User:Alexandra A. Taylor/Notebook/Biology 210 at AU

January 21, 2015
In this lab we identified different strains of algae and protists, first from slides and then from our hay infusion. When we brought the hay infusion over to our work area, we could immediately smell a very strong organic odor. The water was cloudy, and had a thick, silvery skin formed on top of it. We did not notice anything else, such as mold, growing over the top.

We obtained samples from two different locations within the jar and made wet mounts to examine under the microscope. The first sample came from the top of the water, just below the skin and beneath a twig that was sticking out of the water. Judging by the wet mount, this area seemed to be the less populated of the two. The first organism that we observed was a ovular, with circular green spots in the middle. It seemed to be somewhat bent, and was constantly spinning. Matt mentioned the possibility that the organism's flagella could be folded over itself and thus not visible. Based on most of its characteristics, it seems likely that this may have been a paramecium, although the fact that it appeared to contain chloroplasts would seem to counter this.

The next organism that we looked at appeared as a cluster of about 16 green spheres, probably colonies of smaller organisms, arranged in a single plane. This organism also appeared to be photosynthetic and was non-motile. Based on its appearance, I would guess that this was a Gonium, but it may also have been a Pandorina.

The second wet mount sample we took from the bottom, and this contained many more life forms. Brown algae was a big part of this environment. I would speculate that the brown algae provide protection as well as a food source for heterotrophic organisms, which may be why they are more attracted to the bottom of the infusion than the top. The first organism that caught our attention was moving very quickly and thus difficult to hold in the field of view for very long. It was shaped like an oval with a crescent-shaped indentation on one side. The water was moving very rapidly around it, which points to its having cilia even though they were not immediately visible. Because of its rapid motion, I would categorize this organism as a scavenger and thus a heterotroph. Based on these characteristics, it seemed to resemble a blepharisma.

As previously mentioned, brown algae made up a large part of the second wet mount. The average algae was a brown, furry-looking clump about 175 um in length and non-motile. Additionally, there were many round, green, oval-shaped organisms floating around in the water, about 2.5 um in length. These we classified as Chlamydomonas, as they shared all of the same characteristics of the organisms we had examined the previous week. Finally, we also discovered a Volvox, which was large (137.5 um), round, and green, largely transparent with tiny dots and three larger, darker round areas throughout.



The Volvox fits the five qualifications of life by...
Reproduction: reproduces oogamously, contains specialized reproductive cells (female gamete larger than the male)
Evolution: most complex in the Volvocine line, evolved from the simplest form Chlamydomonas and intermediate form Gonium
Information: each of the thousands of cells in the colony contain genetic information that direct their development as well as reproduction
Cells: composed of a colony of thousands of spiked cells displaying simple specialization (vegetative vs. reproductive)
Energy: cells contain chloroplasts which allow them to convert light energy into chemical energy via photosynthesis

If the hay infusion culture were to grow for another two more months, I would expect to see the algae population thrive and become more present in other areas of the jar. The algae seemed quite hardy and also seemed to have grown the most quickly based on size of any of the other photosynthetic organisms. I might expect this to mean competition for the other photosynthetic organisms, because the algae might eventually block out the light available due to its dark color. The increased presence of algae would also provide additional food for the heterotrophic organisms, which I expect would thrive in this environment.

After examining our two wet mounts under the microscope, we performed a serial dilution of the culture in growth medium, and then transferred 100 ul from each tube onto nutrient agar plates. The serial dilution process is detailed below.



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January 14, 2015
Today in lab we examined the concept of evolution, using three members of the Volvocine line as an example. Organisms in the Volvocine line belong to the green algae group, Chlorophyta. The three organisms that we viewed, ranging from least to most complex, were Chlamydomonas, Gonium, and Volvox. The chart below details observations collected on each genus.


We were assigned the wildlife habitat transect. The area is located on the northern part of campus next to the Hughes building. It is located on sloped ground and has several benches and flagstones for foot traffic. We photographed the transect, made note of biotic and abiotic elements inhabiting it, and then collected a sample of soil and surface matter to be use in a hay infusion. We took this back to the lab, added it to a jar with some distilled water and powdered milk, and left it sitting open on the counter.

Biotic elements: trees (3 varieties), grasses (3 varieties), mulch, moss, berries. Below is a map of the transect, as well as some photographs.
Abiotic elements: snow, flagstones, rocks, signs (2).






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