User:Jamie Nunziata/Notebook/Biology 210 at AU

Observing and Identifying Protists in a Hay Infusion Culture

01/28/2015 J.N.

Introduction:
This lab was performed to observe and identify various protists that may be living in our transects. Protists are unicellular eukaryotes that do not perform photosynthesis but instead absorb their own nutrients. These protists can also have many different unique characteristics passed on by their particular lineage. These unique characteristics are crucial observations when it comes to identification. One method of organism identification is by using a what is called a Dichotomous Key. Dichotomous Keys offer choices on the physical characteristics that may be present in your organisms, such as the organism's shape or color. Those choices may lead you to other choices about your observations, and by the end of it you would have narrowed it down to the species you are observing. This lab used a dichotomous key in order to identify the protists we saw in our wet mount of our Hay Infusion culture. To observe an bacteria that may have been present in our culture, agar plates were prepared for observation in our next lab. The purpose of this experiment was to develop techniques for identifying organisms by using a Dichotomous Key and to observe the different protists that may be present in our transect.

Materials and Methods:
To prepare the Hay Infusion culture, our dirt sample collected from our transect was put into a large jar. 500 mLs of distilled waterand 0.1 gram of dried milk was added to the jar with our sample. The mixture was shaken for about 10 seconds and placed into the back of the class, top off, for observation after 1 week of leaving the jar undisturbed. After that week passed, the jar was then collected again and observations were made of the undisturbed environment. Then, the Hay Infusion culture was shaken until it became a homogenous mixture again. Samples were drawn from the culture using a transfer pipette from the top and bottom of the culture and placed on wet mount slides for observation.

In preparation for next lab, we prepared an plated a serial dilution for bacteria plating. To due this, 4 tubes of brother were obtained and labeled 10^-2, 10^-4, 10^-6, or 10^-8. Using a micropippetor, transfer 100 microliters of your hay infusion culture to the tube labeled 10^-2. The tube was shaken to mix the broth, and 100 microliters was then transferred from the 10^-2 broth to the broth labeled 10^-4 and shaken. 100 Microliters was then taken from that brtoh and transferred to 10^-6, shaken, and then broth was taken from the 10^-6 tube to the 10^-8. This final tube, 10^-8, is a 1:100000000 dilution. This process is illustrated below:

Observing a Niche at AU

01/26/2015 J.N.

Introduction:
This lab was performed to serve an introduction to ecology, the branch of biology that studies the different relationships between organisms, species, and the environment (Bentley et al., 2015). In this lab, a transect, or a small section of an ecosystem, was observed to identify any biotic and abiotic factors. Biotic factors are living things, such as moss, and abiotic factors are nonliving things, such as a stop sign. Samples of dirt the various transects were also taken to perform a Hay Infusion Culture that will be observed in the following lab. The purpose of this experiment was to gain a better understanding of the abiotic and biotic factors of different ecosystem by observing specific and unique transects across American University's campus.

Materials and Methods:
The class was first split into groups and assigned different 20 by 20 meter areas of campus to use as their transect. Once each group got their assignment, they went to their assigned area and received a tube from the instructor to take dirt samples from their transect to perform a Hay Infusion Culture in their next lab. The groups then comprised a list of abiotic and biotic factors in their transect along with recording the transect's overall location and topography. Each group member then, independently, sketched their transect to include an overall biological setup of biotic and abiotic factors, along with a having labelled north, south, east and west.

Data:
The transect that was used for this analysis was the Tall Bushes Transect and was located in the middle of an arboretum in between the amphitheater and bender arena. This transect included lamp posts, dirt, and sidewalk cement as its abiotic factors. As far as the biotic factors, this transect contained many different types of ground shrubs and bushes, some small trees, grass, small bugs and microorganisms in the dirt, and some fallen leaves. The overall topography of the transect was that it was flat and higher up in altitude than it's surroundings, and the transect was fairly dry when digging past the top layer of snow. A sketch of the transect can be seen below:

Conclusion:
This lab was aimed toward making observations about a specific ecosystem by analyzing a small sample, or transect, of that ecosystem. The results of this experiment were that most of the biotic factors in our transect were small trees and bushes on the ground, which is an outcome of the fact that our transect was in a dry and high up location. This location was also in an area where their is no immediate water source, also contributing to the observation that the only plants able to sustain life in our transect were ones which could survive in dry areas.

References:
Bentley, M., Laslo, M., Walters-Conte, K., & Zeller, N. (2015). Aerobic Respiration & Fermentation. In A Laboratory Manual to Accompany General Biology 2 (pp. 16-17). Department of Biology, American University.