Gold Seal Lesson:
The Principle Of Incomplete Dominance

Copernicus Education Gateway

 

Subject:

Science

Grade:

 

 

9-12

 

 

ICLE Standards:

 

 

Life Science - Understand the molecular basis of heredity

 

 

Performance Task:

 

 

Eric works for an horticultural company that specializes in the production of new types of flowers and vegetables. To provide customers with plants that have favorable characteristics, Eric has to understand the basic rules of inheritance.
In snapdragons, the inheritance of flower color is an example of incomplete dominance. 

When red-flowered plants are crossed with white-flowered plants, all the flowers are pink.
Use a Punnett square to illustrate F 1 , the cross between a homozygous red-flowered plant with a homozygous white-flowered plant. Now cross two of these resulting plants, F 2 , and illustrate the cross in a Punnett square.

  1. What kind of offspring are produced in the F 1 generation? in the F 2 generation?
  2. Explain the phenotype ratio of the F 2 generation.
  3. How does the F 2 cross compare to the cross of two hybrids with dominant traits?
  4. Through examination of the data you obtained in the Punnett squares, what conclusions can be made concerning blending inheritance?

 

 

Knowledge / Skills:

 

 

Examine the foundations of genetics involving heredity and inherited traits passed on through generations, understand the gene-chromosome concept, and apply classical genetic studies (Mendelian genetics).  (s12)

Use expository writing skills in subjects other than English language arts.  (ela58)

 

 

Rubric:

 

 

4 Points  =  The student makes a complete response to all parts of the task. He/she shows an understanding of genetics and is able to construct Punnett squares to determine the genetic makeup of offspring when two "parents" are crossed. The student is able to translate this information into ratio form. The student is able to explain in writing the concept of blending inheritance and contrast it to dominant inheritance.

 

 

3 Points  =  The student makes an incomplete response to all parts of the task. He/she shows some understanding of the concepts involved, but can realize success only with a little coaching. The student has some difficulty expressing the idea of blending inheritance.

 

 

2 Points  =  The student displays little knowledge of the genetic concept of the task. Even with coaching, he/she is unable to successfully complete the task. The student is unable to express the results of the F 2 crossing in ratio form and has much difficulty expressing the idea of blending inheritance.

 

 

1 Point  =  The student does not complete the task and shows no significant understanding of the concepts involved. His/her work is disorganized and the Punnett squares are incorrect and/or incomplete The student is unable to use ratios to express the F 2 crossing and shows no understanding of blending inheritance.

 

 

Keywords:

 

 

LIFE SCIENCE
GENETICS
HEREDITY                
EARTH SCIENCE
EXPOSITION
RATIOS

 

 

Grades:

 

 

Kg [] - 1 [] - 2 [] - 3 [] - 4 [] - 5 [] - 6 [] - 7 [] - 8 [] - 9 [X] - 10 [X] - 11 [X] - 12 [X]

 

 

ICLE Application:

 

 

D

 

 

 

 

 

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