Student Blog Post Assignment #9: A Matter of Selection

Jacob Sweet

1/12/15

Period 5

Blogpost Assignment #9

     The part of the Brassica oleracea plants that has the most variation is leaf shape. There are long smooth leaves, leaves with ruffles at the end of them, and almost circular leaves.

The plant with long leaves

The plant with round leaves

The plant with ruffled leaves

The part of the plants that has the most range is their height. The shortest plant (that also has round leaves) is the one that looks like purple cabbage which stands at 10 inches. The tallest plant is a yellow flowered plant with few leaves at its bottom and is about 42 inches tall.

The tallest plant

     There is so much variation in the Brassica oleracea plant because it was naturally spread to many different environments that it had to conform to. There were probably also a few mutations that survived that became a common new phenotype and many natural variations, adding to the large variation. In addition, things like plant sizes and color could have been changed by farmers to create more desirable characteristics. Farmers are able to do this through artificial selection and selective breeding which slowly changes the species' traits and gene frequencies through many generations. This works because of descent with modification.

     The anatomy of the Brassica oleracea plants that is mostly the same between all of the plants is their color. All of the plants (except for one purple one) are slightly dark green. However, a few are a lighter shade of green but that does not affect the majority much. I think this part of the plant did not change much because the color does not affect the plant's survival or amount of reproduction.
     To change a characteristic or body part of a plant, a farmer would have have to selectively breed for many generations. First, they would have to plant a vast amount of plants and chose the one with the strongest desired characteristic. Then, that plant would be allowed to reproduce many times and the "best" plant from it would be taken and the process would repeat. After many times of doing this, the wanted characteristic would become more common and stronger (or lighter, darker, larger, etcetera).