Title: Lesson 11: Molluscs – Part 1



Title: Lesson 11: Molluscs – Part 1Date: Grade Level: Biology 11IRP and PLOs (G1 and G4 both on p 18) Science - Biology, Grade 11, G4 and G1, p. 42: G4. analyse the increasing complexity of the Phylum Mollusca, the Phylum Echinodermata, and the Phylum Arthropoda (main PLO)And G1 analyse how the increasing complexity of animal phyla represents an evolutionary continuumGeneral purpose/Goals/Aim: to allow students to explore the Phylum Mollusca and relate the characteristics of organisms in this phylum to the “big picture” of the phylogenetic tree and evolutionary historySpecific Objectives (SWBAT) (number each objective)examine members of the Phylum Mollusca and describe their unifying characteristicsdescribe how molluscs carry out their life functionsdescribe how molluscs have evolved to adapt to different nichesdescribe molluscs' ecological role in the environmentBackground knowledge/information required- what an animal is defined as and its characteristics- knowledge of Porifera, Platyhelmenthes, Nematoda, and AnnelidaSetup/Safety (if any)- have powerpoints loaded and any internet videos ready to switch to and loaded – this will prevent issues due to poor internet connectionPre-assesment, probing of previous knowledge- pre-assessment/probing will occur in the first few minutes of class and involve a discussion of the previous phyla and a review of its characteristics: this will help in relating the concepts learned about molluscs to the “bigger picture” of biology- pre-assessment will also include probing of knowledge about molluscs – have students heard of these animals before? Can they name any examples?OBJ.TimeTeacher ActivityStudent ActivityMaterials/AidsG3~ 4 min ~ 10 min- Introduction (hook): teacher shows video that teaches students can learn how to create their own worm bin at home to compost – annelids’ place in the world)- students participate in teacher-facilitated review of annelids: students each get a piece of paper and draw an annelid, marking main features- teacher has students participate in classroom discussion: teacher lists main features - students watch video- students participate in discussion of annelids, referencing their notes- powerpoint notes (appendix 11C)- overhead projector or board and chalk/pen1, 3, 415min- Notes (Molluscs Intro): teacher goes over that notes describe main features of molluscs and goes over examples of them, showing what the main features look like in different forms and animals and going over ecological roles of molluscs- students copy notes- powerpoint notes (appendix 11C) 1, 3~ 3 min~ 20 min~ 7 min- Activity: Mollusc Inquiry: teacher uses powerpoint to display slide of many pictures including slug, nudibranch, land snail, abalone, sea snail, scallop, clam, mussel, oyster, octopus, squid, nautilus, cuttlefish- teacher hands out worksheet and goes over instructions with students, asking them to cut out the images and complete the activity- students pair, share, and participate in teacher-facilitated classroom discussion of the activity (see appendix 11B for answers and guiding questions)- students examine the animals and ask any questions if they need clarification on what they are looking at- students complete activity and ask questions - powerpoint notes (appendix 11C)- Activity Handouts (appendix 11B)- scissors- glue sticksOBJ.TimeTeacher ActivityStudent ActivityMaterials/Aids1, 310 min- Notes (Molluscs Classes): teacher goes over notes describing mollusc classes, using student-generated observations listed on the board to describe the three classes of molluscs (gastropods, cephalopods, bivalves)- students copy notes and participate in discussion when class is asked questions- powerpoint notes (Appendix 11C)1, 3, 45 min- Closure: teacher instructs students to write a response to the questions on the powerpoint:“Was your way of classifying molluscs into three groups similar or different to the way that scientists do it? In what ways are they similar or different?"- students complete venn diagram (as part of their notes) between annelids and molluscs and pair and share- powerpoint notes (Appendix 11C)Summative Evaluation- none this class: main evaluation will be will be formative – summative occurs next day with the issuing of a quiz- formative evaluation: student understanding can be gauged and thinking can be monitored by listening to student discussion during class and asking students to explain their decisions- questions for use on exam:Which of the following animals is NOT a mollusc?squid snailjelly fishoysterWhat is the main purpose of a radula?breathingfeedingmovementreproductionWhich of the following is NOT a class of the Phylum Mollusca?GastropodaBivalviaCephalopodaChordataName two common features that ALL MOLLUSCS have. (2 marks) A mantle, soft body, muscular foot, or visceral mass. What is the mantle, and what does it do for a mollusc? (2 marks)The mantle is an outer coating that encases the visceral mass – it encases the inner organs of the body and secretes the shell. Many molluscs have shells. Describe what the shell is made of and explain why it can be an evolutionary advantage to have one. (2 marks)The shell is made out of calcium carbonate (CaCO3) and is secreted by the mantle. It is an advantage to have a shell because molluscs have very soft bodies. This shell provides them structure and protection from predators.References and Background reading:Ch 27 in text: Miller, K. and Levine, J. (1995) Biology, 3rd Edition. New Jersey: Prentice Hall Inc.Extension activities:-students who finish early can work on this crossword: can assign prereading for Phylum Echinodermata (Chapter 28)Notes to self? Amir Atabeygi 2005APPENDIX 11A: INFO TABLE ON MOLLUSCS: Key points soft body muscular foot radula mantle (produces shell if present, contains internal organs) Examples clam, mussel, oyster, limpet, chiton, nudibranch (sea slug), snail, squid, octopus Mobility gastropods (snails and limpets) and chitons use their muscular foot along a substrate, clams use it to dig in the sand, swimming scallops contract their muscles repeatedly to open and close their shell and mimic a swimming motion, cephalopods (octopus and squid) move by water propulsion (projecting water from their siphon), additionally squid use their fins and octopus use their suction-cupped arms Respiration gills, nudibranchs have exterior gills projecting flower-like from their posterior end, bivalves take in and eject water from their siphons Response / Protection abalones twist violently, snails can close the “trap-door” (called an operculum) to their shell, bivalves can close up tightly, cephalopods can change colour Feeding most gastropods are herbivore grazers, scraping algae off the substrate using the radula, bivalves are filter feeders using their siphon, cephalopods are excellent hunters with strong beaks to eat their prey Reproduction lots of variation, most cephalopods are terminal spawners, bivalves are broadcast spawners, nudibranch are hermaphroditic, gastropods are external fertilizers Conservation Issues bivalves are indiscriminate eaters and so are susceptible to pollution, abalones are endangered Cool Facts The Gumboot chiton is the largest species at up to 35 cm long (and lives in BC) The Giant Pacific octopus, also the largest and found in BC, can reach a maximum arm span of 7.3 m (24 feet) and weigh up to 72.7 kg (160 lbs.) The largest invertebrate is the Colossus squid, at 19 m and weighing in at 450 kg The octopus is the smartest invertebrate. T here is also the classic experiment involving two freshly caught, and therefore na?ve, octopus. The two are placed in side-by-side glass aquariums, enabling them to see each other. The first octopus is presented with a screw-top jar containing food, such as a crab. It takes the octopus a given amount of time to determine how to open the jar and retrieve the food. The second octopus, when presented with the same problem will accomplish the task in a fraction of the time demonstrating that it has watched and learned from the experience of the first octopus. Check out YouTube for some amazing videos of octopus changing colour and fitting through tiny spaces (the largest hard part on their body is their beak) The eyes of scallops are extremely overdeveloped given the lack of a brain to analyze images. Scallop eyes have a cornea, lens and retina. *Table made by the Vancouver Aquarium and borrowed for aiding a TOC who may not have a background in the material or using as a cheat sheet during class.APPENDIX 11B: MOLLUSC GROUPING ACTIVITY:Teacher’s Notes:The purpose of this activity is to take an inquiry-based approach to teaching students the differences and similarities between cephalopods, gastropods, and bivalves (the three classes of Molluscs mentioned in the Miller & Levine textbook). Students will have been assigned reading of Chapter 27 the class prior, but the due date is not until next class and the last third of the chapter deals with these three classes. By utilizing an inquiry-based approach, students can explore using their own classification systems to determine common features and be guided to determine the characteristics of the three classes on their own.Students will be provided with one handout and one sheet of animal images each. Ensure scissors are provided so that students can cut out their animals (12 in all). While this activity is ongoing, also display the powerpoint slide with the images of animals featured on their sheets so they can see better quality images of what the animals look like alongside their cartoon drawings. Introduce the activity to students by handing out the worksheet and displaying the powerpoint and explaining that while all Molluscs have common features (ask them to recall – it was on a previous slide) they take different forms and some molluscs have features that others don’t. Explain the purpose of the activity is to encourage students to learn how to classify these animals based on common characteristics and go through the instructions with them. While the activity is ongoing: circulate, answer questions, and challenge students to come up with different criteria for grouping their animals. After the activity: encourage students to share their groupings and what animals they grouped with others. Encourage discussions about what common features these animals have and how they relate to the general features a mollusc has. Guiding questions:What features did you choose to group these animals by? Why?Within the groupings you have outlined, where do you think the foot is?Within the groupings you have outlined, where do you think the visceral mass is?Within the groupings you have outlined, where do you think the mantle is?Within the groupings you have outlined, where do you think the foot is?How do these animals protect their soft bodies?What are evolutionary advantages to having a shell? Disadvantages?What about those molluscs without a shell – how do they compensate for the lack of it?Please find the worksheet and images of animals to be handed to students attached.NAME:_______________________ BLOCK:____________DATE:_____________________Matching MolluscsINTRODUCTION:Molluscs come in many shapes and sizes and have very different features. Even though they all look different, though, some things are the same for all of them. There are also some features that are shared between members of sub-groups of molluscs. The purpose of this activity is to give you a chance to explore some of these differences yourself, and to find out how molluscs are similar and different.INSTRUCTIONS:Cut out all 12 of the images of molluscs from the attached piece of paper. Come up with as many different ways to group them as you can (but at LEAST 6). For example, you can group molluscs according to whether or not they have shells, or by number of tentacles, or by size. Every time you come up with a grouping, write it down on this worksheet under the heading “My Pairings – it continues on the back of this sheet. Be prepared to share your results with the class!When you are given a time warning of five minutes left, move onto the last section. Glue down your animal images in the way that you think is best and write a few lines about why you grouped them this way. MY PAIRINGS:I grouped my molluscs by…The molluscs in my groups were…THE LAST SECTION:The animals you have been examining are grouped into three sub-phyla or Classes. Decide the best way to divide your molluscs into three general groups and glue down the images into the three spaces provided. Beside the spaces, briefly explain why you grouped these molluscs together – what common features did you notice?I grouped my molluscs by…The molluscs in my groups were… ................
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