Wake Tech BIO 112 - Community Ecology Assignment

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Assignment: Community EcologyPart 1: Two-Species InteractionsPart 2: SymbiosisPart 3: Facultative vs. Obligatory InteractionsPart 4: Coevolution in NewtsPart 5: Food Web AnalysisAssignment: Community EcologyPart 1: Two-Species Interactions One way to categorize interactions between two different species is to define the interaction by the outcomes: - A mutualism is an interaction that benefits both species. Almost always, mutualisms involve the exchange of two different types of resources: Food forprotection, for example.- Competition is an interaction between two species both attempting to use thesame resource, when the resource is in limited supply. Thus, both species arehurt by the interaction.- Predation / Parasitism / Herbivory: We have three terms for interactions in which one species benefits and one species is hurt.o Predators kill and eat the prey species.o Parasites eat or live on their hosts, but do not always kill the host.o Herbivores are animals that eat plant tissues.o But notice that in each case one species benefits from the presence of the other species, while the other species is hurt.- Commensalism is an interaction in which one species benefits and the other species is not particularly affected. It can be hard to define a commensalism, because interactions tend to affect the species involved, and any effect will shift a commensalism into a mutualism or a predation-type interaction. Read the interaction scenarios below and decide whether the interaction is competition, commensalism, predation, parasitism, herbivory, or mutualism. Fill in the information on the table below. - Scenario A: On the edge of an alpine meadow, a beaver cuts down an aspentree. It eats the bark, uses some of the timber to shore up its dam, and storessome of the branches underwater for it to eat later in the winter.- Scenario B: You are camping in the meadow. A female mosquito smells you.She finds a piece of exposed skin, drills her proboscis through your skin to find a capillary, and sucks up your blood. - Scenario C: That evening you watch as an elk and a white-tailed deer, both grazing ungulates, eat the same kinds of plants in an alpine meadow. - Scenario D: The next day you notice some colorful flowers. A butterfly walksover a brightly blooming inflorescence. It finds nectar stored inside the flowers and eats the nectar. In the process it gets pollen smeared on its body.When it is finished hunting for nectar, it flies to another flower of the same species a little ways away to find more nectar. Some of the pollen gets scraped off onto the second flower.Adapted from a case study by Eric Ribbens Department of Biological Sciences Western Illinois University- Scenario E: A hawk soars over the meadow. Its sharp eyes spot a field mouse. The hawk drops into a steep dive and catches the mouse in its talons.Then it flies away, to feed the dead mouse to its nestlings. - Scenario F: On the edge of the meadow is a large tree. Growing on the tree’s bark is a circular gray-green lichen, about 6 inches in diameter. The lichen is using the tree for habitat. The trunk gets sun and the lichen isn’t competing with other organisms for space. The tree hardly notices the lichen;it isn’t eating the tree or taking resources from the tree. - Scenario G: In the wetter part of the meadow there is standing water. In the shallow water, a cattail (a tall grassy plant) and a rush (another kind of grassy plant) are both growing. The cattail and the rush both prefer the samekind of habitat, both need sunlight, and both are sucking up nitrogen and other nutrients from the marsh mud. Scenario Type of InteractionA HERBIVORY B PARASITISM C HERBIVORY/ COMPETITION D MUTUALISM E PREDATION F COMMENSALISMG COMPETITION Part 2: SymbiosisSymbiosis is another type of two-species interaction. It literally means living together, and refers to pairs of species that live in close physical proximity with the other species for a major part of their life cycles. Some examples of symbiosis include:- You and the microorganisms that live in your intestines; - bark beetles burrowing in pine tree trunks; - Monarch butterfly caterpillars and milkweed plants; andAdapted from a case study by Eric Ribbens Department of Biological Sciences Western Illinois University- Dinoflagellates living in coral tissues. Can you think of any symbiotic interactions that are commensal or parasitic? Fill in examples for each in the blank cells in the table below:Interaction ExamplesMutualism • Monarch butterfly caterpillars and milkweed plants• Dinoflagellates living in coral tissues.Commensalism • bark beetles burrowing in pine tree trunksParasitism • You and the microorganisms that live in your intestinesPart 3: Facultative vs. Obligatory Interactions Another idea, especially applied to mutualism, is whether the interaction is facultative or obligatory. A facultative interaction is one that is not essential for the survival of the species involved, while an obligatory interaction is essential for one or both of the species involved. Classify the following examples as mutualism, parasitism, or commensalism. Determine if each example is obligatory or facultative. Fill in the information in the tale below. - Example 1: The interaction between a fungus and an algae cell forms lichen.The fungi provide the algal cell with water and nutrients from the environment. The algae provide the fungi with carbohydrates produced during photosynthesis. These organisms cannot be cultures alone; when separated the organisms cannot grow or reproduce successfully. - Example 2: Cattle egrets are insectivores. The cattle egret will eat insects that have been disturbed when the cattle forage. @- Example 3: A spider building a web on a tree; this allows the spider to easilycapture prey. - Example 4: Aphids are tiny insects that use their pointed snout to suck fluidsfrom the phloem of plants. Adapted from a case study by Eric Ribbens Department of Biological Sciences Western Illinois University- Example 5: Yucca moths and yucca plants have a reciprocal obligate relationship- the plants cannot make seeds without the yucca moth, and the moth larvae only reach maturity if they eat developing yucca seeds.- Example 6: Fig wasps lay eggs on figs. The male fig wasp is wingless and does not leave the fig tree. Female fig wasps fly great distances to lay eggs and fertilize the fig trees that she visits. Figs can only be pollinated by fig wasps. Example Type of

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Wake Tech BIO 112 - Community Ecology Assignment

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