User:Corina C. Velazco/Notebook/Biology 210 at AU

Identifying Algae and Protist: Lab 2 on January 28, 2015

Purpose: To understand how unknown organisms are identified, the dichotomous key is used after making observations about size, shape, motility and color. This is used to understand the different characteristics of unicellular eukaryotes-- protist and algae. Protist and Algae will be identified In the Hay Infusion Culture from the transect #2 that was made last week.

Materials and Methods: In order to get familiarized with how the dichotomous key works, first a wet mount of known organisms are observed under the microscope and the dichotomous key is used to identify it in order to make sure that it can be used with unknown organisms now. After successful identifying at least two known organisms, Hay Infusion Culture observations can begin, but first the culture must be observed without disturbing it. Secondly, two samples must be taken for observation from two different niches (in this case, top and bottom). A wet mount is made for each of the samples and protist and algae from the Hay Infusion Culture are identified. Finally, to prepare for Lab 3, a total of eight petri dishes will be prepared. Four of those will contain agar+tetracycline and the other four will just contain agar.

Data and Observations: After one week, the Hay Infusion Culture had a strong foul odor and water had already started to evaporate. The water was significantly muggy and the berries and a wood chip were on the top along with a layer of slime. The moss and the soil were in the bottom of the jar. The two samples of the different niches were taken from the top and the bottom of the culture. In the wet mount of the sample taken from the top, colpidium and gonium were identified. Gonium was 20µm, green color, with many disc shaped cells. Colpidium which was also found in the wet mount of the sample taken from the bottom measured 25µm. This organism was oval-shaped and colorless and exhibited motility since it was entirely covered in cilia. If the Hay Infusion "grew" for another two months, it will slowly begin to evaporate and the organisms will begin to reproduce, however the fact that the liquid is evaporating may deter the organisms from living in the jar. In addition, organisms might not be able to continue to live in their niche because there is a limited amount of nutrient supply.

Conclusions and Future Observations: From observing the Hay Infusion Culture, clearly there are many organisms living in the different niches. In this case, protist and algae were identified, however, these unicellular eukaryotes are not the only organisms that may be present in the Hay Infusion Culture. Next week, we will be looking for bacteria in the petri dishes created after this lab.

Biological Life at AU: Lab 1 on January 15, 2015

Purpose: To observe evolution through natural selection, an ecosystem, also known as a transect, at American University will be observed and analyzed. The biotic and abiotic components will be observed and then a sample from the assigned transect will be taken to examine it through the first several weeks of the semester. This is done to study the interactions that occur in a specific niche and see all the different species that live there.

Materials and Methods: First, the TA gave each student a number to have groups of three assigned to each transect. Once given the map, my group went to the transect and observed, analyzed and took the sample with a 50mL conical tube-- 50% of the soil from the transect and the other 50% consisted of moss, grass, berries and leaves. Then back in the lab a Hay Infusion Culture was made by mixing 10 grams of the sample gathered from the transect with 500mLs of deerpark water (that way there were no pollutants), and 0.1 grams of fried milk. This mixture was covered with a lid and mixed for 10 seconds and then the jar was placed in the back of the lab without the lid.

Data and Observations: The 20 by 20 meter transect that was assigned is located on the North side of campus on the side where Hughes Hall and McDowell Hall are adjacent to each other (labeled #2). Its biotic components consisted of trees, moss, bushes, grass and berries. Its abiotic, or nonliving, components consisted of rocks, occasional shade from the Hughes Hall building, benches, soil and snow.

Conclusions and Future Directions: The biotic and abiotic components in the transect affect the population living in it. By observing the niche, will help identify and learn about the species in that specific niche. The Hay Infusion Culture will be observed the following week and different species will be observed. This provides an idea of how an ecosystem provides a habitat to a diverse amount of species and also it further helps us understand the many life forms caused by evolution.

CV

1.27.15 Good first entry. Nice structure and layout. Good pictures. SK