1. Mollusk / Annelids
Mollusk

2. History of Worms

3. Section Objectives: Identify the characteristics of mollusks.
Compare the adaptations of gastropod, bivalve, and cephalopod mollusks in their biomes.

4. Phylum Mollusca Snails, clams, squids, slugs and oyster are examples.
Found freshwater, ocean or moist terrain.

5. Bilateral symmetry -
Distinct regions mirrored on a left and right axis.

6. 9 Structures

7. 1. Radula
Tongue like organ that protrudes from the mouth used for eating algae. Contains rows of tiny teeth that are used for scraping algae from surfaces.
A radula may have as many as 250,000 teeth.

8. Radula
Radula

9. 2. Mantle
soft, moist layer inside the shell of mollusks.
Mantle

10. 3. Shell
outer layer.
Most made of calcium carbonate. CaCO3
Shell

11. 4. Gills gas exchange occurs through the mantle and the gills.
Gills also filter food particles from the water.

12. 5. Foot
extends out and helps with movement.
Foot

13. 6. Heart Has a 3 chambered heart.
a. Open circulatory system - blood moves through vessels and into spaces around the body organs.
Ex: Snails, squid, and clam

14. 6. Heart
b. Closed circulatory system - blood moves through the body enclosed entirely in a series of blood vessels.
Some mollusks, such as octopuses, move nutrients
and oxygen through a closed circulatory system.

15. Mollusks have a well-developed circulatory system that includes a three-chambered heart.

16. 7. Siphons
act as devices to let water in and out of mollusks.

17. 8. Nephridia
tube like structure that form the excretory system.

18. 9. Visceral mass area located between the muscular foot and mantle
contains most of the internal organs.

19. Mollusk Diversity
Form the second largest phylum. Contains 7 different types of mollusks.
First animals to have evolved respiratory organs.

20. Classified according
to shell type, muscular foot structure, and arrangement of internal body organs.

21. Chitons
live on rocky surfaces in shallow water. Ex: Chitons ( KY - tunz)
Most primitive mollusks, do not have a ganglia and have simple sense organs.

22. Chitons
Have 8 overlapping plates.

23. Snails and Slugs largest class of mollusks.
Have a radula that scrapes up algae or tears apart plants or one piece shells.
Have sense organs concentrated in the head region. Open circulatory system.
Aquatic gastropods use gills as respiratory organs.

24. Snails and slugs
Sea slug
Ex: snails or slugs
snails

25. Bivalves
Do not have a head, have two shells attached by a hinge, have sense receptors, ganglia, most are marine, and do not have a radula.
Filter feeders.

26. Bivalves
Ex: clams, mussels, scallops and oysters
mussel
scallop
clam

27. Cephalopods Tentacled mollusk modified head and foot regions.
Have a highly developed nervous system, sense organs, usually no external shell, closed circulatory system and can usually swim fast.

28. Octopus

29. Cephalopods
Ex: squids, nautiluses, octopuses, Cuttlefishes. Most recently evolved mollusks.
squids
Cuttlefishes
octopuses
nautiluses

30. Cuttlefish

31. Nudibranch

32. Mollusks
Octopus
oysters

33. Mollusks

34. Trivia:
The largest-known squid was 57 feet (17.5 m) long.

35. 1. In shelled mollusks, the ___________ secretes the shell.
2. Bivalves obtain food by ______________.
3. ______________ have two shells.
4. The excretory structures that remove metabolic wastes from the bodies of animals such as mollusks and annelids are called ________________.
Mantle
Filter Feeding
Bivalve
Nephridia

36. 5. An animal whose blood moves throughout its body within blood vessels has a(n) ___________________.
6. The ____________ is a tongue like organ with rows of teeth that is used by gastropods to scrape, grate, or cut food.
7. The most complex and most recently evolved mollusks are _______________.
Closed Circulatory system
Radula
Cephalopods

37. 8. What compound are most shells composed of?
9. ____________ are involved in removing wastes from a mollusk’s body.
10. Which animal is believed to be smarter a snail or a squid?
CaCO3 and SiO2
Siphons or Nephridia
Squid

38. Annelids

39. Annelids earthworms, leeches and many segmented marine worms.
Classified by the presence or absence of setae or parapodia.
brown
Brown sea worm
leech

40. Ex: earthworms

41. Earthworm movement

42. 11 Structures or Systems of earthworm

43. 1. Setae
Bristles that help classify annelids depends on the number and presence of the bristles.
Help to anchor each segment in the soil and help with movement.

44. 2. Parapodia
leglike structure

45. 3. Nephridia
excretes the wastes.

46. 4. Crop
temporary storage organ. 4

47. 5. Gizzard
Grinds up soil , freeing the organic matter and breaking it down. 5

48. 6. Intestine long , straight tube where organic matter digested.
Eat their way through the soil. (Casting - earthworm’s waste) 6.

49. 7. Circulatory system closed system.
(Aortic arches - muscular structures that functions as simple hearts by contracting and forcing blood into the ventral blood vessels. 7

50. 8. Respiratory system
Gas exchange takes place across the skin. Skin must be moist for diffusion of oxygen to take place.
Produce a mucous secretion and have an outer cuticle that helps keep skin moist.

51. 9. Nervous System has a small brain made up of fused ganglia
At the anterior end of the digestive tract.

52. 10. Reproductive system
Reproduce sexually, are hermaphrodites, but cannot fertilize their own eggs.
When mate join head to tail and secrete a mucus covering around the joined areas and each worm then releases sperm into a special sac in the other worm.

53. 11. Skeletal system
hydrostatic (fluid filled to hold shape).

54. Earthworm Anatomy

55. TRIVIA:
Earthworm eggs hatch in 2-3 weeks.

56. Bristleworms
Fan Worms
bristleworm

57. Bristleworms largest and oldest class of phylum Annelids.
Gas exchange takes place across the surfaces of the parapodia.
Are typically free swimming or tube dwelling marine annelids.

58. leeches usually freshwater parasitic annelids.
Attach to host with a pair of suckers or hooks.

59. Uses of Mollusks and Annelids
Mollusks (clams, oysters , etc are important food sources.)
Annelids - by burrowing through the soil, help to loosen , allowing water and air to pass easier.

60. Doctoring with Leeches

61. The medicinal leech is best known as the organism used for blood letting (people used to believe many health problems caused by getting rid of "bad" blood). Surprisingly, they are being used once again to remove blood from hematomas (areas of blood leakage) resulting from surgery (like re-attaching severed limbs, etc.). The ability of the leeches to parasitize humans and other mammals depends on a variety of adaptations that allow them to pierce or cut into skin without notice.  Hirudo uses three sharp cutting plates (teeth) like circular-saw blades to make a Y-shaped incision in the skin.  While cutting the skin, it secretes an anesthetic as well as a histamine-like substance that keeps the blood vessels open. The blood is then sucked into the pharynx. While it is being swallowed, an anticoagulant protein called hirudin produced by the salivary glands is added to the blood to prevent it from clotting. After the salt-water from this blood is eliminated by the nephridia, the concentrated blood is stored in within numerous diverticula (outpocketings) of the crop called gastric caeca (ceca). The proteins of hemoglobin and other components of the blood are then digested extremely slowly (as long as 200 days), which provides enough energy to live another 100 days without feeding!  Surprisingly, the gut does not secrete digestive enzymes.  Instead, the leeches rely on bacteria in the gut for enzymatic digestion.  In the medicinal leech, a single species of bacterium digests the blood and also produces an antibiotic that eliminates any other bacteria from the digestive tract, allowing the red blood cells to remain unspoiled within the leech for up to a year! This also means that you don't have to worry about getting a bacterial infection from the leech!
Medical Leech

62. Leeches therapy

63. Trochophore
ciliated, pear shaped larval form of mollusks and annelids.