User:Sithara Thalluri/Notebook/Biology 210 at AU

1/28/15

Lab 2: Identifying Algae and Protists

Purpose: The purpose of this lab was to practice using a dichotomous key while observing our hay infusion cultures. Also in this lab we learned how to prepare and plate serial dilutions.

Materials and Methods: Procedure 1: In the first part of lab we observed pre-plated organisms and and attempted to sort them according to the dichotomous key. We also made wet mounts of known organism and then observed them. We made these observations under a 4X then 10X.

Procedure 2: In this part of the lab we examined our hay infusions from last week's lab. Once obtained, we noted the appearance and smell of our hay infusions (made with components of our assigned transects). We then extracted two different samples from our hay infusions - each representing a different layer or niche of our jar - and then prepared two wet mounts with each sample. Then, using the dichotomous key, we found three different organisms in each of our two 'habitats' from the top and bottom of the culture.

Procedure 3: In the last part of lab we did a serial dilution with 10mLs of sterile broth and samples of our hay infusions. In the dilution, we labeled four test tubes containing 10mLs of sterile broth with 10^-2, 10^-4, 10^-6, and 10^-8. We then obtained four agar plates, and four agar plates with tetracycline - and labeled those respectively as containing tetracycline or not, while also labeling them 10^-3, 10^-5, 10^-7, and 10^-9. We then added 100µl of our hay infusion culture to the 10mL of sterile broth labeled 10^-2. Then we added 100µl of the swirled tube labeled 10^-2 to the tube labeled 10^-4, and repeated the steps on the remaining two tubes. Then we needed to plate our dilutions. To do so we we used a pipette, spreading rod, alcohol bath, and an open flame (the last two items were used for sterilization performed after every plating of the spreading rod). We used the pipette to add 100µl from the 10^-2 tube to the agar plates (with tetracycline and w/o) labeled 10^-3 - and we repeated this step with each increasing number. Then we carefully wrapped the plated in aluminum foil and let them sit on a rack.

Data and Observations: When we brought back our hay infusion we noted that it had no noticeable scent. It was a brown and green murky color and had tan clusters of film present on the top. We obtained three organisms from the top, chilomonas (22um), colpidium(51 um), and paramecium aurelia (156um). All three of these organisms were motile, and protozoa - thus making them non-photosynthetic.

These images are of the organisms respectively : File:IMG 0891.jpeg File:IMG 0890.jpeg

From the bottom sample of our hay infusion we found peranema (45 um), arcella (63um), and paramecium bursaria (156um). These organism were also all motile, non-photosynthesizing protozoa.

These are images of the organisms respectively: File:IMG 5072.jpeg

Conclusions and Future Directions: This weeks lab really emphasized the scale of organisms, and illustrated the wide spectrum of life present just on our own campus. For instance, and organism such a paramecium meets all the needs of life: energy, cells, replication, information, and evolution.

1.27.15 Good first entry. Need to include more detail for example there is no mention of the Hay Infusion set-up. Pictures would add information. The transect was 20Ft by 20Ft, not meters, there is a typo in the manual. SK

1/26/15

Lab 1: Biological Life at AU

Purpose: The purpose of this lab is to observe and analyze the ecological interactions occurring in our given “niches” represented by a 20 x 20 meter transect of land somewhere on campus. We will explore the sheer amount of biological diversity present just within American University’s campus alone through weekly visits to our given niches.

Materials and Methods: Each group was assigned a transect of land that is 20 x 20 meters large and we are responsible for observing and analyzing the ecology of the environment and recording data. The transect of land is the AU student run community garden behind Leonard Hall next to the campus tennis courts. We are responsible for weekly observations of our plot and data recording.

Data and Observations: We observed the agricultural nature of the transect which included an irrigation system(hoses running through each separate garden box), presumably fertilized soil(only in the garden boxes), and of courseseparate wooden garden boxes for each different plant. The plants present in our transect of the garden are brussel sprouts, lettuce, kale, and cucumbers. In addition to the more uniformed boxes, there is an area of stray leaves, mulch, and hay on the edge of our transect.

Biotic features of our transect included things such as: pests, rodents, birds, weeds, vegetables, earthworms, etc. While abiotic features included: air, water, soil, mulch, etc. One prominent factor that will determine the state of our transect is human interaction because it is a garden that depends on irrigation and human maintenance.

Conclusions and Future Directions: I think it will be interesting to observe the qualities in our transect in contrast to the more naturally occurring transects that students have - as our transect is so influenced by humans. I also am interested to see the interactions between the vegetables and the attraction of pests to the garden.

1/22/15 Test