1. Chapter 35

2. Section 35.1 Video

3.  Means “soft body”  Most marine, some freshwater, a few terrestrial

4. TerrestrialFresh Water Marine

5.  Definition: a body cavity that is completely lined by mesoderm and contains internal organs  Found in the following phlya:  Mollusca (clams)  Arthropoda (crayfish)  Echinodermata (starfish)  Chordata (humans)  Annelida (earthworms)

6.  Trochophore: larval stage of development for aquatic mollusks and annelids  Use cilia for swimming and feeding  Some have a hard shell for protection

7.  Body divided into 2 main section: head- foot & visceral mass:  Head-foot: head (mouth, sensory structures) and foot (locomotion)  Visceral mass: heart & digestive, excretion, and reproductive organs  Covered by the mantle

9.  Mantle: layer of epidermis that excretes a hard shell of calcium carbonate  Mantle cavity: space between mantle and visceral mass that protects the gills  Ganglia: clustered nerve cells that control locomotion & feeding  Radula: flexible, tongue-like strip of tissue covered with abrasive teeth

10. Video

11. radula – rasping “tongue” of chitin

12. 1. Class Gastropoda 2. Class Cephalopoda 3. Class Bivalvia

13. (Snails, nudibranchs, cowries, whelks)

14.  Largest and most diverse group of mollusks  Examples: snails, abalones, conchs, slugs  Locomotion: wavelike muscular contractions on mucus slime trail  Can withdraw head into mantle cavity when threatened Video

15.  Hemolymph: circulatory fluid  Hemocoel: fluid filled spaces  A.k.a. blood cavity

16.  tentacles- sense touch & have eyes on ends  respire with gills (aquatic) or exposed blood vessels (terrestrial) by diffusion  we eat muscular foot “escargot”

23. shoot, then inseminate (mucus paralyzes female reproductive tract) successful darters double success

24.  Examples: octopuses, squids, cuttlefishes, chambered nautiluses  Marine animals, free swimming  Meaning “head-foot”

25.  Tentacles have large suction cups  Largest invertebrate brain  Highly advanced eyes similar to humans  Closed circulatory system  Many release dark, inky fluid when alarmed  Many have pigment cells called chromatophores for camouflage Video

26. Squid, chambered nautilus, cuttlefish, octopus

27.  Examples: clams, oysters, mussels, scallops  All have a two part shell connected by hinge closed by adductor muscles  aged by shell rings  sedintary  filter feeders Video

28.  2 siphons at the posterior end:  Incurrent siphon = intake of water & food  Excurrent siphon = output of water & wastes  Clams dig in the soil so only their siphons stick out  Filters about 3 quarts an hour! Video

30.  Calcium carbonate secretion around a foreign object  Protection of the soft visceral mass  Made by the mantle (just like the shell)

31.  ----------- protective outer layer   ///////////// prismatic layer  ----------- pearly layer

33. He Was Shellfish

34. Body parts you MUST identify & show me during the lab:  Umbo  Valves (shells)  Mantle  Gills  Incurrent & excurrent siphons  Palps & mouth  Digestive gland  Intestine  Gonads  Heart

35.  clam Oldest part

36. ANTERIOR POSTERIOR VENTRAL DORSAL

39. Section 35.2

40.  Examples: earthworms, leeches  Annelid means “Little rings”  Segmentation allows for division of labor  Bilateral symmetry  Live in freshwater, marine water, and terrestrial environments

42.  Setae: external bristles  Parapodia: fleshy protrusions on outside of body  Number of setae and parapodia divides this phylum into three class: 1. Class Polychaeta 2. Class Hirudinea 3. Class Oligochaeta

43.  “Many bristles”  Number of setae and parapodia  Have anetennae & specialized mouth parts  Most are marine animals  Trochophore larvae  Predatory  Largest class of annelids Video

45.  Smallest class of annelids  Example: leeches  Live in calm freshwater & moist vegetation  No setae or parapodia  Most are carnivores & some are parasitic  Secrete anaestheic & anticlotting factors  Ingest 10 times it own weight in blood!

46.  “Few bristles”  Few setae and no parapodia  Live in soil or freshwater  Example: earthworms

48.  Divided into over 100 segments  Movement:  Anchor middle segments with setae  Contract muscles in front  Elongation of anterior  Setae of anterior grip ground  Pull posterior forward

50.  Ingest soil as they burrow  Digestion path: mouth  esophagus  crop (temp. storage)  gizzard (releases & breaks up organic matter)  long intestine (absorption of nutrients)  anus

51.  Closed circulatory system  Ventral (toward posterior) & dorsal (toward anterior) vessels  Aortic arches link ventral and dorsal vessels

52.  Respiration: diffusion of oxygen and carbon dioxide via moist skin  Secretion of mucus to keep moist  Excretion: via nephridia (excretory tubules in every segment except first three)

53.  Chain of ganglia connected by a ventral nerve cord  Each segment has a single ganglia  Brain = fused ganglia  Simple sensory skills  Light  Touch  Chemicals  temperature

54.  Hermaphrodites  Cannot fertilize own self  Mating: press ventral surfaces together, anterior ends pointed opposite directions  Setae hold worms together  Mucus secretion from clitellum  Each worm injects sperm into mucus  Sperm going into seminal receptacles of other worm  Several days later chitin tube forms picking up eggs & stored sperm  fertilization  Young worms develop inside tube and hatch 2-3 weeks later

55.  Decomposers of leaves and organic matter  Recycle nutrients  Release natural fertilizers (waste)  Aerates the soil