Artificial Selection Lab

Artificial Selection Lab

Purpose

The purpose of this lab is to discover how the process of artificial selection is used on existing species--in this case, plant species--with varying characteristics to develop offspring with only the desired traits. By using fast-growing, lab-developed plants, we can more easily observe how artificial selection works across multiple generations.

Introduction

Artificial selection has led to many of today’s species, especially domesticated ones. The many breeds of dogs and cats were artificially selected for distinctive traits. Species of crops were also developed over many years for the most viable characteristics.

Fast Plants are plants developed by a professor at University of Wisconsin-Madison to be plants that germinate in a very short time period, only a matter of a couple of days. Not only do they develop so quickly, but they are also made to pollinate with only involvement by the researcher.

Methods

A wicking cord is threaded through the bottom of each of the three pots. Each of the pots are filled with potting mix until they are almost full. The soil is patted down firmly into each pot.

Plant six seeds into the respective pot of each type. Cover the seeds with a thin layer of soil and pat it down firmly onto the seeds.

Place the pots into the provided plastic pan, ensuring that the wicking cord extends to the reservoir below.

On the left: the three pots after the seeds were planted

Water the plants with liquid fertilizer every day. Take pictures of the three different plant varieties, observing changes in growth and plant height. Pay attention to the distinct characteristics of each plant variety.

   

Above: days five and seven of plant growth**

When flowers have developed on all of the three varieties, cotton swabs can be used to collect pollen from one flower and deposit it on another flower. Choose two varieties to cross-pollinate; the offspring of this are the testing population. The third variety would be self-pollinated as a control group.

  

Above: days fourteen and eighteen of plant growth**

After several days, seed pods will develop on the plants. Take the pods off of each plant. Be sure to label them according to which plant they came from.

Above: day twenty-four of plant growth

Allow the seeds to completely dry until they are yellow. Then, open the pods and remove the seeds. These are the seeds for the second generation of plants.

Plant these seeds in the same way as the first generation. Observe the growth of these plants over time until they develop the fully developed traits. The control group of the second generation should have the same traits as the first generation. The test group of the second generation should have combined traits from the cross-pollinated groups.

Data

We were unable to obtain accurate data about the artificial selection cross because the seeds of the second generation did not grow to full development.

Graphs & Charts

Graphs and charts were not needed for the analysis of this lab.

Discussion

The unsuccessful results of this experiment could have been due to a host of both environmental and experimental factors: lack of water, burying the seeds too deeply in the soil, too few seeds, crowding of seeds, etc. In alterations to this experiment for actual success, there could be several groups of the same three varieties so there are different opportunities for a test cross to be successful.

Although the results of this lab were not able to be analyzed, this process did provide great insight into how artificial selection is used to develop strains of species with certain traits. It also provided awareness of situations where artificial selection could be unintentionally manipulated. If plants of different varieties are too close together, pollen could be exchanged between their flowers.

Conclusion

We began the experiment being very attentive, our plants began to thrive and lived very well for a long time. We cross pollinated the three plants flowers and continued to water them until pods formed and grew to have seeds in them. Yet for some reason the pods the plants produced had very minimal seeds. To continue our experiment we planted what seeds we could scavenge from the pods after letting them dry out over the weekend.

**Note: With off days and weekends, the number of the day on which each stage of growth was observed was estimated.