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Lesson Review

ETP Title:Natural Selection Activity with Introduced Mutations
Organization:
ETP Type:
Grade Level(s):10

Subject Areas

  • Science

California Standards

7. The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable over time. As a basis for understanding this concept: a. Students know why natural selection acts on the phenotype rather than the genotype of an organism. b. Students know new mutations are constantly being generated in a gene pool. 8.Evolution is the result of genetic changes that occur in constantly changing environments. As a basis for understanding this concept: a. Students know how natural selection determines the differential survival of groups of organisms. b. Students know a great diversity of species increases the chance that at least some organisms survive major changes in the environment.

Lesson Abstract:

 Lab  Activity: Natural Selection Activity with Introduced Mutations


      This Lab Activity engages students in a simulation of natural selection with the introduction of a mutation. They also will incorporate a DNA  electrophoresis gel to  "find" the mutations.  In the Lab  Activity a predator- prey scenario is repeated over 4 generations and then 2 mutations are introduced into the population. One mutation enhances the ability of the predator to catch its prey, the other hinders it. It is at this point that students will utilize a DNA gel to discover which mutation, if any, has occurred in their predator.  Students will show their ability to interpret a DNA sequence into mRNA and then amino acids. Following that they will interpret the type of mutation, insertion, deletion or substitution of a base.Using the changes to the predator, the activity will again repeat over 4 generations and a shift in the allele frequency for or against the mutation will occur. Students will visualize the factors that influence changes in a gene pool of a population, eventually leading to evolutionary changes.


 

The needs this ETP will fulfill in the classroom, teaching or school:

The connection between the ETP and Fellowship. :

Outline:

Connection to Fellowship: JGI is a user facilty that focuses state of the art sequenicng and analysis capabilities on on organisms that have potential in coverting biomass into biofuel. The lab I am working in makes libraries from DNA sent from collaborators around the world.  The ever changing world of Biotechnology is included in the standards of Biology, and the products that are avialable because of this technology. I will be relating some fo the the recent advancements in Biotechnology I have learned at JGI in my unit and include some of the techniques I have learned to enhance a specific lesson.

Need : Often I find that topics of evolution that are related to each other are preceived by the students as distinct ideas instead of a part of a whole idea.   My goal is to interrelate a series of Natural Selection activities to incorporate concepts of survival of the fitest, and the effect of  mutations on  the "fitness" of a individual in a population. This mutation could potentially result in a change in the frequency  of specific alleles in a population over time.  In this simulation, the students will be able to visualize and quatify the forces that shape and change a population's characteritics over time.

Objective/Outcomes:
Students will be able to experience and articulate the changes in an allele frequency in a population due to natural selection on favorable and unfavorable mutations.  In addition they will be able to make, understand and interpret information from an electrophoresis gel with dye markers.

Purpose
To simulate the effects of natural selection on generations of a predator  population with the introduction of a favorable and unfavorable mutation. 


Hypothesis
A mutation that renders a predator more “fit” will allow it to survive and pass on its genes to other generations resulting in a shift in alleles frequency in a population. 



                                     Teacher Information


Prior Knowledge: Before you begin this series of activities, you will want to be sure the students understand the following concepts.  If you wish you can stop in between activities and teach the concepts and techniques needed for the Electrophoresis gels before you finish the last activity.

  •    Students should have an understanding of how natural variation and mutations can determine an organism’s fitness for the environment. 
  •     Students should understand that overtime natural selection results in changes in the inherited characteristics of a population.
  •     Students should know how to interpret DNA bases to codons to appropriate amino acids. Also, they should be able to determine the type of mutation, substitution, deletion or insertion.
  •    Students should know how to run and interpret an Electrophoresis gels with differing ladders of simulated DNA.

 

Anticipation Set
You may want to show the students a short video clip called “Unhinged” found on the website called Teacher Domain. It shows how snakes have different adaptations for catching their prey.  After showing the video clip have students explore the connection between mutations, natural selection and adaptations.  Next explain that they will be doing an activity in which a predator will have a mutation that may or may not help them catch their prey. These mutations, if successful can lead over many generations to a change in the allele frequency and result in a favorable adaptation in a species.

Materials

  •   Insect Prey: Equal numbers of different colored but same size beans, pinto, red, black, brown, white. Two 1 lb. bag of each type of beans.
  •    Predator – prey’s environment: Multi colored wrapping paper, close to color of some of the beans
  •     Predator’s Bird Beaks: Spoon, Fork, Knives
  •   Stopwatch, Cups, ,Amino Acid Code
  •     5 different worksheets with instructions and data tables.
  •    Ingredients for   1% Agarose Gel , 4 different dye ladders, Electrophoresis Apparatus,  TAE buffer, pipette tips and Micropipettes  - can use Edvotek S- 49 kit $50.

Preparations by Teacher before Activities
1.    Make copies of all appropriate handouts
2.    Assemble materials for Part 1 and 2 or Natural Selection Activity
3.    Buy Kit Edvotek S- 49 kit $50.00, or close approximation. Need a to run at least 4 different ladders for the activity, in each gel.
4.    Bookmark on computer “Unhinged” video clip on website Teacher Domain
5.    Set up groups of 5 with a lab table or area to set up “environment” of wrapping paper. Wrapping paper should have colors similiar to some of the "prey" beans so that some are "camouflaged" while others are not.
6.    Be sure students have prior knowledge as described above.


 Schedule of Activities-Procedure
Day 1: Anticipation Set: Video Clip, Part One of Natural Selection Activity (no mutation)  See handout part 1: Natural selection activity for complete explanations


Day 2: Explanation of gel electrophoresis and students set up gel. May want to show students video clip on how to make, load an run a gel electrophoresis from the website http://learn.genetics.utah.edu/content/labs/gel/  To save time, the teacher can prepare the gels ahead of time so students only load them, run them, and get the data.  See handout Detecting Prey mutations with DNA Electrophoresis Gel for complete explanations


Day 3: Students are randomly assigned in each group one of 4 types of DNA banding pattern on the gel. Each banding pattern represents a stretch of bases found on their handout developed by the teacher.  They are to use the bases to find a string of amino acids. These will correspond to a beak phenotype. They also will identify the type of mutation, point, deletion, substitution etc. See handout  Mutations in Beak Shape in a Predator population for complete explanations


Day 4: Part two of the Natural Selection Activity with the Mutations. They will use their new beak shape in the Natural Selection Activity.  See handout Part 2: Natural Selection activity with mutations for complete explanations


Day 5: Class discussion of questions included in the activities.  Assessment:  Written Conclusion of Week’s Activities. See handouts Student Assessment for complete explanations



 

Keywords:

Natural Selection, DNA Electrophoresis Gel, Mutations

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