Blog Post #8- A Matter of Selection (Colin McCombs)

While studying our Brassica oleracea plants in the WGHS GOLD Main Garden me and my team discovered and observed a lot about the plants. We found that the shape size and texture of the different plants varied in the garden the most. Some of the plants had smooth thick ruffled leaves, some had hairy ruffled leaves ,and some had hairy flat leaves. All of the leaves also varied in size along with texture and collected this data by observing and taking measurements from the Brassica oleracea in the garden. 

This is a picture of the plant #1 leaf. From the picture you can see that this leaf is very smooth and thick and doesn't have any hairs or spines. It is a lighter green color with a blue hue and is very ruffled especially around the plant leaves edges. We measured the length of this leaf and it came in at 13.3 cm which is bigger than some of the plants but not as big as the ones you will see later.

This is a picture of the plant #2 leaf. This leaf is very different from the one above it isn't smooth or thick it is thin and has hairs along its stem, underside, and the top of the leaf. This plant has a darker green color and also is ruffled around its edges. This leaf was the shortest out of the plants that we measured and came in at 10 cm. 

This is a picture of the plant #3 leaf (sunflower). This leaf was different from the other leaves we observed as well. It isn't ruffled like all the other plants and has pointed jagged edges instead of the smooth curly ones. The sunflower leaf is very thin and has hairs along the stem, underside and top of the leaf just like plant #2 and has a light green color. This was the biggest out of the plants we studied and came in at 17.8 cm.

In conclusion we discovered that the leaves of the Brassica oleracea plants showed the most variation. We found that some of the leaves were bigger in size and had a different texture and shape, like the leaf from plant #1, and were smooth with a light green color and a blue hue. However, the leaf from plant #2 was a much darker green, and was smaller in length and had a hairy thin texture. The sunflower leaf was very flat and had lots of jagged edges . It was also a light green color, and was the largest out of all of the plants we measured and plant #1 was drastically smaller. This is why we think that the leaves expressed the most variation.

Next, me and my team decided to study the stems of the plants. I think that the stems of the plants showed the greatest range of variation in their size. The size of stems were different from each plant. Here is data that I collected in the garden for evidence of diverse stem size:

This is a picture of the stem from plant #1. This stem is very thin and brittle which is very flimsy and easy to break it is also a very light green color but doesn't run straight up the plant. This plant had the shortest stem measured at 26.2 cm.

This is a picture from plant #2 ,the plant with the smallest leaves. Even though this plant had the smallest leaves it had a very large stem measured at 1.32 meters (4ft 4inches). The stem of this plant was very light green textured and was very firm and hard to break. 

This is a picture from plant #3, the sunflower plant, which had the largest leaves that we observed. The stem of the sunflower plant was a yellow green and had sticky long hairs and was very hard and was hard to bend or move. The sunflower had the largest stem that measured in at 1.78 meters (5ft 10 inches).


I believed that the size of the stems showed the greatest range of variation among the Brassica oleracea plants. I think that this is true because you can see that the thin flimsy short stems are much different from the hairy sticky stocky stem of the sunflower. I believe that the large difference in the stem's size is why they showed the greatest range of variation


I think that the variation in the Brassica oleracea plants is the result of a few different factors. when you go outside and look at the garden, you can see that all the plants express some different traits. I think that what led to the variation in the garden is not a part of the process of selective breeding. Selective breeding, also know as artificial selection is when humans engineer new organisms based off of traits that we want that specific organism to express. I think that the variations in these plants are a result of something more natural. I believe that over time the genes of the plants slowly changed. Because the earth is constantly revolving organisms can constantly gain new traits, also know as adaptations these adaptations can help an organism better suit their environment which will help them survive. If these newly gained traits are beneficial to this organism, and its mate then then their traits can be passed down to their offspring. This is known as descent with modification. Overtime members of the same species with different adaptations can become so different that they either can't or don't want to mate with each other which is called reproductive isolation this causes them to become separate species. This happened with our Brassica oleracea plants. The natural variation of the plants led to speciation which caused them to be as different as they are now, but there are still some noticeable similarities, especially when it comes to their DNA. The base sequences in their DNA are 99% similar to each other. They aren't 100% the same because of mutations. When their is a mistake in the copying of a DNA sequence, it can cause a mutation. Most mutations don't do anything major to the plant, but some mutations can code for a different amino acid which will create a different protein and can then make some noticeable differences in the phenotype of the organism. All of these aspects can lead to the variations in the Brassica oleracea plants.

Me and my team observed the Brassica oleracea in the garden and learned that the stem color of our plants stayed the most consistent. I think this stayed the most consistent because of the chloroplast in the plants stems making it a light green color. Because all plants that use photosynthesis to turn sunlight energy into natural sugars have to have this green chemical inside their leaves and stems, this gives them their similar green to light green color.

A main way to get a characteristic or phenotype trait to appear different is through Natural Selection. If the plant or animal doesn't need a specific characteristic, this trait can be changed through Natural Selection. If a plant breeder wanted to get the body part or characteristic of a plant the breeder would need to acquire a Brassica oleracea that expresses that trait and make them have offspring. Eventually after many rounds of breeding the offspring will express the desired trait and you can breed these plants with the other plants that have these same desired traits. They will continue on producing the desired flowers until you or something disrupts the breeding cycle or they mutate and become reproductively isolated.