1. Mollusks

2. Kingdom: Animalia Phylum: Mollusca Classes:
Cephalopoda-octopuses, squids, cuttlefish
Gastropoda- snails, nudibranchs
Bivalvia-clams, mussels, oysters
Polyplacophora- chitons

3. Mollusk Song http://www.youtube.com/watch?v=0a7j5prL8hc
Mollusk puppet show
Mollusk beauty slide show

4. Invertebrates Molluscs Characteristics of Phylum:
More than 200,000 species
Name means "soft body"
Basic body plan – head, muscular foot and visceral mass in most species
Mantle- secretes shell, waste disposal, sensory reception, respiration
Many have a shell of calcium carbonate
Radula for grazing is unique to this group
Some are deposit feeders, others carnivores, some use radula for scraping algae, encrusting animals, etc. off substrates
Well developed nervous system
Open circulatory system
Complete digestive system
Trochophore larvae develops into a planktonic veliger larvae complete with shell (miniature version of adult)

5. Body plan Study figure 7.20 page 127
Head/foot: head is mouth and sensory structures
Visceral mass: above head-food. Contains heart and organs for digestion, excretion and reproduction. Covering this is a layer of epidermis called the mantle

6. Respiration and gas exchange
Mantle
Secretes shells
Protects organism but also reduces surface area for gas exchange
Organisms have gills
Provide large surface area with rich blood supply
Allows for diffusion to happen easily
Gills located in mantle cavity (hollow space under the shell)

7. Mollusk Gills

8. Circulatory system Open system Hemolymph- circulatory fluid
Does not remain within blood vessels
Once filled with oxygen, it travels to heart and then is pumped throughout spaces and tissues

9. Nervous system Ganglia
Clusters of nerve cells located in head-foot and connected by two long nerve cords to visceral mass

10. Digestive system Radula-
Flexible, tongue like strip of tissue covered with tough, abrasive teeth that point backward
Radula can cut, scrape, drill, and harpoon

11. Mollusk Reproduction

12. Invertebrates Types of Molluscs: Chitons pg 132 800 species All marine
Not coiled like snails
Dorsal shell of 8 plates.
Ventral muscular foot.
Ventral mouth with radula
Mostly found in shallow water, coastal environments of hard substrate
Many graze on algae & small animals in marine intertidal zone (area between high and low tides)
Chitons have separate sexes, fertilization is external
Animals which prey on chitons include humans, seagulls, seastars, crabs, lobster, fish

13. After a chiton dies, the individual valves which make up the eight-part shell come apart because the girdle is no longer holding them together, and then the plates sometimes wash up in beach drift. The individual shell plates from a chiton are sometimes known as "butterfly shells" because of their shape.

14. The largest chiton (up to 33 cm in length) is the brick-red gumboot chiton.

15. Chitons

18. Chiton video

19. Invertebrates Types of Molluscs:
Bivalves (body plan and representatives shown in Fig and Fig. 7.24, pg )
Clams, Oysters, Scallops, Mussels, etc.
Two shells or “valves”
Oldest part of the shell is called the umbo
Shell grows out from the umbo in concentric rings
No head present but still considered bilateral
No radula present. Filter feeders
Adductor muscles secure valves together. Closes shell.
Muscular foot used for burrowing in bottom and other locomotion. Otherwise sessile
Water circulated with siphons
Gills for respiration & food gathering (filter feeding). Ctenidia
Some species burrow, others attach to hard substrates via byssal threads, or grow attached to each other

21. Most bivalves have a pair of large gills which are located in their mantle cavity. The gills enable them to extract oxygen from the water (to breathe) and to capture food. Water is drawn into the mantle cavity and washes through the gills. In species that burrow, a long siphon is extended to the surface to take in water. Mucus on the gills helps capture food and cilia transfer the food particles to the mouth. Once in the mouth, food passes into the stomach to be digested.

22. Bivalves have a mouth, heart, intestine, gills, stomach and siphon but have no head, radula or jaws. They have an abductor muscle that, when contracted, holds the two halves of the shell closed. Bivalves have a muscular foot, which in many species such as clams, is used to anchor their body to the substrate or dig down into the sand

23. The smallest living bivalve is one of the Nut Clams, Condylonucula maya. An adult Condylonucula, measures only 500 microns — less than 2 one-hundredths of an inch — about half a millimeter. The largest living bivalve is the Giant Clam, Tridacna gigas. This gentle giant can grow almost 5 feet in length (up to 1½ meters).

24. Nut clam

25. Giant clam

26. Monster of the Deep: Giant Clams
National Geographic

27. clams Bivalves that live in mud or sand
Mantle cavity is sealed except for pair of hollow, fleshy tubes called siphons
Incurrent siphon- water enters
Excurrent siphon- water leaves
Clams have separate sexes

28. Clam eating salt off table

29. Dirty Jobs: Clam Shucker 6:08

30. Clam dissection

31. oysters

32. Oyster journal Research pearl formation
Although it is possible for food oysters to produce pearls, they should not be confused with actual pearl oysters, which are from a different family of bivalves

33. Oysters and water quality
Oysters act as a natural filtration system; they filter silt and contaminants from the water. A single oyster can filter up to 50 gallons of water per day! A large, healthy oyster population filters large volumes of water and thereby improves local water quality and clarity.

34. Because oysters filter their food from the water in which they live, if that water becomes contaminated they can concentrate harmful toxins in their meat.
PSP is a biotoxin produced by the naturally-occurring dinoflagellate Alexandrium catenella. When consumed via contaminated shellfish, the biotoxin can produce symptoms within an hour or two, ranging from tingling or numbness of the lips to speech impairment and interference with breathing and moving. There is no known antidote and death may occur in some extreme cases.

35. Oyster reproduction
They reproduce when the water warms by broadcast spawning, and will change gender once or more during their lifetime
They change their gender at least once in their lifetimes. All oysters start off as male, but most change permanently to female by the time they are a year old. Their reproductive organs produce both sperm and eggs, and they can change gender at will. It is technically possible, therefore, for an oyster to fertilize its own eggs

36. Gastropods Let’s find out!!!!! Can you name a gastropod?
What does “gastropod” mean?
Do all gastropods have shells?
Are all gastropods marine?
Let’s find out!!!!!

37. Invertebrates Types of Molluscs: Gastropods
Largest class of molluscs, about 75,000 species
Snails, limpets, abalone, conchs, slugs (figure 7.22)
Name means "belly-footed"
Coiled shell on most species. Twists in a clockwise direction
No shell on sea slugs (nudibranchs)
Radula for grazing on plants in most, some are deposit feeders
Some species are carnivorous and use radula for prey capture (some will even prey on members of the same species)
Only marine group which have colonized terresterial habitats

38. Visceral organs show well organized features, which include a nervous system, a heart and circulatory system, a digestive system, excretory system, and a reproductive system
Both sexual and hermaphroditic reproduction are found among the various species and families

39. operculum Hardened structure on the surface of their foot
Is it like a shoe??????
No!
Serves as a lid that protects the gastropod when it retracts its body within the shell
Operculum seals the shell opening to prevent injury from predators

41. torsion What is torsion????? A type of torture?
Like a torsion tensor in differential geometery?
NO………………..
It’s so much more exciting than that!!!!

42. torsion During development torsion occurs.
Twisting of body (not shell) along its head to tail axis
Twisting means that the head is between 90 and 180 degrees offset relative to their foot
Start out bilateral then by adulthood they are asymmetrical
The adult ends up configured in such a way that its body and internal organs are twisted and the mantle and mantle cavity are above its head

43. torsion

44. 6 groups Patellogastropoda Vetigastropoda Cocculiniformia Neritimorpha
Caenogastropoda
Heterobranchia- most diverse

45. NO………..
You don’t have to memorize those names
You’re welcome…..

47. Ever seen a whelk?????

48. whelks

49. whelk
whelk, any marine snail having a similar shell. Some are incorrectly called conchs. The sturdy shell is elongated and has a wide aperture in the first whorl. They feed on other mollusks through its long proboscis; some also kill fishes and crustaceans caught in commercial traps. Whelks occur worldwide

50. ScienceDaily: Male Welks

51. periwinkles
A Periwinkle is a small sea animal with a thick spiral shell
The common periwinkle is a popular food in Europe

52. Snails can Fly!

53. limpets
Limpets cling tightly to a rock (using the muscular foot). During the day, limpets move around by rippling the muscles of the foot in a wave-like fashion, looking for food. They return to the same place on their rock each night. No one knows exactly how they find their way back to the same spot each time.

54. limpets

55. Question……..
Does Conch have bone????
Ask the experts

56. Conch

57. Listening to conch
Why can you hear the ocean in a seashell? You can hear the sound of the "ocean" not just with seashells, but also with a coffee cup or glass, or even by cupping your hand loosely over your ear. The usual explanation is that the seashell amplifies the sound of blood moving in your ear. Two pieces of evidence suggest that this is not correct. First, the sound is the same before and right after exercise (try running up and down stairs or doing jumping jacks), but it should be louder after you exercise since blood would be moving faster. Second, the sound is not drowned out by loud noise such as that heard next to a window mounted air conditioner. A better explanation is that the shell (or glass) acts as a resonating chamber, bouncing surrounding sounds back and forth, jumbling and amplifying them. This means that you should be able to hear the "ocean" better in a noisy room than in a very quiet one.

58. Playing a conch

59. Conch
The term 'conch' (pronounced "konk") is used to describe over 60 species of sea snails which have a medium- to large-sized shell. In many species, the shell is elaborate and colorful. Probably the most well-known species is the queen conch, which is the image that might come to mind of a sea shell. This shell is often sold as a souvenir, and it's said you can hear the sea if you put a conch shell to your ear.

60. Live conch video

61. “The Conch Republic”

62. “What is conch” from a chef

63. nudibranch

64. nudibranch

65. Gastropoda videos Snails http://www.youtube.com/watch?v=DTMaqy39go0
Nudibranchs
Gastropods

66. Cephalopods

67. Name a cephalopod!
Name a distinguishing feature of a cephalopod

69. examples

70. Let’s amuse ourselves with a little pre test

71. Invertebrates Types of Molluscs: Cephalopods Name means “head foot”
Squid, Octopus, Nautilus, & Cuttlefish
650 species – all marine
Foot modified into 8-10 arms or tentacles and a siphon
Fast swimming predators due to water jet propulsion
Well developed eyes
Thick mantle covers the body. No shell. Remnant inside squid is called the “pen”
Use beak-like jaws and radula to crush or rip prey. Sometimes with poison glands. Radula is behind the beak
Adapted tentacles
Ink sac- expels ink out of siphon to distract predators and allow for escape

72. Invertebrates Shell internal or absent in most
Most advanced invertebrates
In octopus, the shell has been replaced by a beak-like jaw which can deliver a powerful bite
Some octopus have toxic bites
Ink sac is also seen in octopus to allow escape from predators
A stiff internal “pen” is seen in squid is a modified shell

73. What is the plural of octopus?
Octopuses. Octopi is wrong, although generally accepted these days.

74. Members of the order Nautiloidea have more than 90 tentacles; members of orders Sepioidea and Teuthoidea have eight arms and two tentacles; and members of orders Ocotopoidea and Vampyromorpha have eight arms

75. hearts How many hearts does the octopus have? 3
Why do they have 3 hearts? Basically, when you have 8 legs you need extra blood flow, thus having more than one heart is necessary.  Octopuses have three hearts. Two pump blood through each of the two gills, while the third pumps blood through the body.

76. brain
Only mammals and birds have more complex brains than that of the octopus. Octopuses have excellent memories, have played with objects, unscrewed jars to get to the crab inside. Their brain has folds, another indication of complexity. They can be left-eyed or right-eyed like in humans with their hand preferences.

77. beak

78. beak
The beak is the only hard part of an octopus and squid’s body. It is located on the lower side of the body. In the mouth is a radula, a toothed tongue for rasping. The beak is made of the same material, keratin, that a bird’s beak and our fingernails are made of. Octopuses use it to crush the crabs and mollusks that they feed on.

79. pen
The ink is concentrated melanin, the same pigment that our makes hair and skin dark. Most octopuses have the ability to squirt this inky pigment, but not all. The ink also contains a compound called tyrosinase that irritates the eyes and sense of smell of the predator.

83. eyes
Octopus and human eyes are similar even though they developed on different paths. Each has a cornea, an iris, an accommodating lens, a fluid-filled vitreous humor, a retina, and so forth.
Octopus eyes focus like a camera with the lens moving in or out while our eyes use muscles to squeeze the lens to focus. The octopus eye, like other invertebrate eyes, develops as an invagination, or in-pocketing, of the skin. Human eyes develop as extensions of the brain.

85. Octopus life expectancy
6 months for smaller ones and up to 5 years for larger ones like the Giant Pacific octopus. Breeding is what does them in as they stop eating after breeding and essentially starve to death.

86. What is the smallest octopus
What is the smallest octopus? The Octopus Wolfi is half an inch long and weighs 1 gram

87. Largest octopus
Enteroctopus dofleini, also known as the Giant Pacific Octopus or North Pacific Giant

88. camoflauge
Chromatophores can you find the coral octopus?

89. reproduction
Cephalopods are gonochoric. A female typically possesses a single oviduct. A male produces spermatophores that it transfers to the female's genital pore by means of a specialized arm or tentacle. In some species, the specialized arm tip may be pinched off and left in the female's mantle cavity: this is known as the hectocotylus arm. Mating in some cephalopods includes courtship rituals that may consist of color changes, body movements, or combinations of both. Cephalopods exhibit spiral cleavage and are protostomous, but they have no larval stage: their development is direct. Octopods typically tend their eggs until hatching. Most cephalopods are semelparous

90. Octopus video

91. Cephalopod dissection

92. Mollusk review video