User:Alison M. Mariano/Notebook/Biology 210 at AU

1/28/2015
Observing and Identifying Organisms With the Use of a Dichotomous Key
Purpose
The purpose behind this lab was to understand how to use a dichotomous key and be able to apply it to living organisms found in our assigned transect. The importance of identifying organisms with the help of the dichotomous key from the Hay Infusion Culture is to better understand the ecosystem that is American University. By understanding the organisms of an environment, scientists can better comprehend what other organisms would thrive there. Also, another purpose of the lab was to prepare for the following lab by creating serial dilutions from the Hay Infusion Culture. A hypothesis that could be created from this experiment is that if organisms were identified from the Hay Infusion Culture, then it could help better understand the environment which it came from.
Materials
The materials use in this lab were…
- a microscope
- dichotomous key
- already known organisms
- Hay Infusion Culture
- Notebook
- Pen
- Lab Manuel
- micropippetor
- Four nutrient agar plates
- Four nutrient agar plates with tetracycline
- A sharpie
Methods
Procedure 1: The first procedure of this lab included learning how to use the dichotomous key. To start learning how to use the dichotomous key, wet mounts of known organisms were made. They were viewed under the microscope with the objective lenses of 4X and 10X, rather than 40X because many organisms were moving too fast to be seen under this lens. Then, the dichotomous key was used to determine the identity of the organism by following the questions on the key.

Procedure 2: The second procedure consisted of using the Hay Infusion Culture to identity organisms from the assigned transect. The Hay Infusion Culture was brought over to the lab station and inspected for smell and appearance. After an initial observation was made, samples were taken from two different niches in the culture. From these two different niches, wet mounts were made to identify some of the algae and protists with a dichotomous key. Three organisms were identified from each sample.

Procedure 3: After procedure 2 was completed, preparations for the next lab were made. These preparations were made by the creation of nutrient agar petri dishes. Four test tubes were labeled 10-2 , 10-4 , 10-6, and 10-8. Next, all the plates with tetracycline were labeled “tet,” as well as labeled 10-3, 10-5,10-7, and 10-9. The Hay Infusion Culture was then stirred to mix up the organisms. 100μL was added to 10mLs of broth in the test tube of the 10-2 test tube. Then 100μL was taken from the 10-2 test tube and placed in the 10-4 test tube. This continued until the 10-8 test tube was filled. To put the serial dilution on the plates, 100μL were pipetted from the 10-2 onto the 10-3 plates (both the nutrient agar plate and tetracycline). This continued for the 10-5,10-7, and 10-9 plates; the 10-5 was filled with the 10-4, 10-7 was filled with 10-6, and 10-9 was filled with 10-8. The plates were then incubated at room temperature.

Data & Observations
Smell of the container: horrible, garbage-like, not rotten egg like)

Visual Observation:
Top of the jar → grass, clumps of dirt, surface almost looks impenetrable (like when you crack ice), some green grass poking through the top.
Middle of Jar → nothing really floating there
Bottom of Jar → grass, sediment of dirt sunk on the bottom, darker colored water towards the bottom.

Sample 1→ taken from the top of the jar in the center
Some of the type of organisms found in this sample were colpidium (55μm), Paramecium Aurelia (120μm), and a round, squished organism that could not be identified with the dichotomous key.

Sample 2→ taken near plant life at the bottom
Some of the type of organisms found in this sample were colpidium (50μm), a tiny single celled organism that was identified as chlamydamonas (6μm), and Gonium (20μm).

Conclusion
Since Colpidium was found in both samples taken (the one taken near the top of the jar and the bottom of the jar) it can be assumed that this transect retains a lot of water since colpidum is mainly found near water sources. Since there were no streams or lakes near this environment, the recent weather of snow and rain could have impacted it. From this lab the hypothesis was supported; a better understand of the environment could have been concluded by discovering the types of organisms in the transect.
AM

1/25/2015 Observing a Niche at AU Purpose: The purpose of this lab was to observe a 20 by 20 meter area of land on the American University campus that was defined by four popsicle sticks. Five groups were created and assigned to five different areas throughout American University. These observations that were made included general characteristics such as topography, location in regards to the campus, and biotic and abiotic features. Once these notes where taken, a Hay Infusion Culture was created for use in the next lab in order to observe protist and bacteria life from the transect. My group was assigned to transect number 5, which can be found on the main quad near the Eric A. Friedheim Quadrangle benches. Inside this transect was a grass area that included mulch, bushes, and some stone structures such as tiles, benches, and a wall. After observing the environment, I hypothesized that this area would lack wildlife since it is heavily populated by students as well as making the assumption that since it is well maintained by American University staff members it will constantly look very manicured. Materials - transect 5 (Eric A. Friedheim Quadrangle benches) - a notebook - a pencil/pen - sterile 50 mL conical tube - soil and vegetation sample - plastic jar - 500 mLs of deerpark water - graduated cylinder - 0.1 gm dried milk - tape for labeling purposes - balance for weighing Methods: The first procedure completed in this lab was the assignment of a transect to each group by the lab instructor, in my case number 5. Next, the lab instructor showed us to our designated area. From there, a notebook and pen were used to make observations about the topography, location, and biotic and abiotic features. A rough sketch was made of the area that included defining characteristics of the transect. Next, the lab instructor gave each group a 50 mL conical tube that was used to take a soil and vegetation sample. On the sketch below, the area where the sample was taken is indicated. The final steps of this lab included making a Hay Infusion Culture. Once back in the lab, 12 grams of the soil and vegetation sample were weighted with the use of a balance. Those 12 grams were then placed in a plastic jar along with 0.1 gm of dried milk and 500mL deerpark water (with the use of a graduated cylinder). With all the contents present in the jar, it was firmly shaken and then placed to rest on a table in the back of the lab. Data and Observations: The transect of my group was located on the main quad, near the stone structure that says Eric A. Friedheim Quadrangle. With my back to Hurst Building, facing Battelle the transect is the first corner of the stone structure. The topography of the area included bushes that lacked leaves (dead looking), many brown leaves scattered around the grass, mulch, weeds, stone tiles, benches, and a stonewall. There was, in fact, a sad looking fork found in the area. However, the space was mostly vibrant green grass, with a small portion being the stone structures. The sample was from the mulch and bush area. A list of biotic and abiotic characters can be see below….

Biotic - grass - bushes - leaves - squirrels - insects abiotic - mulch - snow - benches - tiles - soil - trash (sad looking fork) Conclusion: The observations taken from the area can help to further understand what type of environment it is within our ecosystem. With the help from the Hay Infusion Culture to see what type of organisms are present, are hypothesis can be supported in future labs once the results are conclusive. However, these observations on location and topography will further help my group to understand the environment. A.M.

1/21/2015 To all those who are lost upon using this website, I suggest reading the lab manual. A.M