User:Libin G. Abdi/Notebook/Biology 210 at AU

Hay Infusion Observations and Serial Dilutions

Purpose: The primary purpose in this lab was to observe and identify living microorganisms found in the particular transect by utilizing a dichotomous key. The organisms were a result from the hay infusion, which can be considered its own ecosystem. Furthermore, these microorganisms play a certain role even within the hay infusion ecosystem.

Materials and Method: Before assessing the hay infusion of the assigned transect, some practice on using a dichotomous key was done. This was to ensure that all parties were clear on how to use a dichotomous key to determine an organism. Afterwards, the hay infusion observations were done. In order to do this, each group was to carefully, without any disturbances, move the culture, and assess its smell and appearance. Then, samples were taken from different areas in the culture and assessed through a microscope. The main intention was to find protists within the culture, using a dichotomous key. Subsequently, serial dilutions were prepared and plated in order to closely examine the bacteria in the hay infusion. This was done by taking broth and putting it into 4 test tubes labeled 10^-2, 10^-4, 10^-6, and 10^-8. Then 100 microliters of culture was taken and put into the first tube labeled 10^-2, and from that test tube 100 microliters of solution was taken and out into the test tube labeled 10^-4., so on and so forth. Once this was done, 100 microliters of the solution in test tube 10^-2 was plated on the agar plates labeled 10^-3, so on and so forth. One set of plates were nutrient agar and the other set was nutrient agar and tetracycline.Diagram below:

Data and Observations: In transect four, the hay infusion made was brown in color yet relatively clear in that you could easily see the bottom of the jar. The odor is best described as musty and no apparent signs of life could be seen. The samples taken were from two different areas: very bottom of the jar and the top. On the bottom of the jar, we were able to find various protists inhabiting the culture including arcella (63 micrometer in length), paranema (45 micrometer in length), and paramecium (35 micrometers in length). All were motile, easily shown as they had mechanisms such as cilia or flagella that made them mobile. None were photosynthetic, as they were colorless and had no chlorophyll (no green pigmentation present). In the top sample, different organisms were found including colpidium (51 micrometers in length), chilomanas (22 micrometers in lenght), and lastly paramecium aurelia (which was the largest at 156 micrometers in length). All of these were protozoa and non were photosynthetic. They were all motile, demonstrating mechanisms that made them so (presence of cilia or flagella).

Conclusions and Further Directions: This lab depicted how diverse an ecosystem can be although it may not seem promising just by looking at it. Also, organisms occupy different niches in ecosystems, regardless of the size of the ecosystem. Moreover, due to the location, certain organisms will live in certain places while other do not. This was the case with transect four's hay infusion as different organisms were found in different locations. All of the organisms inspected has been protists. One of these was the paramecium aurelia. The paramecium aurelia meets all the needs of life. If the hay infusion culture was to "grow", I would expect for there to be more organisms present as the protists present now would have had time to reproduce. Additionally, I would think that organisms would change due to selective pressures placed on them. For example, if perhaps those organisms living near the leaves needed those leaves to survive, they could very well eventually die out as the leave begin to decay.

01/29/15

Primary Observations for Transect 4

Purpose:This is a current and progressing experiment that allows students to observe a particular ecosystem within American University. From these ecosystems, students will gradually learn the importance of different organisms (such as animals, plants, and bacteria) and their niches in an ecosystem. The main purpose of this lab is to demonstrate the relevance of diversity within an ecosystem.

Materials and Methods: Each group was assigned a specific 20 X 20 transect, a section of land meant to represent an ecosystem. In this group, transect 4 was assigned. The group was to carefully observe and record aspects of the transect, including but not limited to: biotic and abiotic features, animals, plants, etc. Variables that could affect later observations in the transect include human activity. Because this particular transect was the university's community garden, it would be open to human disturbance. Temperature/weather is also an important variable as the transect is being observed during colder temperatures (i.e. wintertime). The initial observation was followed by a hay infusion, which allowed students to take a 50 mL sample of soil and ground vegetation that would fully represent the entirety of the transect.

Data and Observations:Transect 4 is located near the back end of the university and is fenced completely around making it comparatively isolated. Nevertheless, due to this transect being the university garden, it is no stranger to human disruption. The transect is well kept and has various different vegetables growing such as broccoli, kale, corn and cucumber. Each crop is separated according to type and have been put in boxes. These plants were well watered through a watering system that had been set up. Certain plants had shown more growth while others had either little to no growth.

The abiotic (non-living) features of the transect include hay, mulch, soil, rocks and water (from the irrigation system). The hay, mulch and rocks were present nearly everywhere except for the plant beds, while rocks, soil and water were more apparent in the plant beds. The biotic (living) factors included vegetables, birds, squirrels, earthworms, and grass. The vegetables were clearly in their planting beds. Animals, such as the birds and squirrels made some frequent appearances on the transect, while others like the earthworms stayed within the soil. Grass, like the hay and mulch of the abiotic factors, was mainly on the ground, separate from the plant boxes. For the hay infusion, soil from each plant bed as well as the ground were taken as was grass, hay and mulch. This ensured that the hay infusion would be a good representation of the entire transect.

Conclusions and Future Directions:The fourth transect will continue to be monitored by the group members. It is clear that a glance at this transect would not suffice to show how diverse the life present is. Only careful and precise observations would show that. Later on, the hay infusion should be able to reveal more about the life present on this transect.

01/26/15

First Post

Hi, This is Libin :)

01/22/15