Introduction
Distribution patterns of organisms vary from organism to organism and they are dependent on various factors such as competition for resources. In this project, we will investigate the spatial distribution patterns of dandelions across an area of 1m2. Dandelions are considered as weeds when they appear on lawns and are reported to grow in almost all parts of the world.
Some people however, do not mind their growth as they consider them a welcome addition to their plates as a vegetable especially in Asia. There are claims that their leaves and stems have medicinal value and are known to contain a high level of potassium (Himmelman, 2008, p. 25).
The scientific name of the dandelion is Taraxacum officinale. Dandelion plants produce asexually; each plant produces seeds with no pollination and they eventually grow into an identical plant as the parent plant. They are tap rooted weeds that grow in areas with temperate climate all over the world.
It produces yellow flowers that stay open during the day and close down at night. The flower sprouts from a stem that is 2-15cm elevated from the main plant. Each plant may produce several flowers at a time. A full grown flower turns into a clock that holds numerous numbers of the fruits referred to as achenes. Each fruit (achene) has âhairsâ attached to it. This is to enable wind to carry each achene to far locations where it grows into a new dandelion.
In this project, we will look at two types of dandelions, the tall dandelions and the short dandelions. The tall dandelions have flowers with a stem as long as 17 inches and their leaves are 14 inches. The short dandelions have 8 inch flowers and 5 inch leaves. The tall dandelions grow in places with tall vegetation. They grow longer to enable them to access adequate sunlight (Himmelman, 2008, p. 13).
Dandelions grow almost anywhere as long as there is good soil which is frequently wet. They however are known to grow more amongst grass, tall or short. In well maintained lawns, they are considered as weeds. In this project, i chose a grass lawn that had been neglected for a couple of months.
The grass as expected had overgrown but the growth was irregular. Some patches had long grass while some had short grass. There were also other types of weeds that had grown. I chose dandelions because they were more than any other weeds present on the lawn and they were easy to spot due to their yellow flowers (Himmelman, 2008, p. 18).
Method
First, I divided the 1m2 lawn into four equal portions, each having an area of a quarter square meters (Thomas & Robert, 2008, p. 188). Measuring was required to ensure that the four portions were equal in size. This was accomplished by the help of a tape measure. First, the outline of the lawn was measured to ensure that it is exactly 1m2.
The boundaries marking the outline of the 1m2 lawn were marked. A half a meter was measured on each side and the half meter mark was noted. The lawn was then divided using the half meter markings on each side to produce 4 portions, a quarter meter squared each. The distinction between the four portions was done using thin poles that were erected around each portion.
For easier identification of the boundaries, a white coloured strip of cloth was tied at the top of each pole. This was to ensure that the boundaries can be clearly seen even from a distance. This whole process of dividing the lawn was done carefully so as not to step or bend any dandelions on the lawn as this could change the results. The distribution of dandelions on each potion of the lawn was then observed.
The observation process was not difficult as the dandelions were easily spotted by their bright yellow flowers and the distribution was easily notable. The exact number of dandelions on each portion was not obtained due to the large numbers of dandelions on the lawn. While at the lawn, the wind direction was noted since dandelion seeds are dispersed by wind, the direction could be a factor in the distribution pattern of the dandelions (Thomas & Robert, 2008, p. 188).
Results
The dandelions, as mentioned above were easily spotted. A diagram showing their patterns of spatial distribution was drawn. In the diagram, the position of the dots represents the position of the dandelions. Since this project is investigating two types of dandelions, red dots will indicate the location of the tall dandelions and black dots will indicate the position of the short dandelions.
As shown above, the dandelions were scattered randomly across the four portions of the lawn. The tall dandelions, represented by the red dots are seen to grow clustered around one point unlike the short dandelions. The short dandelions are the majority on this lawn. The arrow on the compass represents the general wind direction in the area where the lawn is located. The winds in this are is generally not strong wind, just a gentle breeze.
Discussion
From the results above, the distribution pattern of dandelions on this lawn is random. This conclusion is drawn because the dandelions are irregularly distributed all over the lawn. It is seem that the bottom left portion of the lawn had the lowest number of dandelions. This can be explained by the general wind direction in this area.
Since the wind blows in the North East direction, when the seeds of the dandelions are dispersed, most of them land on the portions further into the direction of the wind. It is seen that the top right portion of the lawn has the most dandelions plants; since it is further into the direction of the wind, a larger share of the seeds are dispersed to this portion (Thomas & Robert, 2008, p. 186).
As discussed earlier, the long dandelions grow taller in response to competition for sunlight with other plants. The long grass on this lawn had grown irregularly. This explains why the long dandelion plants only grew in certain places and not others. The places where the long dandelions were found are the places where the grass had grown longer and there was need for the dandelion plants to grow taller so as to access adequate sunlight (Thomas & Robert, 2008, p. 188).
1m2 was the most adequate size of lawn for this project and dandelions were the most appropriate plant. Dandelions grow very fast and within a short period, they can fill an entire location. They are easy to spot due to their bright yellow flowers. Investigation on a larger lawn size (larger than 1m2) would have been difficult especially in the partitioning of the land into portions.
However, the results obtained would have not been altered no matter what size of lawn was used. The pattern of distribution of dandelions is dependent on the wind direction for the dispersal of seeds and the kind of vegetation around the dandelion determines the size of the dandelion, either short or tall.
References
Himmelman, J., (2008). A Dandelionâs Life: Nature Upclose. New York, NY: Childrenâs Press.
Thomas, M. S., & Robert, L. S. (2008). Elements of Ecology. San Francisco, CA: Pearson Benjamin Cummings.