User:Charlotte E. Vogler/Notebook/Lab 2: Identifying Algae and Protists, Transect 2 on 7/3/14
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Lab 2: Identifying Algae and Protists on July 3, 2014
Introduction, Purpose, and Objectives
Today we observed samples of organisms from the hay infusion culture we made in a previous lab. This culture included samples from our transect at the Wesley Theological Seminary. Our objective was to practice using a dichotomous key to determine which organisms were located in our transect's ecosystem while also learning the characteristics of different algae and protists. We hypothesized that if organisms living near the top of the culture were more likely to undergo photosynthesis, while organisms living close to the bottom of the culture would be protists.
Materials and Methods
After allowing our hay infusion to mix for two days, we obtained samples from different locations, or niches, in the hay infusion. Samples were taken in order to find a minimum of three different organisms in each niche (top of the culture and bottom of the culture). For each organism discovered, a dichotomous key was used to determine what type of organism it was and also in order to make accurate drawings of the animals. A serial dilution was also made to create samples to be incubated in separate petri dishes containing agar and tetracycline.
Data and Observations
The hay infusion culture was full of soil, pine needles, leaves, and other plant life from the transect. Most of the packed soil and leaves fell to the bottom of the culture while the pine needles and loose soil floated on top. Samples were taken from each niche (top of the culture and bottom of the culture). In the top niche, the following organisms were found: chlamydomonas, euglena, and blepharisma, a paramecium species. In the bottom niche, the following organisms were found: multiple paramecium, chlamydomonas, and didinium.
Lab Manual Questions
1. Is there any apparent life on top of the liquid like molds or green shoots? Mold was forming only on leaves floating near to the top of the culture.
2. Why might organisms differ close to versus away from the plant matter? This happens likely because of the different environments organisms are most adapted to. Some organisms flourish while living on the grass, pine needles, and ivies, while others may be more prone to living in water or soil. It all depends on their natural niche.
3. If the hay infusion culture had been observed for another two months, what changes would you predict to occur? What selective pressures affected the community of your samples? If the culture was observed two months from now, it would be likely that most organisms would have been deceased or struggling to survive. This is because the ecosystem has been reduced to the size of a jar and nutrients and sources of survival would be difficult to come across. The organisms would be struggling to beat out other organisms for nutrition and perhaps resorting to consuming other organisms as a source of nourishment. Selective pressures would typically result in organisms who are able to photosynthesize surviving longer than those who rely on plant matter because eventually, sunlight would be the only remaining source of nutrients.
4. Choose one organism and describe how this species meets all the needs of life: Chlamydomonas
Diagram of Serial Dilution
Conclusions and Future Directions
We hypothesized that if organisms living near the top of the culture were more likely to undergo photosynthesis, while organisms living close to the bottom of the culture would be protists. This hypothesis was not proven correct. We only discovered one algae, which was found in both niches and protists were found in both niches as well.
At the end of the experiment, we left our hay infusion samples to incubate at room temperature for one week.