User:Andrea Lopez/Notebook/01/21, T5, Preparing and Plating Serial Dilutions and Hay Infusion Culture Observations using a Dichotomous Key/Entry Base

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Hay Infusion Culture Observations

Purpose The purpose of this lab was to examine and observe which organisms were present in our transect. By determining and identifying the differentiating organisms, we will be able to further analyze the content and environment our transect holds. In addition, further information about the organisms within the transect gives us a depend knowledge on eukaryotic and prokaryotic organisms and their preferred environment.

Materials and Methods To begin our observations, we took a drop of each niche within our hay infusion and placed it on a microscope slide. After that was done, a cover slip was placed over the sample. We then began our observations by placing the slide on the microscope and closely examining the various organisms that were found. To correctly determine the type of organism, we used a dichotomous key. To prepare for next week's lab, four tubes of 10mLs containing broth were labeled. Next, eight agar plates were attained to begin the plating (one containing antibiotics and one not). 100 microliters of the content within the hay infusion were added to the 10 mLs of broth. 100 microliters of the previous tube were then added to the next tube labeled 10^-4. This process was repeated to complete the next two dilutions. Once the solutions were prepared, a micropipette dispensed 100 microliters of the culture into the agar plate and spread with an inoculating tube. This procedure was then repeated with each tube so all eight agar plates contained a sample of each diluted solution.

Data and Conclusions The two niches identified within the hay infusion varied to a high extent. The bottom niche contained materials that were more dense such as soil, rocks, and some heavy leaves. In the top niche, a film of green mold covered the entire liquid. Perhaps the reason why the top niche did not contain plant material is because it is not dependent on plant features. In addition, mold grows at best capacity under airy conditions which could explain why there was mold closer to the surface of the container. Because the mold was at the top of the container, the smell of the content appeared to be a mixture of dirty sewage water and fertilizer. By observing the culture from both niches, we found that many of the organisms were motile. The organisms found in the top niche were Volvox, Blepharisma seculum, Euplotes patella and , Oscillatoria curviceps. Out of those four, all of them displayed a form of motility. Volvox displayed a rolling motion despite of the non-motile gonidia in the interior of the organism. Blepharisma moved by organisms specializing in motility. In addition, the organism contains cilia to assist in movement. Euplotes patella have a swimming-like feature and were extremely difficult to observe due to their fast movement. Lastly, the Oscillatoria curviceps moved by means of their microfibrils. In the bottom niche, we found Colpidium campylum and Nostoc azollae. Nostoc azollae moved by relatively short motile filaments called harmogonia whereas Colpidium did not display any motile features. By utilizing the Dichotomous Key, we found that Volvox, Oscillatoria curviceps and, Nostoc azollae all perform photosynthesis. More specifically, Nostocs perform photosynthesis by photosynthetic pigments contained in the cytoplasm. Volvox and Oscillatoria are common in the fact that they are both algae. The rest of the organisms seemed to obtain nutrients by means of specialized organelles such as vacuoles. Volvox displayed all five features that identify a living organism. Firstly, volvox use and receive their energy through photosynthesizing mechanisms. Their DNA is replicated during cleavage and is composed of numerous cells. Volvox is unique in that it can reproduce both asexually and sexually. Lastly, Volvox continues to evolve within each differentiating habitat. It can be predicted that in two months, the ecosystem within the Hay Infusion Culture will continue to grow due to the organism's individual mechanisms. For example, a symbiotic relationship between organisms will allow the ecosystem to continue to grow or obtain stability.

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