Biodiversity and its Experiment

Biodiversity was an experiment performed by a 9th grade class in mid October 2013. The purpose of the experiment was to observe the difference in the amount of species found in each section of a small “pond”. In the small “pond” were three section which were the Surface, Middle and, Bottom Layers. Before starting the experiment, the class had learned about the meaning of biodiversity and how it impacts the Earth.

When the class engaged in the experiment, the students found that certain layers contained more species than others, thus biodiversity. In conclusion, the class found that the surface contained the most organisms. Even though the data varied between the groups of students, the class generally came up with the same conclusion.

Materials: 4 Pipets 9 Microscope slides 6 Blank glass coverslips 3 Gridded plastic coverslips Microcentrifuge tube Compound microscope

Procedure: Activity 1: First, the pipets were labeled “Surface,” “Middle,” and “Bottom” for collecting data from the three levels of the pond. Next, each pipet was used to take a sample from each level of the pond. After that, the students placed a single drop of the sample water on to the slide and then placed the cover slip on top of it.

Then, the individuals took turns examining the samples of each layer of the pond to identify the organisms on the sample. Using the dichotomous key provided the species of the organisms could then be identified. The students drew and labeled the organisms for each layer on to each Data Table in the Biodiversity packet. Activity 2:

On the basis of the results of Activity 1, a hypothesis was made on which layer of the pond would have the greatest biodiversity. The students then received a layer assignment from the teacher. After that, a clean pipet was used to obtain a small of water from the assigned layer. Next, 5 drops of the water sample along with 1 drop of Protoslo Quieting Solution were put in the microcentrifuge tube.

The cap was placed on the tube and then inverted many times to mix the contents. Using the same pipet, a drop of Protoslo and water mixture was placed on to the center of a slide. Next, a gridded coverslip was placed over the sample and then examined under the compound microscope. The students randomly selected a square of the gridded transparency that covered the sample and counted the number of organisms of each species seen in that square.

The data was recorded in Data Table 2. The students then repeated the random grid selection and recorded the results in Data Table 2. Two more samples were taken from the microcentrifuge tube. The results of the grid counts were added for all three samples. The total number of each type of organism found in each sample was estimated. The students then shared different data with each other and recorded class data in Data Table 3. The different data was added and the total was found in Data Table 3. The Diversity Worksheet was used to determine the species richness. Last, the Simpson index of diversity for the class data was calculated and recorded in Data Table 4.

Data: Surface Layer

Middle Layer Name Of Organism: Group 1: Group 2: Total (n): Spirogyra 1,944 648 2,592 Paramecium 2,268 3,402 5,670 Rotifers 486 162 648 Euglena 648 0 648 Volvox 1,944 324 2,268

= 11,826

Bottom Layer Name Of Organism: Group 1: Group 2: Total (n): Spirogyra 1,620 648 2,268 Paramecium 134 1,620 1,944 Euglena 324 648 972 Diation 1,086 0 1,086

5,298

In terms of the objectives, I found that the data was much larger than I expected. From background information I knew that there had to be a different biodiversity between each layer in the pond. My partner and I found that many other groups had some of the same data if not almost identical so we tried to find groups with different results. The experiment worked well in the sense of coming up with a valid answer as to which layer contained the most biodiversity.

In the Biodiversity lab report, the 9th Grade class experimented with different organisms from one pond under a microscope. They collected data from the three different layers of the pond to find the biodiversity of the surface, middle and, bottom of the pond. The class came to a conclusion of the surface having the most biodiversity among the pond. The groups may have found different results depending on how they did the procedure but they all mostly came to the same conclusion.