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NAME___________________________________PERIOD________DATE_____________________ Symbiotic Relationships R.A.F.T. Write about the topics from the desired point of view and to the correct audience. Be creative with the format. If there is a variation you want to use, please talk to me to see if it fits. Role Insect Oxpecker bird Acacia tree tree Fish Saguaro cactus flower Spider crab Big Mac Fungus Leaf litter ants Cleaning fish anemone Algae Whale intestines Fish Spider Stink bug host Egg in puddle ants caterpillar Audience Grazing cattle rhinoceros ants bromeliads Larval mussel Its seeds bee algae intestines algae fungus barracuda Clown fish Tree sloth Barnacle tapeworm Sea lamprey Wasp's egg Wasp leech Horsehair worm crickets Wasp larvae Format letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter letter Topic Cattle egrets lunch Home sweet home Moving in hitchhiking White-winged dove pollen camouflage bacteria lichens Underground nest Stressful relationships house-cleaning camouflage hitchhiking Groceries stalking raising young kidnapping vampires grasshoppers Freeloading Home invasion *Show off your knowledge about symbiotic relationships. Include terms that your characters encounter (parasite, host, commensalism, mutualism, parasitism). Through your dialog describe what events are happening. NAME___________________________________PERIOD________DATE_____________________ Commensalism The Cattle Egret is often seen in the company of grazing animals. The grazers stir up insects, which the egret then eats. This is probably a loose sort of commensalism; there is no apparent benefit to the cattle. The commensalism is loose because the egrets will follow any cattle; in Florida, in fact, I have seen them following mowers. One example of a mutualistic relationship is that of the oxpecker (a kind of bird) and the rhinoceros or zebra. Oxpeckers land on rhinos or zebras and eat ticks and other parasites that live on their skin. The oxpeckers get food and the beasts get pest control. Also, when there is danger, the oxpeckers fly upward and scream a warning, which helps the symbiont (a name for the other partner in a relationship). The Acacia Tree is partially protected by large thorns, but it gets extra protection from Acacia Ants. The plant does 3 things to lure in the ants. First, the large thorns are hollow and provide a place for the ants to live. Second, the plants have swollen glands, nectaries, which produce a sugary solution the ants drink. The nectaries are obvious in the photo below. The third thing the plant does is to produce Beltian bodies, small structures which the ants bite off and eat; the Beltian bodies are rich in protein and supplement the sugars provided by the nectaries. In return for the room and board the ants chase off herbivores, kill and eat herbivorous insects, and destroy and plants that try to compete with the acacia. Bromeliads, a plant that lives in trees, avoid the hassle of crating a trunk to lift their leaves above the forest floor and closer to the sun. They simply grow on the branches of trees. Since the bromeliads don't take any nutrients from the trees this is usually classified as a commensalism. A larval mussel extends part of its body out of its shell to attract fish. The little mussels go into the mouth and pass over the gills. Here, they clamp down by closing the shell and digging in with the little teeth on the edge of the shell. They ingest blood from the fish as it swims upstream; some time later they drop off from the fish and begin their long (60 + year) life of filter feeding. The fish provides a meal and transport upstream (moving is not something mussels do well over long distances, particularly upstream). Mutualism: The white-winged dove has a mutualistic relationship with the Saguaro Cactus. The cactus provides food for the bird in the form of a large fruit. The bird consumes the fruit, also ingesting the cactus' seeds. The bird then flies off, and later deposits the seeds in a new location (with a nice dose of fertilizer to boot!). In this way, the cactus gets its seeds transported away from the parent plant, allowing it to potentially colonize new places. This type of mutualism is known as a dispersive mutualism. The bee and the flower. Bees fly from flower to flower gathering nectar, which they make into food, benefiting the bees. When they land in a flower, the bees get some pollen on their hairy bodies, and when they land in the next flower, some of the pollen from the first one rubs off, pollinating* the plant. This benefits the plants. In this symbiotic relationship, the bees get to eat, and the flowering plants get NAME___________________________________PERIOD________DATE_____________________ to reproduce. *Pollination is when the pollen from one flower gets into another flower, allowing the plants to reproduce. The spider crab and the algae. Spider crabs live in shallow areas of the ocean floor, and greenish-brown algae lives on the crabs' backs, making the crabs blend in with their environment, and unnoticeable to predators. The algae gets a good place to live, and the crab gets camouflage. The bacteria and the human. A certain kind of bacteria lives in the intestines of humans and many other animals. The human can not digest all of the food that it eats. The bacteria eat the food that the human can not digest and partially digest it, allowing the human to finish the job. The bacteria benefit by getting food, and the human benefits by being able to digest the food it eats. Lichens are mutualistic associations between a fungus and an algae or cyanobacteria. They are the terrestrial equivalents in some ways of corals. The fungus provides a tough, waterproof body able to withstand extreme environments on rocks and tree trunks. It is good at obtaining water and secretes acids to dissolve minerals from the rocks. It also produces carbon dioxide. All of these materials are then funneled to the endosymbiotic algae or cyanobacteria, which use the materials in photosynthesis and produce sugars which are then shared with the fungus. Some studies have shown that the fungus benefits from this relationship more so than the algae; at least under good conditions algae grown without the fungus grow faster then they do with the fungus. A leafcutter ant tending fungus in its underground nest. The fungus is almost completely dependent on the ants. The ants bring in nutrients (bits of plant leaves), prune the fungus back, transfer it to new bits of leaves (and even to new ant nests), remove competing fungi, bring in only leaf bits from trees without chemicals which would hurt the fungus, etc. Perhaps most amazing is the fact that the ants enlist a second symbiont - bacteria of the genus Streptomyces that the ants grow in specially modified areas of their own exoskeletons. The Streptomyces is then used to produce antibiotics that inhibit the growth of fungi which would compete with the fungi the ants are growing. A barracuda takes an unusual heads-up posture. He has arrived at the large brain coral, which makes a conspicuous landmark (seamark?) for tiny Cleaning Fish to set up shop. When the barracuda takes this pose, the Cleaning Fish know it is safe for them to approach - the baracuda is looking for a cleaning, not a meal. The tiny fish will scour the skin, mouth and gills of the Barracuda, removing any ectoparasites they find (and getting a good meal out of it). Finally, everyone who has seen "Finding Nemo" knows about the association between Clownfish and Anemones. By working its way carefully into the anemone, the clownfish gradually accustoms the anemone to the chemical makeup of the fish's skin; this gradual acclimatization prevents the anemone from stinging the clownfish (while fish with a different "taste" will be stung and eaten). The fish gets a safe house and some tidbits; the anemone gets cleaned and has the clownfish working as lures to bring in potential prey, or chasing away fish that would harm the anemone. Some scientists do not see any benefit for the anemone and classify this as a commensalism. The Tree Sloth has algae growing in its fur in Costa Rica. These algae help to camouflage the sloth NAME___________________________________PERIOD________DATE_____________________ against the lichen-covered tree (note the brown fur of the baby, not yet covered with algae). There is even a moth that lives only in the sloth's fur and consumes the algae; this is a commensal relationship between the moth and the sloth. Parasitism: A few examples of parasites are tapeworms, fleas, and barnacles. Tapeworms are segmented flatworms that attach themselves to the insides of the intestines of animals such as cows, pigs, and humans. They get food by eating the host's partly digested food, depriving the host of nutrients. Fleas harm their hosts, such as dogs, by biting their skin, sucking their blood, and causing them to itch. The fleas, in turn, get food and a warm home. Barnacles, which live on the bodies of whales, do not seriously harm their hosts, but they do itch and are annoying. The Sea Lamprey is a sort of temporary parasite. It latches onto a fish and uses the teeth to hold on and rasp away the skin, leaving an open wound for the lamprey to feed on. It drops off, usually without killing the "host". Sea Lampreys are not specific on any species of fish; they will latch onto any living thing and try to feed. A wasp has stung and paralyzed a spider. It will take the spider to a nest and lay an egg on it. The larvae will consume the still-living spider; often from the inside. This is usually considered to be a parasitoid relationship. A wasp burying its prey on the sand of a volleyball court. This wasp has stung and paralyzed a stink bug and is dragging it to its underground lair. Here it will deposit an egg and the larvae that hatches from the egg will eventually consume the bug. Keeping the bug alive but paralyzed ensures it doesn't rot. Leeches are usually thought of as ectoparasites (although some are predators). They attach to a vertebrate host and take a blood meal before dropping off. Most aren't adapted to a single vertebrate host, but they are highly adapted to sucking blood; their saliva includes anesthetics to help keep the host from noticing the bite, as well as anticoagulants to keep the blood flowing. A really strange parasite. The horsehair worm starts life as an egg laid in a puddle. The puddle dries out and a grasshopper or similar insect comes along and eats the egg, which promptly hatches and burrows through the gut of the insect into its body cavity or hemolymph. Here, surrounded by the nutritious blood of the insect it grows until it reaches adulthood. At that point it starts producing chemicals which take over the brain of the insect and cause the insect to seek out water, which it jumps into. The worm then exits the hopper and lives in the puddle, mating and laying more eggs. The grasshopper, if it doesn't drown, may survive the ordeal. A social parasite. This cricket lives in an ant nest. It disguises itself with a chemical signature that fools the ants into thinking it is just another ant. It is free to roam the nest and it even gets the ants to feed it. The Catalpa Worm is being parasitized by tiny wasp larvae. The adult wasps sting the caterpillar, NAME___________________________________PERIOD________DATE_____________________ injecting their eggs. The eggs hatch and devour the caterpillar from the inside, being careful not to disrupt any vital functions. Eventually they emerge and spin cocoons of silk in which they transition from larvae to adult. Technically, these insects are parasitoids, since, unlike true parasites, they kill their hosts. This is a fairly tight relationship; the wasps could not survive without caterpillars in the same family (although the caterpillar would do just fine without the wasps). *The final product must be in a written format.
