LESSON TWO - The Needs of Living Things - OceanLink

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The chemistry of a “black smoker.” After seawater seeps into the crust (1), oxygen and potassium (2) and thencalcium, sulfate, and magnesium (3) are removed from the water. As the water begins to heat up (4), sodium,potassium, and calcium dissolve from the crust. Magma superheats the water, dissolving iron, zinc, copper, andsulfur (5). The water then rises back to the surface (6), where it mixes with the cold seawater, forming blackmetal-sulfide compounds (7).Image courtesy of Woods Hole Oceanographic Institution.Text from Ocean Explorer:oceanexplorer.noaa.gov/explorations/02fire/background/education/media/ring_candy_chemo_9_12.pdf3. Exploring SymbiosisIf you have poked around in a tide pool, you have probably seen bright green sea anemones that lookmore like flowers than animals. The anemone is green because it has an algal partner (or symbiont)that is green! These giant green anemones, Anthopleura xanthogrammica, are an example ofsymbiosis. The anemone provides a secure home for the algae, and the algae make sugars byphotosynthesis for the anemone.There are three different ways in which organisms can engage in a symbiotic relationship. Mutualism isa close relationship between two organisms in which both organisms benefit. Parasitism is arelationship between two organisms in which one is harmed and the other benefits, and commensalismis a relationship in which two organisms live together where one benefits while the other is unaffected.In the deep-sea there are many relationships among organisms that may seem strange and unusual toyou. At hot vents and cold seeps, unique food chains were discovered completely reliant onchemosynthesis. When worms found at hot vents like the Giant Tubeworm, Riftia, were looked at,biologists found that this worm was “gutless”. It took a while, but what they discovered was a uniquechamber inside the animal, called a trophosome. The trophosome contains microbes that need sulfidecompounds to produce sugars. These sugars are then consumed by the tubeworm. The GiantTubeworm and the microbes are so interconnected that they cannot survive without each other. Whenhydrothermal venting stops and the tubeworm can no longer provide chemicals to the bacteria, bothorganisms die.Similar symbiotic relationships between tubeworms and microbes, and between clams and microbesexist at cold seeps like the one found in Barkley Canyon.. Deep-sea clams farm methane-munchingmicrobes in their guts providing the microbes with methane. The clams then harvest the sugars madeby the microbes, showing another example of producers and consumers living together to meet theirsurvival needs. Other clams, such as “V” clams (“Vesicomyid Clams”) commonly seen in vent fieldsand at cold seeps, live by sucking sulfide through their foot from the mud. Sulfide travels through the
Lesson Two – The Needs of Living Things 5 Science on the Leading Edge (S.O.L.E.)-V-clam’s body to the gills where gizzillions of microbes live. The gills absorb oxygen, carbon dioxideand water giving the bacteria all of the chemical elements they need to produce sugars. For moreinformation on Cold Seeps and V-clams, check out College of Marine Science: Project Oceanographyhttp://www.marine.usf.edu/pjocean/packets/sp02/sp02u2p4.pdf- (Cold Seeps and V-Clams.doc)These are just three examples of symbiosis. In the sea and on land, there are thousands of animals thathave symbiotic relationships.4. The Needs of Living ThingsAll organisms must have their basic needs met in order to survive. Organisms live successfully inecosystems that supply them with their basic needs, such as food, water, and suitable living conditions.In general, the survival needs of organisms include an energy source, oxygen, water, and shelter.The physical space where an organism lives is called its habitat. We have researched the habitats ofthree of the NEPTUNE Canada Nodes sites in Lesson One (Folger Passage, Barkley Canyon, andEndeavour Rideg). For this lesson, we will examine some of the organisms that live in each of theecosystems, and assess how their survival needs are met.Materials:• Computers with internet access• Download and print copies of Photosynthesis vs Chemosynthesis Worksheet• Download and print copies of Symbiotic Relationships Activity (Reference: Adapted fromOhio Department of Education http://www.edquest.ca/pdf/7final03key.pdf)• Download and print copy of Organism Lists (for teacher).• Download and print copies of Critter Card Template.• Markers or crayons for drawing on Critter CardsProcedure:1. Begin by reviewing the key concepts found in this lesson (organism, species, population,community, ecosystem), giving examples for each. Having the vocabulary list on the board or asan individual handout for reference during the lesson will be very helpful.2. Lead a discussion about the essential needs for life. Get them to think about all living things, fromthe smallest microbe to their own needs for survival.3. Using the board, brainstorm with the class to create a concept map outlining their survival needs.What provides each of the needs? Are their needs inter-connected?4. Focus on energy source. Introduce photosynthesis, and the importance of organisms that can maketheir own food. Ask the class if they can think of any ecosystems that thrive without sunlight asthe energy source.5. Introduce chemosynthesis, and the idea that ecosystems can exist without sunlight. In theseecosystems, the organisms that provide the rest of the food web with energy use chemicals as theenergy source to make sugars rather than sunlight. Ensure that the students understand this processon a basic level.6. Use the Dive and Discover Website http://www.divediscover.whoi.edu/vents/light.html to compareand contrast Photosynthesis versus Chemosynthesis. This interactive animation is a great tool to
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LESSON TWO - The Needs of Living Things - OceanLink

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