User:Eshter Lee/Notebook/Biology 210 at AU
July 14 - LAB 5: INVERTEBRATES AND VERTEBRATES"
Invertebrates are very diverse and is ipmportant in observing a transect. Invetebrates have 14 different phyla. Of the 14, the invertebrates usually found in soil are arthropods. The arthropods are important because they help to break down and decompose waste and they feed on decaying plant material and take fluids from roots (Bentley, 2015).
The invertebrates that have radial symmetry, for example jellyfish, have two embryonic germ layers, ectoderm and endoderm. However, invertebrates with bilateral symmetry allowed three germ layers: ectoderm, endoderm and mesoderm. This is important because it allowed development of inner organ and tissue system.
After the Berlese Funnel was incubated for four days, it was taken down. The liquid was poured into two petri dishes and observed. then e insects visible by eye was observed under the microscope.
In the transect five vertebrates were observed.
Eastern Gray Squirrel House Sparrow European Starling Great Catbird American Robin
Because the transect is identified as temperate forest, many invertebrates are found feeding on decaying plants. The transect has many plant species as identified before and the soil for the hay infusion was found near the plants. The vertebrates found included many bird species. The birds would benefit from trees and the stream of water available to them. It is a good resting place because the temperature is not too hot in the summer due to the shade provided by the abundant trees and the stream. ("The Temperate Deciduous Forest")
The vertebrates found such as American Robin feed on the invertebrates found in the transect, therefore creating a food web.
The vertebrates feed off invertebrates while invertebrates feed off plants and bring nutrients back to the soil. In terms of trophic levels, producers are plants, primary consumers are the invertebrates found and secondary consumers are the bird species found and the Eastern Gray Squirrel.
Having all the three levels of the trophic level creates the community of the transect.
Bently. Biology 210 Laboratory Manuel" 2015.
"The Temperate Deciduous Forest" Marietta College <http://www.mariettacollege.edu/temped.htm>
July 9 - LAB 4: PLANTAE FUNGI
Plants and fungi are diverse and necessary in the ecosystem. Fungi have three major divisions: zygomycota, basidiomycota, ascomycota. Zygomycota's special structure is zygospores in sexual reproduction. Basidiomycota has special structure of basidia under the mushroom in reproduction. Ascomycota has special structure of ascomycetes which are pathogenic.
There are bryophytes and angiosperms that makeup most of the plants. Bryophytes are non-vascular plants such as moss and hornworts. Angiosperms are flowering plants that spread gametes by dispersal.
Most plants have roots for water absorption. However, bryophytes have rhizoids that anchor the plant and help it to spread around the area.
Like so, cell differenciation is apparent in specialization of structures within the plants.
Collecting 5 plants samples from transect
Five plant samples from the transect were taken for observation.
Plant ID application was used to identify each plants and vascularization, specialiation, reproduction system were observed.
Leaf litter were collected from the transect. 25mL of 50:50 ethanol/water solution was in a conical tube. Screeing material was taped to the bottom of the funnel. Leaf litter sample was placed in the funnel and the funnel was taped to the conical tube. The funnel was placed under light and left for four days.
Various plants were taken from the transect and observed. The five plants were identified as fern., ladydogwood, Swamp sawgrass, english ivy and royal standard hosta. Because these plants were near the stream all had vascularization. The plants have different specialized structures because the transect is diverse.
JULY 7 - LAB 3: MICROBIOLOGY AND IDENTIFYING BACTERIA WITH DNA
The objective of Microbiology and Identifying Bacteria with DNA sequences was to understand Domain Bacteria, observe characteristics and its resistance to antibiotic - tetracycline. Domain Bacteria is very diverse therefore, the method of observing the cell morphology is used in identifying microorganisms. Another method is gram staining; bacteria that have peptidoglycan outside of the plasma membrane are gram-positive and show violet/pink color. PCR can be used in observing DNA sequence to identify different types of bacteria.
Four days before, serial dilutions of the hay infusion was prepared and plated. Four tubes were prepared and labeled 10^-2 (tube 1), 10^-4 (tube 2), 10^-6 (tube 3), 10^-8 (tube 4). The first tube had 5mL of broth and 100µL of hay infusion culture was added. Then 50µL was moved from tube 1 to tube 2 and from tube 2 to tube 3 and so on to complete serial dilution. Then eight plates were prepared: 4 with nutrient agar and 4 with nutrient+tetracycline. They were labeled 10^-3, 10^-5, 10^-7, 10^-9. From tube one 100µL were moved to 10^-3 plate and 10^-3 tetracycline plate and 100µL of tube 2 was moved to 10^-5 plate and 10^-5 tetracyline plate and the process repeated for the rest of the tubes and plates. It was then incubated at room temperature for four days.
Then the growth of bacteria was observed. First the bacteria were counted. In order to observed the culture, gram stain was done. From 10^-5 agar, 10^-9 agar, 10^-5 tetracycline, 10^-9 tetracycline plates, small colony of bacteria was taken and put on a slide. Then crystal violet was added, then rinsed off, Gram's Iodine was added, then rinsed off, 95% alcohol was used to rinse gently and safranin stain was used to smear the slide then rinsed off with water. Then the samples were observed under the microscope.
PCR sample was made at the very end. A single colony was added 100µL of water in a tube.
Tetracycline is an antibiotic that is used against microorganisms such as chlamydiae, mycoplasmas, rickettsiae and protozoan parasites. It also exhibits against gram-positive and gram-negative bacteria. Tetracycline blocks part of the stage of protein synthesis by inhibiting aminoacyl-tRNA from attaching to ribosomal site (Chopra). Therefore the prediction is that the plate with 10^-9 nutrient+tetracycline should have the least number of bacteria.
In the experiment, it showed that 10^-3 nutrient agar plate has the most amount of bacteria as it is the one least diluted without tetracycline. However, as table 1 shows, the 10^-9 nutrient + agar plate shows 200*10^9 while 10^-9 nutrient agar plate shows 12*10^9 bacteria. This goes against the prediction that tetracycline slows the growth of bacteria.This could be because the plates were not incubated long enough. Another reason could be that the transect which the Hay Infusion is from can have bacteria that are resistant to antibiotics. According to Chopra, many bacteria which are pathogenic and commensal are resistant to tetracycline.
According to table 1, most of the nutrient+tetracycline plates were not affected by the tetracycline. They showed similar growth to the nutrient agar plates.
Chopra, I., & Roberts, M. (2001). Tetracycline Antibiotics: Mode of Action, Applications, Molecular Biology, and Epidemiology of Bacterial Resistance. Microbiology and Molecular Biology Reviews, 232-260.