Assignment: Natural Selection and Guppy Evolution

According to the theory of natural selection, organisms with traits that give them a greater chance of survival are more likely to pass these traits to offspring than organisms whose traits are not especially suited for survival. When Charles Darwin sailed on his 5-year-long voyage onboard the HMS Beagle, he recorded many observations of nature. Among these records, Darwin noted variations in beak shape and size among the finch populations throughout the Galápagos Islands.

Scientists who studied these beak variations realized the differences were not random, but related to the environment in which the finches lived. They discovered that finches tended to have beak types that made it easier for the birds to eat the foods growing in their particular environment (Belk & Maier, 2013). In what type of environment might finches with large, strong beaks have a greater chance of survival than finches with small, pointed beaks? Why might the finches with the smaller, pointed beaks be more likely to survive in a different type of environment?

Like Darwin and other scientists, biologist John Endler was interested in learning how environmental changes might influence the expression of advantageous traits in particular populations. Endler applied the principles of natural selection when he developed an experiment to study changes in guppy populations. He placed guppies in different environments and predicted how the fish populations would change in order to survive in those environments. For this week’s Assignment, you perform a virtual experiment based on John Endler’s experiment. Like Endler, you hypothesize how guppy populations will change to improve their chances of survival. You complete and submit a lab report for this Assignment.

To prepare for this Assignment:

• Review Chapter 12 “An Evolving Enemy” and focus on the following:
  • What the theory of natural selection asserts
  • What evidence supports the theory of natural selection
  • How the theory of natural selection relates to the theory of evolution
• Log on to MasteringBiology (see the Media section of the Required Resources) to review the animation “Principles of Evolution” and focus on the relationship between natural selection and evolution.

The Assignment:

By Day 5

1. Print and save to your computer the Natural Selection Lab Report document from the Natural Selection Virtual Lab. You may complete this report by hand as you complete the lab; however, by Day 7, you submit an electronic version of this document for your Assignment.
2. Complete the Natural Selection Virtual Lab. See the Required Resources section for the link to this activity.
   • Fill out appropriate sections of the Natural Selection Lab Report as you complete the lab. You may complete the analysis and conclusion sections of the lab report after you exit the virtual lab.

Questions about this Assignment? Post the questions in the Contact the Instructor area, so all class members may benefit from the Instructor’s response.

Refer to the Week 5 Assignment Rubric for grading details.

By Day 7

Following the instructions below, submit your Assignment. In order to receive full credit, all Assignments are due on time. Should you encounter an unanticipated and uncontrollable life event that may prevent you from meeting an Assignment deadline, contact the Instructor immediately to request an extension. Contact information for your Instructor can be found under the Contact the Instructor area. For a full description of the late policy, please refer to the “Policies on Late Assignments” section of your Syllabus.

Submission and Grading Information

To submit your completed Assignment for review and grading, do the following:

• Please save your Assignment using the naming convention “WK5Assgn+last name+first initial.(extension)” as the name.
• Click the Week 5 Assignment Rubric to review the Grading Criteria for the Assignment.
• Click the Week 5 Assignment link. You will also be able to “View Rubric” for grading criteria from this area.
• Next, from the Attach File area, click on the Browse My Computer button. Find the document you saved as “WK5Assgn+last name+first initial.(extension)” and click Open.
• If applicable: From the Plagiarism Tools area, click the checkbox for I agree to submit my paper(s) to the Global Reference Database.
• Click on the Submit button to complete your submission.

http://mym.cdn.laureate-media.com/2dett4d/Walden/BIOL/1001/CH/mm/virtual_lab_3/index.html