Natural Selection

To complete your SLP, you will complete your analysis of the peer-reviewed article by Urakawa et al (2012) that described the influence of crude oil on two groups of bacteria, Eubacteria, Nitrosococcus oceani, and Archaea, Nitrosopumilus maritimus; that utilize different methods of metabolism.  Now that you understand the taxonomic and metabolic differences between these two species, think about how these organisms interact with their environment and how these interactions could potentially affect other populations of organisms.  As you prepare to complete this final component of the SLP make sure you think about the nutrients and chemicals that these organisms consume for energy, removing it from their environment, and produce as a byproduct, adding it their environment.  By both removing and contributing chemicals and nutrients to their environment, these organisms can alter the availability of nutrients for other organisms.

As we discussed on the Home page of Module 5, the success of individuals, and ultimately of populations of organisms as a whole, is largely determined by their ability to acquire resources from their environment to the extent that they can find a mate, reproduce, and pass their “successful genes” onto their offspring.   The term natural selection, describes the role of environmental pressures on determining the success of species.  Over long periods of time, the theory of natural selection helps us to understand how species have evolved.  Proceed through these brief tutorials developed by the University of California, Berkeley, to understand more about natural selection, and its relevance to your SLP:

Natural Selection

Follow the arrows and read the sections on Natural Selection at Work and What About Fitness?

Now complete your research on Nitrosococcus oceani and Nitrosopumilus maritimus using the resources below:

First, visit this website developed by Texas A&M University’s Department of Oceanography:

to learn more about the marine foodweb, and the relationships between microogranims and larger organisms that inhabit the oceans.

Now read the following article from the University of Washington

and this article from the University of Illinois, Urbana-Champaign,

to consider additional byproducts and nutrients that these microbes can contribute to the environment, thereby influencing the metabolism
of other species.

After completing your readings, address the following in a 2-3 page paper:

  1. What chemicals do Nitrosococcus oceani and Nitrosopumilus maritimus consume from their ocean environment?  How does the abundance of these chemicals influence their success and abundance?  What is the relationship between nutrient availability and natural selection, in general?
  2. What chemical byproducts do each contribute? (Be sure to cite the references above!) How does this relate to the “Greenhouse Effect?”
  3. If one group is selected for due to their ability to withstand an abundance of crude oil, what chemical offsets to the environment are possible?  How will this affect other organisms in this community?  Provide specific examples with references to support your ideas.

Assignment Solutions