User:Student 62/Notebook/Biology 210 at AU
February 15, 2016- Exercise V: Vertebrates and Invertebrates
The purpose of this lab was to use a dichotomous key to identify invertibrates from our transect, describe the differences in their mechanisms of motility, to define and give examples of acoelomates, pseudocoelomates and coelomates, to recognize various types of symmetry and to understand the differences in digestive systems between flatworms, roundworms, and annelids.
Methods and Materials
Procedure I/II/III- First we observed the sample organisms from the five major classes: Arachnida, diplopoda, chilopoda, insect, and crustacea and determined which organism matched which identity based on the dichotomous key. We then moved on to our leaf sample from last weeks lab, taking the Berlese Funnel and gently pouring 15mL of 50% Alcohol and organisms into a pitri dish and placing the left overs into a second pitri dish. We placed these dishes under a dissecting microscope and searched for tiny invertebrates. Our groups dishes did not have any, so we borrowed some solution from another group. We found only 5 organisms (some of which appeared to be the same species) and recorded our observations of them in a table.
Conclusion: Each of these organisms are so tiny that they can only be seen clearly with a microscope. The ones we found ranged from 1.5mm to 3mm. We found two arthropods, two molluska and one platyhelmenthe. The most common types of organisms in a leaf litter are mites, tics, worms, centipedes, millipedes, ants, beetles, and spiders. We only found organisms that resembled an ant like creature, a worm and a mite. Both of our samples contained few organisms.
Procedure IV: In our transect, vertebrates include robins (Chordota Aves Passeriformes Turdus migratorius), squirrels (Chordata mamalia rodentia sciuridae Sciurus carolinensis Gmelin, rabbits (Chordata mamalia lagomorpha Oryctolagus cuniculus, and gold finches (Chordata Aves Passeriformes Fringilidae Cardeulis tristis. The soil would be good for the birds because it would host worms for them to eat. There would also be many seeds from which they could feed. The rabbits could eat the vegetables and grasses within the garden and could dig holes in the soft earth or use the woodchips/ boxes to hide or use as camoflauge. The squirrels could also benefit from this, being able to easily find places to bury their nuts.
Each of these organisms plays an important role in the food web, from the most dominant predator to the decomposers, each organism relies on every single other organism in the ecosystem for its source of food. They all live in a community that indirectly and directly effects growth and survival rates. Decomposers may be the most important part of this ecosystem because they are what breaks down dead organic matter to clear space and provide nutrients for plants and thus animals. Each level in the web is important to the community carrying capacity because it regulates how species grow and die and how they keep the other species from growing out of control.
February 11, 2016- Exercise IV: Identifying and studying Plants and Fungi
Purpose: The purpose of this experiment was to give examples of how plants evolved, describe the characteristics of fungi and be able to recognize it’s difference from a plant, to know the difference between angiosperms and bryophytes and provide examples of each, to understand the alternation of generations in bryophytes or angiosperms and finally, to identify the structure and function of plant reproductive organs.
Methods and Materials: We returned to our transect to collect a 500g sample leaf litter containing dead leaves, soil and plant matter and placed it in a ziplock bag. We also took samples from five different plants and looked for seeds or flowering plants which we were unable to locate (most likely due to the cold weather). We were unable to find any seeds in our transect because none of the plants in the garden are flowering plants. After recording our observations from the five leaf samples we took, we observed bread mold in a petri dish, better known as Rizopus stolonifera. This is a type of zygomycete that grows on fruit, bread and other foods, forming a whitish mass of hyphae filaments called mycelium. This particular mold was growing from a corn plant. On top of the hyphae were black globelike structures called sporangia which contain spores. Following this observation, we then used prepared Berlese funnel in order to extract any organisms from our leaf litter. We poured 25 mL of ethanol/water solution into a conical tube. We then fit a piece of screening material into the bottom of the funnel and taped it in place. The leaf litter sample was carefully stuffed into the top of the funnel with the bottom taped to the inside of the tube so that the mouth of the funnel was submerged in the ethanol. The structure was clamped in place with a ring stand and placed under a 40 watt lamp, about 1-2 inches from the top of the litter, and covered with foil. It was to be left until the next lab period.
Data and conclusions: Transect sample plants Location and # in transect Description (size and shape) Vascularization Specialized structures Mechanisms of Reproduciton 1 ground plant Ovular, 18 cm leaf Netlike veins Stomata seeds 2 Ground plant 32 cm, linear Parallel veins Stomata seeds 3 Ground plant 7cm ovular Web-like veins Stomata seeds 4 Ground plant 4.5cm, ovular Netlike veins Stomata seeds 5 Ground plant 14cm, spade Netlike veins Stomata seeds
This is a picture of the Rizopus stolonifera.
It was unfortunate that we were not able to acquire any seeds, but we knew that these plants reproduced through seeds because of our background knowledge of plants. It was interesting to learn about the various ways in which plants spread and reproduce as well as how their structure is often related to their function. When we tried to determine if the leaves were moncot or dicot, we came to an agreement that they were all dicot except for plant number 2 because of its parallel veins. If we were to do this experiment again, it would help to wait for the weather to turn warm so we could view the plants in their full form. LB 2/11/16
January 28,2016- Exercise III: Microbiology and Bacteria
Purpose The Purpose of this experiment was count and observe the bacteria from our Hay Infusion Culture and take note of their morphological diversity and characteristics. We also tested for naturally occurring antibiotic resistance while identifying these bacteria based on their morphology, motility, shape, and gram stain. We used PCR to verify our assessments.
Materials and Methods Before we began our bacteria identification processes, we made one last observation of our HIC. The top film was gone, and the bottom had a more solid, sooty look, that resembled a kind of mold. We noted that the smell was less putrid than last week and we hypothesized that the smell and visual appearance will change from week to week based on the growth of organisms in the container. The Archaea species which we removed from this culture grew on our agar plates because they have had ample time to grow and multiply.
The plates with antibiotic are not much different from those without it, however it is clear that those with antibiotic produced slightly less bacteria than those without. This indicates that tetracycline does not have a very powerful effect on the growth of bacteria and actually promotes the growth of fungi, as we saw in plate 10^7 with tet. There are several species of bacteria unaffected by tetracycline due to their ability to mutate and reproduce. "Tetracycline works by binding specifically to the 30S ribosome of the bacteria, preventing attachment of the aminoacyl tRNA to the RNA-ribosome complex. It simultaneously inhibits other steps of the protein biosynthesis (Klajn, n.d)." Source: Klajn, R. (n.d.). Antimicrobial Properties. (Bristow University) Retrieved from Tetracycline- Chemistry and chemical Biology of Tetracyclines: http://www.chm.bris.ac.uk/motm/tetracycline/antimicr.htm
Procedure III: The bacteria we observed from both our wet mount and our gram stain seemed to be tiny pill shaped organisms that move slowly in a general direction as a group. Some of the bacteria did not move. Because they were so small it was hard to tell whether or not they had flagella or cillia.
For the wet mount procedure, we sterilized a loop over a flame and scraped up a tiny piece of bacteria colony from one of our plates. It was mixed into a drop of water and then put the slide back over the flame until the water evaporated. We then placed a cover slip placed on top. We attempted to view the organisms at 10x and 40x. The bacteria were visible at 40x but were very tiny. For the gram stain procedure, we did the same steps as the wet mount but did not put on a cover slip immediately. Instead we used a straining tray and covered the bacteria smear with crystal violet for one minute. It was then rinsed with a wash bottle of water. Next, the bacteria sample is covered with grams iodine mordant for one minute and again rinsed. We decolorized sample by flooding 95% alcohol for 15 seconds. The smear is covered with safranin stain for 25 seconds and rinsed immediately. We blotted excess water with a paper towel and allowed it to air dry completely. It was then ready to be viewed under the microscope.
Procedure IV: For our PCR reaction we labeled 2 tubes with our transect number, colony and group number. We added 20 microliters of a primer water mixture that dissolved the PCR bead at the bottom of the tube. We then mixed the contents for 5 seconds with a toothpick and placed the cap on the tube. It is then placed in the PCR machine.
Conclusion In conclusion, we have discovered that there are several types of antibiotic resistant bacteria caused by mutations in DNA during evolutionary processes. We observed a few different types of these bacteria from our Hay Infusion culture through gram staining and microscopy in order to identify their species through observation of morphology, motility, and finally PCR.