes
All are marine
All are active predators
Have an odd body plan
Develops as the embryonic head and foot become indistinguishable
The ring around the mouth bears arms and tentacles

72. Class Cephalopoda
Range from 2 to 3 cm to 13 meters

73. Giant Squid

74. Slash marks from Giant Squid

75. The Search for the Giant Squid

76. Class Cephalopoda
Most have special pigment cells called “chromatophores” in their skin
By expanding and contracting, they produce color change
Some color change are for protection to match the background
Most change is behavioral, associated with alarm or courtship
Many deep-sea squid are bioluminescent
When the animal is alarmed, it releases a cloud of ink through the anus to form a “smokescreen” to confuse an enemy

77. Squid

78. Mimic Octopus and others
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79. Octopuses

80. Octopuses

81. Octopuses

82. Blue Ringed Octopus The most venous octopus.
This small mollusc lives in warm, shallow reefs off the coast of Australia, new Guinea, Indonesia and the Philippines. 
It has a life span of about one and a half years.

83. Blue Ringed Octopus
It is said that the venom of this octopus could kill 26 adults in just a few minutes.
There is no antivenin for treatment.
Fortunately, these octopuses do not attack humans.
Injury typically occurs when a blue-ringed octopus is stepped on or picked up.

84. Nautiluses

85. Nautiluses

86. Nautiluses

87. Cuttlefishes

88. Cuttlefishes

89. Cuttlefishes