User:Meghan E. Caul/Notebook/Biology 210 at AU

Lab Notebook Entry: Week #1

Meghan Caul 20 January 2015 BIO-210-005-2016S

On January 13, 2016, my group and I (group #3) observed a 20x20 transect located in between the outdoor amphitheater and Hughes Hall on American University's campus. Our assigned ecosystem is on a slightly tilted landscape and contains a man-made stream, a stepping stone pathway that continues through the stream, scattered deciduous trees, and a diversity of shrubs and other dwarf vegetation. Biotic components include: black squirrels running up the deciduous trees, brown birds (resembling finches) perched upon the branches of the deciduous trees, dwarf fern shrubs of a vibrant green color nestled into the topsoil, green wild onions sprouting from the topsoil adjacent to the stream, and green/black (mixed color) fungus located closer to the side of Hughes Hall. Abiotic components include: smooth gray and brown stones of various sizes tucked into both the centrality and meandering edges of the stream, stream water flowing in a downhill direction (due to tilted landscape), damp soil, or mud, on land adjacent to all edges of the stream, larger sized boulders (resembling granite) with rough texture make up stepping path, and fallen limb/bark/leaf pieces that scatter the entirety of the transect (due to Winter season).

Pictures of transect and its components:

M.E.C. 20/01/16

Lab Notebook Entry: Week #2

Meghan E. Caul 3 February 2016 BIO-210-005-2016S

Upon revisiting our group's (Group #2) Hay infusion culture on January 20,2016, a change in odor immediately presented itself. This worsening was most likely caused by bacterial proliferation that occurred in the week the culture was without contact. There was also a thick (1 cm) layer of sludgy mold floating atop the surface. It, along with the rest of the culture, also developed a darker pigmentation (opaque dark brown/black). We predicted the presence of Archaea in our agar plates to be unlikely because of our transect's lack of extreme temperature and soil salinity. However, If any were to be present they would most likely be identified as mesophiles due to the pollution within our transect. We later discovered a complete absence of Archaea. After preparing a total of 5 wet mounts containing a protozoa survey mixture (3 extracted from bottom of Hay Infusion jar and 2 from top--difference of one due a classroom cover-slip outage) and focusing under a 40x lens microscope, my group and I struggled to identify specimens due our culture being mostly devoid of life. We were, however, able to examine and identify many of the same species. This species, seeming to be the only kind in our Hay infusion, most closely resembled either Amoeba or ciliates and were intermittently motile. Additionally, we observed a bigger form that possessed an inner green ring but were unable to determine whether it was biotic or abiotic.

Agar plates treated with varying concentrations of tetracycline showed significantly more bacterial colonization and fungus that those within the control group (absence of tetracycline). These visible colonies appeared orange and blue in color and were most profuse within tet 10^-3 and tet 10^-5 agar plates (thousands of colonies) than in tet 10^-7 and tet 10^-9 agar plates ( a few dozen colonies). The agar plates lacking tetracycline treatment had minimal bacterial colonization and some translucent, fuzzy fungus.This data indicates bacteria present within the agar plates either are insensitive to the antibiotic used (tetracycline) or are antibiotic-resistant. Research demonstrates there are three mechanisms by which bacteria develop antibiotic resistance. These include tetracycline reflux, ribosome protection and tetracycline modification. It is important to also note that these mechanisms provide an increase in bacterial reproductive fitness and have been observed in both gram-positive and gram-negative bacteria. This further supports the claim that being antibiotic-resistant in an environment that allows for antibiotic exposure is beneficial to one's reproductive fitness. Diversely, tetracycline remains effective against specific intracellular bacterial pathogens (ex. Chlamydia).

Sources Cited: Antibiotic Resistance. (n.d.). Retrieved from http://www.antibioresistance.be/tetracycline/menu_tet.htmlSpectrum of Bacterial Susceptibility (n.d.). Retrieved February 01, 2016, from https://en.wikipedia.org/wiki/Tetracycline#Spectrum_of_bacterial_susceptibility

Pictures of examined specimens:

M.E.C. 03/02/16

Lab Notebook Entry: Week #3 Meghan E. Caul 10 February 2016 BIO-210-005-2016S

The genus of plant #1 (fern) is Equisetum. The genus of plant #2 (silverweed) is Potentilla. The genus of plant #3 ('Cherry Cheeks' Daylily) is Hemerocallis. The genus of plant #4 (maroon perennial) is Geranium. The genus of plant #5 (brown seed/legume) is unknown. Fungal sporangia is a spherical, black-ish structure comprised of several hyphae filaments. When open, spores--carrying genetic material--flood out and disperse into the environment. When analyzing a sample on an agar plate with a microscope, I looked for the presence of hyphae. Upon seeing many of this filaments and strands of conidia (appearing to be chains of connected raindrops), I identified the sample as containing multicellular fungi. Please refer to the chart below for details regarding plant sample characterizations. Also included is an image of each of the five examined samples from transect #2.

M.E.C. 10/02/16

Lab Notebook Entry: Week #4

Meghan E. Caul

10 February 2016

BIO-210-005-2016S

Analyzing Invertebrates

The first step in setting up a Berlese funnel was to pour 25 mL of 50:50 ethanol/water solution into a 50 mL conical tube. Next, a fragment of lattice-designed screen was positioned at the bottom of the funnel. The leaf litter sample (from transect #2) was then placed in the top of the funnel. The next step was to secure the funnel to a ring stand and parafilm the base of the funnel. Lastly, the funnel was wrapped/covered in tin foil and stored in a light-controlled environment. Sample (petri dish)#1 was assigned in reference to the upper half whereas sample (petri dish) #2 was assigned in reference to the bottom half of the Berlese funnel collection. Sample #1 contained approximately a dozen termites varying in size (smallest: 3.5 mm in length; largest: 9 mm in length. Sample #2 contained a few termites, a flea, and a pseudoscorpion/spider. The overall size range of both samples ranged from 2 mm to 9 mm (mean size [in length]: 5 mm), with the longest specimen being a termite identified within sample #1 and smallest specimen being a pseudoscorpion/spider identified within sample #2. The most common identified species was the termite due to it being present within both samples. Sample #2 contained three different species (termite, flea and pseudoscorpion) whereas sample #1 only harbored a single species (termite). Please refer to the chart for details regarding characteristics of species examined. Also attached is a photo of termites identified in Sample #1 and a sketch illustrating digestive differences in protostomes (in which the mouth develops faster than the anus) and deuterostomes (in which the anus develops faster than the mouth).

Vertebrates and Niches

Five vertebrates that may inhabit my transect include: Brown finch (Phylum: Chordata, Class: Aves, Order: Passeriformes, Family: Fringilidae, Genus: Haemorhous, Species: H. mexicanus), American toad (Phylum: Chordata, Class: Amphibia, Order: Anura, Family: Bufonidae, Genus: Anaxyrus, Species: A. americanas), American crow (Phylum: Chordata, Class: Aves, Order: Passeriformes, Family: Corvidae, Genus: Corvus, Species: C. brachyrhynchos), chipmunk (Phylum: Chordata, Class: Mammalia, Order: Rodentia, Family: Sciuridae, Genus: Tamias) and a rat snake (Phylum: Chordata, Class: Reptilia, Order: Squamata, Family: Colubridae, Genus: various). Because all of these are woodland creatures, they all need access to food (proper nutrients), a water source, and shelter (foliage). Our transect (#2) contains all of these requirements (i.e. insects, berries, small mammals, birds, snakes, running stream, shrubs, trees, wild grasses/weeds and flowers, arid soil, various stones, etc.). This collection of species interacting and abiding within the same habitat can be considered a community. Considering the small size of our transect--the habitat under study--the observed biodiversity all share similar survival requirements. If the parameters under study were expanded, the carrying capacity would increase in response due to added availability of more and different territory/niches. Please refer to the food web diagram below for details regarding the species' trophic levels.

M.E.C. 10/02/16