Artificial Selection Lab

Introduction / Purpose:
For this experiment, each lab group in our class was given 3 different kinds of seeds. Our job was to plant and nurture them for an extended time. The end goal of this experiment was to eventually get the plants to reproduce. We would do this by artificially selecting which plants would reproduce together once they had matured. The purpose of this experiment was to demonstrate how artificial selection works, and how offspring can be specifically selected to display certain traits. It also tested how well the students could conduct a long-term experiment.

Procedure:
1. Each group was given a length of wicking core, three pots, and a cup of fertilizer.

2. Cut the wicking core into three sections and put one in each pot. Be sure to pull them through the hole at the bottom of the pot.

3. Fill each pot with fertilizer. Each pot should be roughly three-fourths full.

4. Plant three seeds of the same species in each pot. The species are: "Purple Stem, Hairy", "Non-Purple Stem, Yellow-Green Leaf", and "Non-Purple Stem, Hairless".

5. Place the pots in the tray structure, making sure the wicking core has gone through the plastic sheet and can reach the water below.

6. Water the plants everyday until the plants grow to be adults. If you are leaving the plants for more than one day, be sure to give them more water than normal.

F1 GENERATION:

F1 Day 5

F1 Day 6

F1 Day 8

F1 Day 10

F1 Day 11

F1 Day 14

F1 Day 15

F1 Day 18

7. After about 2 weeks, our F1 Generation plants died and could not reproduce or make new seeds, So we were given "cheat seeds" of what the F2 Generation should have been; "Non-Purple Stem, Yellow-Green Leaf".

F2 GENERATION:

F2 Day 1

F2 Day 1

F2 Day 39

Analysis / Conclusion:

The purpose of the experiment was to observe the generations of offspring produced from cross-pollination with the three different types of seeds that were initially planted in the pod. The F1 generation, or the first generation of offspring, grew successfully. Primarily plants with yellow petals were observed during the weeks that the F1 generation was allowed to grow. This may be due to the gene for that phenotype being dominant with the Brassica plant species.

However, no growth was observed for the F2 generation. There are several potential reasons for these results. It is possible that since five seeds were planted within the same, small space, availability of resources was limited and the seeds could not thrive without more nutrients. Another potential reason is the experimenters not watering the pod enough to provide enough water for the seeds. In order to improve the experiment, it would be suggested to more carefully measure the amount of water that is given to the plants each day, as well as allow each seed to have its own pod to be planted in. In order to control the experiment more and better observe the effects of artificial selection, it is necessary to provide the seeds with the necessary nutrients to grow, so that any growth or lack of growth observed is due to artificial selection and not another factor.