User:Esha B. Dholia/Notebook/Biology 210 at AU

Hay Infusion Culture Observations - January 22, 2015

Purpose: The purpose of this lab was to practice using a Dichotomous key to identify unknown organisms, and then to use this knowledge as well as an understanding of the characteristics of algae and protists to identify and examine the algae and protists from each group's own transect.

Procedure I - Using the Dichotomous Key: To become comfortable with the Dichotomous lab group was to make a wet mount of known organisms and observe them under the microscope at 40x objective. Then, a single organism had to be focused on and described by its size, shape, and various features. A Dichotomous key was then obtained and used to confirm the identity of the known organism by following the diagrams.

Procedure II - Hay Infusion Observations: Each group brought the culture back to their work areas to note any scents and describe the cultures' appearances. Then, each group took two samples from different niches of the culture, making sure to include some plant matter, and prepared two different wet mounts. Then, observing the slides under the microscopes, each group used the Dichotomous key to determine which algae and protists were present. The group drew pictures of the organisms observed and recorded their size. Each group was responsible for finding at least 3 different organisms from each of the two niches.

Procedure III - Preparing & Plating Serial Dilutions: Upon completing the Hay Infusion, a serial dilution was to be plated, which would allow prokaryotic organisms and possibly fungi from the culture to be observed. To do this, 4 tubes of 10 mL sterile broth were labeled with 10^-2, 10^-4, 10^-6, and 10^-8. Four nutrient agar plates and four nutrient agar plus tetracycline plates were then obtained. One plate from each of the groups was labeled with 10^-3, 10^-5, 10^-7, and 10^-9, with the tetracycline plates labels prefaced with "tet." Then, using a micropipettor, 100 microliters of the culture was added to the broth in the 10^-2 tube. The tube was then mixed thoroughly. One hundred microliters of broth from the 10^-2 tube was added to the 10^-4 tube, and swirled well. This was repeated to make the 10^-6 and 10^-8 dilutions. To plate these dilutions on the agar plates, 100 microliters from the 10^-2 tube was pipetted onto the plate labeled 10^-3. The sample was carefully spread on the plate, and the procedure was repeated on the 10^-3 plate containing tetracycline. This process was repeated to add the 10^-4 dilution to the 10^-5 plate, the 10^-6 dilution to the 10^-7 plate, and the 10^-8 dilution to the 10^-9 plate. The plates were placed on a rack to incubate at room temperature for one week. The process is depicted below.

Data & Observations: Upon bringing the culture back to the table, it was noted that the culture had no scent and had taken on a brownish color. There was dirt floating in the culture at the bottom, and a thin brown film coated the top of the culture as well as the sides of the jar it was in, but there were no apparent signs of life. The first sample was taken from the top of the culture, where a cloudy film of dirt was noted. Three different organisms - chilomonas, colpidium, and paramecium aurelia - were observed. Each of the organisms appeared to be moving quickly and had some sort of mechanism to propel it along. The chilomonas and paramecium both had cilia all over their body, while the colpidium had two flagella. The three organisms were protozoa, because they did not have any green coloring and therefore could not have been photosynthetic organisms. The colpidium was oval-shaped and 51 micrometers, the chilomonas was 22 um, and the parameciumm was 156 um. The following is a picture of the site where the paramecium was seen:

The second sample taken came from the soil at the bottom of the culture. Here, a peranema, arcella, and paramecium bursaria were identified. The peranema and paramecium were both more motile than the arcella, which was creeping slowly around the sample. However, none of the organisms were algae; they were all clear in color. The arcella was 63 um, the paramecium was 156 um, and the paranema was 45 um. Pictured below is the sample of soil where the peranema was seen:

Conclusions: This lab demonstrated the diversity of organisms in niche, even though the niche was so small. Organisms differ where they are, if they're closet to plant matter or not. If organisms are closer to plant matter, it's likely they themselves are photosynthetic algae and produce their own food. As with the organisms in this niche, because much plant matter was not present, the observed organisms were all protists. The arcella, like all the organisms, satisfies all the needs of life: it has to acquire energy to survive and reproduce, which it does through consumption of nutrients externally. It's a unicellular organism and has its own genetic information, which allow it to stay alive. The arcella reproduces asexually by replicating its genetic information and then passing down identical versions of it to offspring, and overtime the arcella likely evolves, based on mutations in its genes and how adapted the protist is to its external environment. If the culture were to grow for another two months, it's possible plants would actually grown, seeing as the soil sample was taken from a garden, but it's also possible the soil would continue to sit and disintegrate at the bottom of the culture. Those communities within the culture that are reliant on the large chunks of soil at the bottom would be most affected by this and would no longer have the soil as a mechanism to cope. Selection would weed out those organisms that have low fitnesses and are not well-adapted to the environment.

• Esha B. Dholia:

1.27.15 Good first entry. Missing some information eg. the Hay infusion set up. The transect was 20Ft by 20Ft. We will work on uploading pictures this week. SK

Initial Transect Observations & Notes - January 15, 2015

Purpose: This lab is an ongoing experiment, in which a particular transect of land and its ecological diversity on the American University will be observed by a group of students for several weeks. The purpose of this lab is to take note of the features of that particular transect in order to begin conceptualizing the immense diversity present within a single ecosystem.

Materials & Methods: The group was assigned transect 4, one of the five 20x20 ft parcels of land students in the class will be responsible for observing over a few weeks. In terms of what could be variable in later observations of this transect, the weather should certainly be taken into consideration; because data is being gathered in the winter, the organisms observed on the transect and their number could vary from what's seen in this same transect of land during different times of the year. The group was responsible for noting all aspects of this transect of land, including its situation, biotic and abiotic factors, and other characteristics. Upon completing the observations, the group collected a 50 mL sample of soil and ground vegetation in a sterile conical tube - meant to represent the transect - to make a Hay Infusion culture.

Data & Observations: This lab group was assigned transect four, which is located within the American University community garden next to the tennis courts, towards the back of the campus. Transect 4 is located in a relatively relatively isolated area, though it is certainly well-kept and tended to often. The transect is located on a flat piece of land, and is fenced off. Pictured below is an aerial-view diagram of the transect.

The four beds appeared to be well-watered, though they did seem to be exhibiting any signs of exceptional plant growth. Certain vegetables had better growth than others.

The biotic, or living, factors found in this transect include the vegetables being grown, birds, weeds, earthworms, and ants. The vegetables were found growing in the four vegetable beds, and the weeds were found in these beds as well as in the surrounding soil and mulch. Birds were observed flying above the transect and it is presumed they consume the seeds and leaves of the vegetation in the garden. Ants and earthworms were found in the bed of the planters, and ants could likely also have been found in the mulch.

The abiotic, or nonliving, factors observed include the mulch, the planters, the irrigation system, the soil, and the water. Mulch, made of a mix of tan bark and other dead organic matter such as dead leaves and plants, is present throughout this transect, and is on the ground surrounding all the planters. The planters themselves are made of wood, and house all of the vegetation purposefully grown on this transect. The irrigation system is a series of pipes that runs throughout this transect and is responsible for bringing water to the planters. Soil is found in the beds in which the plants are meant to grow, and water is nearly everywhere, including in the soil and in the mulch. The sample collected for the Hay Infusion included soil from each of the four beds in the transect as well as mulch from both around the planters as well near the dead plants towards the back.

Conclusions & Future Directions: Upon closer examination of transect 4 - which had initially appeared to simply be a community garden - it's quite clear that there is an immense amount of life and diversity living and thriving in this environment. The Hay Infusion will further reveal what sort of protists and bacteria have a home in this transect, as well. In order to further understand the diversity of life on campus, it would be interesting to compare this transect of land with the four others, and attempt to comprehend the variance in life present on the American University campus.