EXPERIMENTAL SET UP AND BACKGROUND INFORMATION 

In CGS #2 students again worked with the Arabidopsis plant.  This time the focus was on a different part of the plant.  Instead of cotyledons,  students were crossing plants and observing the outcomes when they crossed plants that had either elongated leaves or wild type leaves.  

Like CGS#1 they also did three crosses:

• Elongated x Elongated 

• Wild type x Wild type

• Elongated x Wild type

OBSERVATIONS / DATA 

Although we collected large amounts of data  (students did five of each cross), the compiled data is what is shown below:

• Elongated  and elongated  also produced two outcomes

  • All plants were elongated

or

• • 75% were elongated and 25% were wild type

• Wild type x wild type produced one outcome 

  • All of the offspring were wild type 

• Elongated and wild type  produced two outcomes

  • All offspring were elongated 

or

• • Half the plants were elongated  and half were wild type 

CONCLUSIONS

The same conclusions as CGS #1 and also the following:

Claim #1 - The same patterns of inheritance exist for different parts of the plant 

Evidence:  The outcomes  observed for elongated and wild type leaves were the same as the outcomes for the pointed and rounded cotyledons in CGS #1 in the following ways:

• When two plants with the same version of the trait were crossed the following occurred in both cases:

  • All of the plants in the next generation were the same as the parents  OR

  • 3/4 of the next generation were like the parents and 1/4 were not 

• When two plants were crossed that had different versions of the same trait (pointed vs rounded / elongated vs. wild type) the following outcomes were observed in both cases:

  • All of the plants in the next generation were like their parents

  • 2/4 of the plants were like one of the parents

  • 2/4 of the plants were like the other parent 

Reasoning: The same patterns of inheritance were observed for different traits of the Arabidopsis plant, therefore the process that controls the way in which traits are passed from one generation to the next  must be the same for different parts of the plant, otherwise the outcomes would not have been the same.