Community Ecology Homework

1.  Explain the differences between competition, predation, parasitism, mutualism, and commensalism and give an example of each.
Competition- (–/– interaction) occurs when species compete for a resource in short supply example when an invasive species moves in it cause competition. Large insects defend feeding sites on cottonwood leaves by kicking and shoving smaller aphids from better sites.

Predation- (+/– interaction) refers to an interaction in which one species, the predator, kills and eats the other, the prey for example such as carnivores or a lion eating a deer. Parasitism- (+/– interaction), one organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process example such as a leech getting nourishment from it host will harming the host Mutualism- (+/+ interaction), is an interspecific interaction that benefits both species example a bee pollinated a flower (bee can make honey, flower can reproduce) Commensalism- (+/0 interaction), one species benefits and the other is neither harmed nor helped example such as bird living in a tree. (birds can live, tree does nothing)

2.  Describe the differences between Batesian and Müllerian mimicry.

Batesian mimicry a palatable or harmless species mimics an unpalatable or harmful model Müllerian mimicry is when two or more unpalatable species resemble each other

3. Search for information on the relationship between Monarch and Viceroy butterflies. Is this a case of Batesian or Müllerian mimicry? Justify your reasoning. The viceroy has recently been discovered to be actually just as unpalatable as the monarch, making this a case of Müllerian mimicry; because when two or more unpalatable species resemble each other.

4.  Explain the Competitive Exclusion Principle and how it relates to the concept of the ecological niche. Animals that have the same niche will end up competing for the niche because the competitive exclusion principle states that two species competing for the same limiting resources cannot coexist in the same place. And the total of a species’ use of biotic and abiotic resources is called ecological niche and because of the principal no two species can have the same exact ecological niche.

5.  Discuss if the Competitive Exclusion Principle explains the spacing of fast food restaurants on the “strip” in most towns. The competitive exclusion principle states that two species competing for the same limiting resources cannot coexist in the same place. Fast food restaurants are competing for the same resources in this case would be their customers. The restaurants space them themselves on strip because they cannot coexist in the same place because they would be competing for customers (resources) causing the elimination process of them competing until one restaurant moves or dies off.

6. According to the principle of competitive exclusion, what outcome is expected when two species (or businesses) with identical niches compete for a resource? Why? The competitive exclusion principle states that two species competing for the same limiting resources cannot coexist in the same place. So when two species (or businesses) with identical niches compete for a resource one is going to be kicked out or eliminated from lack of resources.

7. Describe what is meant by a “foundation” species and identify one example. “Foundation” species is a dominant primary producer in an ecosystem both in terms of abundance and influence for example a tree.

8. Describe what can happen when a keystone species is removed from a community. Identify an example of a situation where this has happened.

A keystone species exerts strong control on a community by their ecological roles, or niches and are not abundant. If the keystone species is removed it would make their system be dramatically different or stop existing altogether. For example sea stars illustrate their role as a keystone species in intertidal communities. If the sea stars are removed, unless another species moves in to fill the niche, the prey species of the sea star would overrun the environment.

9. Discuss the differences between primary and secondary succession. Primary succession occurs when no soil exists when succession begins. Secondary succession occurs when begins in an area where soil remains after a disturbance.

10. Choose an example of primary succession (such as the sand dunes on Lake Michigan) and describe the changes in the plant communities and soil from the beginning community to the climax community.

One example of primary succession is the sand dunes on Lake Michigan. It was a struggle for the plant communities to evolve on sand. The dunes went through a complex process known as succession, in which natural communities replace each other. Each stage of plant succession created different microenvironments. The microenvironments were created by changes in temperature, moisture, and light intensity caused by plants and animals occupying the site. Succession and ecological change occurred rapidly in the dunes. Drops in lake levels expose sand spits or create new for dunes which were rapidly colonized by beach grass. Within one or two human generations the vegetation can change from beach grass to shrubs to trees. Storms and high lake levels can cause an even more rapid change in plant communities.

11. Discuss if “Smokey the Bear” is a good ecological concept for all communities (that is, always prevent all fires and never allow burning).

“Smokey the Bear” is not a good ecological concept for all communities (that is, always prevent all fires and never allow burning). Some biomes for example grasslands require fire to sustain their environment and ecology.

12. Most prairies experience regular fires every few years. Speculate on what might happen if the city prohibits the burning of the tall prairie grasses in the area for 25 years.

If the city prohibits the burning of the tall prairie grasses in the area for 25 years they would soon have shrubs and trees changing the ecology of the environment.