A Matter of Selection by William Mahnke

All of the plants in the garden have grown a lot in the past few weeks.  However, as they continue to grow, they variations in their appearances.  The characteristic of the brassica oleracea plants that seems to exhibit the most change is the shape and color of the leaves.  As you see in some of the pictures, some of the plants have what you would think of stereotypical leave shapes and colors.  They have the classic green with a white stem and the leaves are a round shape.  These qualities however change as we look at other plants.  As you see in the second picture, the color of the leaf is a darker green then the first picture.  Not to mention, it has a purple stem and the shape of the leaves are very jagged with an overall shape of a round triangle.  Not only can the shape and color of the leaves change but the size as well.  The length of the leaves in the first and second picture are in order  about three or four inches and five or six inches.  Also, the width of these are small, both are about one to two inches wide.  In contrast, the third picture shows leaves that are much bigger.  They're average length are about eight inches while they're about four inches wide.  Other than these pictures, there are multiple different leaf shapes, sizes, and color.  The quality that showed the greatest range in variation was by far the height and diameter of the main stems of the plants.  Unfortunately, I don't have any pictures of the measurements, but we still did measure the plants, our type of plant the brussel sprout.  The first brussel sprout plant that we measured we got a height of 8.5 inches and the diameter of the stem was about two inches.  Additionally, this plant showed variation in the lengths of leaves and it had numerous large brussel sprouts already growing.  The second plant that we measured we got a height of 14 inches and the diameter was only one inch.  This one different have much leaf variation and had small Brussel sprouts growing.  Now these results were only for one type of plant in our garden and they were still pretty different height and had a little change in diameter.  So imagine the difference there would be if we measured a bunch of other plants.  It was certain that plant height showed the greatest variety.

Our garden has a lot of variability in its plants because of something called traits.  These traits are the results of genes, a unit of genetic information that is passed on from a parent or parents to their offspring.  These genes, which create the genotype, also code for the phenotype, or physical appearance of an organism.  These phenotypes are the variations in the looks of the plants in our garden.  Now Brassica oleracea, the type of plants we're growing in our backyard.  As a whole, brassica oleracea is a plant species.  In biology, when a species of an organism has different genotypes and phenotypes, that can often be describes with term of natural variation.  This term, natural variation links to another few terms, artificial selection and selective breeding.  Brassica oleracea involves plants like brussel sprouts, cabbage, and other numerous vegetable.  So in the food world, people who are growing these plants want the most out of their harvest.  So often what they do is to find the best traits for a certain plant and then to modify plants so that they have that trait.  This is the terms that I mentioned earlier, artificial selection and selective breeding.  This idea of producing food with genetically modified organisms (GMO) is very controversial.  The last thing I wanted to talk about in terms of the variation is mutations.  Usually plants get the genes of their parents which is descent with modification.  However, sometimes there is a mix up when the DNA is being replicated which results in a mutation.  This leads to an organism with a special trait, such as an albino alligator or having an unusual amount of legs.  Some mutations are harmful, but not all of them.

After talking about lots of variation in the garden, I want to talk about something that changed not so much compared to other traits.  The trait I'm talking about the structure of the veins in the leaves of the plants.  If you look at the pictures above and more pictures below, you see that everything in the anatomy of the plant changes except for this, at most minimally.  The usually structure of the veins includes the pattern of a main vein down the middle of the leaf with smaller veins pulling off to the side, similar to humans.  What's also similar to humans is the purpose of the veins in the leaves.  The purpose of these veins is to carry water and minerals to parts of the plants, like how humans have veins to carry blood to and from parts of the body.  Here are more pictures that show the similarities in the structure of the veins.

Finally, I'm going to be talking about how plant breeders would change the look of the structure of the veins in the leaves to have a much wider variety of appearances.  The easiest and most simple solution for them would be to do something that I mention earlier which is artificial selection.  Artificial selection nowadays is used commonly to increase the size of foods for consumers.  These plants are GMO's or genetically modified organisms and are argued to cause bad diseases, such as cancer.  For what these plant breeders want in this scenario though, there wouldn't be any of that included or mainly talked about.  Instead, the plant breeders would look at the genes for the veins of the plant and try to change them.  Normally, plants would inherit their genes from their parents.  However with this, the plant breeder would just change the genes to what they would want so the veins would change when the plant grows.  So if this were to actually happen, in about five to ten years you would probably see the different structure of the veins in the leaves.