User:Ricardo M. Rodriguez/Notebook/Biology 210 at AU
January 26, 2015 Identifying Algae and Protists
The purpose of this lab is to practice using a dichotomous key to identify unknowns, understand the characteristics of Algae and Protists, as well as examine them from our transect. It is important to have this set of skills because it’ll help us to further understand our ecosystem. Hypothesis: Because we have such a diverse amount of soil and vegetation in our 500mL beaker, we will find a lot of different bacteria.
Materials and Methods The materials used for this lab were:
Light microscope, dichotomous key, known organism, Hay Infusion Culture, micropippetor, four nutrient agar plates, and four nutrient agar plus tetracycline plates.
Method 1: We make a wet mount of known organisms and observe them under a microscope and measure its size.
Method 2: Afterwards, we get a hold of the dichotomous key and try to identify the organism using the information we collected from the microscope.
Hay Infusion Culture Observation
Method 1: With our culture in front of us, we note the smell of our sample (putrid smell) and described its appearance.
Method 2: We take samples from two different niche as well as including plant matter in our observation. We make a wet mount from the two different niches and determine what protists and algae are present with the help of our dichotomous key and draw pictures.
Preparing and Plating Serial Dilutions
Method 1: Label four tubes of 10 mL sterile broth with 10^-2, 10^-4, 10^-6, and 10^-8. Set a micropippetor to 100 microliters. Obtain four of each kind of agar plate--label all of the tetracycline plates with "tet." Label each of plate with their respective numbers, and add your lab group's info on the plate. Swirl the Hay Infusion Culture--with the lid on-- to mix up the contents.
Method 2: Add 100 microliters from the culture to the tube labeled 10^-2. Mix the tube thoroughly. Add 100 microliters of broth from this tube to the 10^-4 tube and swirl to mix well. Repeat this twice to make the 10^-6 and 10^-8 test tubes. Pipette 100 microliters from each tube onto their respective nutrient agar plate (10^-2 goes on the plate labeled 10^-3, etc.), and spread it around the plate carefully.
Method 3: Repeat this procedure for each nutrient agar plus tetracycline plate. We then place the agar plates in a safe spot in the lab where they will incubate at room temperature. Image:Serialdilution.jpg
As told in the procedure, the smell coming off of our culture was putrid. It smelled like spoiled veggies and cheese. With the life forming on top of it, brown and gooey, with a thin skin on top and soil resting on the bottom. There was a skin-like structure on the top of the liquid with vain like appearance. As you can see from the image below, there are some apparent life growing on top of the liquid such as mold and green shoots.
Image:Screen Shot 2015-01-29 at 12.34.29 PM.png
Here is a more detailed drawing of our observation: Image:Hayinfusion.jpg
Sample 1: Image:Sample3.jpg From our observations, we noticed that this sample contained a non-motile species that we had trouble identifying with the dichotomous key. It had some green parts, leading us to believe it was a species that performed photosynthesis. Its size was 50 micrometers.
Sample 2: Image:Sample2.jpg This sample contained a diverse amount of organisms including colpidium, at least two different types of paramecia, and an organism we suspected to be some kind of worm (very long with worm like structures and a moving tail). The colpidium were about 50 micrometers in size, and the paramecia ranged from 70-100 micrometers in size.
Sample 3: Image:Sample1.jpg Just like sample 2, this sample contained more colpidium and various paramecia.
My hypothesis was correct to a certain point. All though we did find a variety of organisms within our sample, we only found 3 out of the 20 on the dichotomous key. This maybe a result from the limited resources we had to pick out a sample from. Maybe if we chose different samples from different areas on campus, we would have gotten a wider variety of organisms. Aside from that, the protists found in the hay infusion culture were both heterotrophs and autotrophs. It was very hard to determine the name of some of the organisms we observed. This could be solved by having a dichotomous key that would be more precise. The one we had was very broad and a lot of the descriptions on it could have been applied to many other organisms.
