Presentation on theme: "Paul Ko Andy Zhao Michael Chiu Period 5"— Presentation transcript:
1Paul Ko Andy Zhao Michael Chiu Period 5 MolluscaPaul KoAndy ZhaoMichael ChiuPeriod 5
24 Major Classes: Polyplacophora Bivalvia Gastropoda Cephalopoda
3Class Polyplacophora Chiton Marine Shell with Eight Plates Foot used for locomotionRadulaNo head
4Bivalvia Clams and oysters Sedentary or sessile filter-feeding Marine and Freshwater or TerrestrialHead reducedPaired GillsNo radula
5Gastropoda Marine, Freewater/terrestrial Usually has a shell Aquatic and terrestrial snails and slugsMarine, Freewater/terrestrialUsually has a shellFoot for locomotionRadula
6Cephalopoda Predatory cuttlefish, squids and octopi. Marine Head surrounded by tentaclesTentacles usually have suckersExternal, internal or absent ShellMouth with or without radula
7Body Cavitieso The body cavities in Mollusca are called mantle cavities (coelom), which are:Water-filled cavities that house the gills, anus, andexcretory pores.There are also blood cavities known as hemocoelwhich store blood in open-circulatory mollusca.
8Body Symmetry All mollusca have bilateral symmetry meaning… The organism can be cut in half with the two sides looking more or less exactly the same.Ex:
9Nervous SystemRelatively complex nervous system, varies from species to species.All Mollusca have tentacles that have sensors to detect chemicals, vibrations and touch.Mollusca have ganglia, a sort of brain-like organ.
10Circulatory SystemOther than cephalopods, all Mollusca have an open circulatory systemThese cavities are known as hemocoel, and in mollusks, it has replaced the coelem.Cephalopods need a closed-circulatory system because their activities require more energy.
11Digestive System Radula to scrape up food Digestive tract is complete and ciliatedIncludes mouth, anus and complex stomachFood is taken up by the digestive glands arising from the stomach, where it is passed into the blood
12Excretory SystemWaste is in solid form so it prevents the fouling of water over gillsExcretory functions are regulated by a pair of nephridia and tubular structuresCollect fluids from coleom and exchanges salts and substances with body tissues during excretion
13Locomotion/Musculature Foot comprised of 3 main body partsViceral mass: contains interal organsMantle: fold of tissue over visceral mass, includes shell (if presentMantle Cavity: houses gills and anus and excretory skillsHerbivores are commonly gliders, move on muscular contractionCarnivores, more advanced locomotionCephalopods – Jet PropulsionCuttlefish/Sea Hares – Undulating later finsBivalves – Foot for burrowing
14N/A Skeletal System BUT…………………………. They have shells made of calcium carbonate
15Sensory Structures/Features Some mollusks have large complex eyes (notably the cephalopods)Squids can locate and capture transparent prey with specialized polarization vision.
16Reproduction Sexual Reproduction ReproductionSexual ReproductionExternal Fertilization: Sperm cell is united with egg cell away from the parents.Trochophore = LarvaeInternal FertilizationExample: Land snails are hermaphrodites. They have a pouch for holding the sperm of the mate.
17Gas Exchange Generally takes place in the true gills (ctenidia) Absorbs the Oxygenfrom water and diffusesCarbon Dioxide into thewater.
18Unique FeaturesMantle: Encloses mantle cavity, which circulates oxygen and water.Radula: The mouth, with teeth bent inwards CtenidiaCalcium Carbonate Shells
19QUIZ QUESTIONS!!1. Which of the following phyla do not have symmetry? a. Mollusca b. Porifera c. Echinodermata 2. Which of the following classes of Mollusca need a closed circulatory system? a. Cephalopoda b. Bivalvia c. Gastropoda d. Polyplacophora
20Quiz Questions (Cont.) 3. Excretory functions are regulated by… a. Nephridia b. Tubular structuresc. Both d. Neither4. Land Snails reproduce…a. Through internal fertilizationb. Through external fertilizationc. Sexuallyd. Asexually5. Why don't they serve escargots at a McDonald's restaurants?
21Answers1. b2. a3. d4. a5. They only serve fast food