Solanum tuberosum

Solanum tuberosum

Solanum tuberosum or the potato is a much different plant than I had originally thought. When I first got the potato as my organism, I thought that I had an easy but boring organism. Potatoes are not what I had originally thought. The main thing that I learned about them is that the vegetable part of the plant people eat is not a root. It is actually part of the plant stem. The vegetable part of the plant stores food for the plant. They are usually found below the plant (Potato). Another thing that I learned about the potato is where they are found. I thought that they were grown only in the Idaho region of the United States and in Ireland, but R.J. Hijmans and D.M Spooner proved me wrong with experiments that they did with potatoes. They did experiments across the globe that showed the variety of potato species that could be found in a country. They also went on to show where species could be located and how far apart they were from other species. (Hijmans 2001)

Solanum tuberosum is part of the Plantae Kingdom, along with all the wild species of potatoes (Potato). This Kingdom consists of all the plants in the world. They range in reproduction from being asexual to reproducing with pollen or spores. Most of the plants are autotrophic. They produce their own food by photosynthesis. Organisms in this kingdom have created a way to defend themselves. Some plants use thrones while others use toxins. The potato has all of these parts to its life (Potato). It reproduces using a pollination system and a flower (Potato). The potato also uses photosynthesis to create its food (Potato). It stores the food that has been made in the tubers food-storing bodies underground. This is the actual potato vegetable (Potato). Solanum tuberosum has some defenses that it uses. It has sticky leaves to keep animals from trying to eat the plant. It also stores its food underground to keep the organism alive during harsh climate changes or periods when it cannot make enough food (Potato). The potato also has a very wide range of land that it lives in (Hijmans, 2001). This can go from the Rocky Mountains all the way down into Chile and Peru in South America, and they are usually found in the Valleys of these mountain ranges that are in these areas (Hijmans, 2001). The experiment by Hijmans and Spooner expanded on the knowledge of not just Solanum tuberosum, but potatoes in general, making it very important to my species (Hijmans, 2001). They were able to give facts that were once unknown about potatoes (Hijmans, 2001).

Hijmans and Spooner wanted to find out more about the diversity of the potato plant and where different species grow and under what conditions. They also wanted to know how certain regions of land affected the number of plants and species. They ended up doing a research experiment that would help them find this out. To find this out they went did 16 data collecting expeditions in 12 counties, and would first go out and find a potato species and mark it on a chart. After they had done this they would then go around the potato and mark off an area of 50 km radius. Once this was do they would go out over the marked off radius and count the number of potato plants and count the number of different species that were inside this radius. This was the first study to show the connection between closely related crop species and the environment in which they are found using the GIS system, or geographic information system which gives information about the geography of the land that the experiment is being done. It also was unique in the wide variety of geographic regions that were incorporated into the study. This would allow them to be the first to compare the different species of potatoes that grow all over the world by where they live and how many other species could be found in the area around the particular species. (Hijmans, 2001)

In the results, Hijmans and Spooner found out that wild potatoes grow in 16 different counties, and out of these 16 countries, Argentina, Peru, Bolivia, and Mexico, accounted for 88% of all the potato species (Hijmans 2001). The results also showed that Peru has the highest number of species (93), which is 47% of all the total wild potato species (Hijmans 2001). They also have 15 of the 17 potato species that only occur once in the data from the experiment (Hijmans 2001). This can be seen when they put all the data collected into TABLE 1. This made Peru the best place in the world for finding the most diverse populations of potato plants.

When Hijmans and Spooner gathered the results from the area of distribution data, they found a few interesting things about the potato plant. They found that most species of potato only live in one country. However they did find that 39 species lived in more than one country. Most of these plants were found in neighboring countries. They found that the most countries that one species was found it was five. This only happened one time. The next closest species was found in four different countries. This happened twice. The average greatest distance between two plants of the same species was 411 km. This means that most of the plants of any species are located within a 411 km radius of each other. (Hijmans 2001)

Another part of Hijmans' and Spooner's experiment was to see the distribution of the potato plants based on latitude and altitude. They said that potatoes are found between the latitudes of 38 degrees North and 41 degrees South. They also said that most of the species are found between 8 degrees South and 20 degrees South, and around the 20 degrees North latitude line. This means that the tropical highlands are the best area to find potatoes, but the Southern hemisphere has more potatoes than the Northern hemisphere. (Hijmans 2104)

The altitude that was best suited for potato growth was found to be between 2000 meters and 4000 meters. The average elevation of a potato was found to be between 2770 meters and 2890 meters. The experiment found that 91% of potatoes were found above an elevation of 1750 meters. The experiment also said that 75% of potatoes appeared below an elevation of 2300 meters. Most of the potatoes that were found in the lower elevation were from the hills and plains of Brazil, Mexico, Paraguay, Uruguay, USA, and Argentina. (Hijmans 2107)

This can be better explained by the graph and diagram that Hijmans and Spooner have made in their report. The diagram (Fig. 4) is of the Western Hemisphere. They have shaded in the areas of the hemisphere in which the potatoes were found. The area with the least number of potatoes species found is shaded in with blue. The middle range of potatoes species found is shaded in with green. The area with the most species of potatoes is shaded in with red. The graph (Fig. 10) shows the number of species found at different latitudes. The first rise in the graph shows the number a species that would be found in the Southern Hemisphere. The spot in the graph that flattens would represent the part of the world around the Equator. The second rise in the graph would represent species found in the Northern Hemisphere. Both of these charts show where you can find the greatest diversity of potato species. (Hijmans 2001)

The next three graphs show how many species were found in the 50 meter grid cells. The first one (Fig. 9) shows the number of species that were found in each grid cell. For every grid cell they made they found a certain number of potato species and that number is recorded on the graph. The second graph (Fig. 2) shows how far between plants of each species were when they were found. The third graph (Table 1) shows how many species and rare species were found in each country. These graphs and table are important to the experiment because they show the diversity of one type of potato species in the overall main graphs above them. This will help explain the graphs above by showing how rare a species is or how easy it is to find that species. (Hijmans 2001)

After reading this experiment and getting more information about potatoes, I have found that potatoes have a greater range in which they can live and survive in than I had originally thought. In fact, it's a much greater range in which they can live and survive in. I have found from the experiments done by Hijmans and Spooner that the reason why this is so is because of the elevations and latitudes that potatoes live at. The mountain ranges that go down the West Coast of South America make a perfect habitat for potatoes. Hence why there are the most species found here. Figure 4 shows this in an easy to read map. The experiment also has shown me that not all potato species are the same. They vary by where they live. This would also be due to the environment in which they live in. Most of which live in valleys of mountain ranges when I thought they lived on top of the mountains. Potatoes are a lot heartier of a plant and more dispersed than I had thought.


Hijmans, R.J., Spooner, D.M. 2001. Geographic Distribution of Wild Potato Species, American Journal of Botany. 88: 2101-2112

Potato. [Internet]. [cited 2010 Feb 7]. Available from:

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