User:Lila Glansberg/Notebook/Biology 210 at AU

Lab 2: Observing and Identifying Algae and Protists--January, 28, 2015

Purpose

The purpose of this lab is to discover and identify any protists living in the transect. This is necessary to further the understanding of ecosystems in the natural world. Students must learn and understand common methods of identifying organisms, such as the use of a dichotomous key. Another purpose of the lab is to prepare for the next class:students will also dilute and plate bacteria that is found in the Hay Infusion Culture.

Materials and Methods

The materials needed for this lab are: -light microscope -dichotomous key -known organism -Hay Infusion Culture (made last class) -micropippetor -four nutrient agar plates -four nutrient agar plus tetracycline plates

Procedure 1: Observe wet mount of a known organism with a microscope. Focus on one organism and describe it and record its size. Use a dichotomous key to determine what the organism is.

Procedure 2: Note the smell and appearance of the culture after bringing it to your desk. Draw samples from two different niches, including some plant matter, and note exactly where in the culture you took the samples from. Observe wet mounts of the samples taken under a microscope, and using the dichotomous key, identify what protists and algae are present. Diagram the organisms observed and measure their size.

Procedure 3: Label four tubes of 10 mL sterile broth with 10^-2, 10^-4, 10^-6, and 10^-8. Set a micropippetor to 100 microliters. Obtain four of each kind of agar plate--label all of the tetracycline plates with "tet." Label each of plate with their respective numbers, and add your lab group's info on the plate. Swirl the Hay Infusion Culture--with the lid on-- to mix up the contents. Add 100 microliters from the culture to the tube labeled 10^-2. Mix the tube thoroughly. Add 100 microliters of broth from this tube to the 10^-4 tube and swirl to mix well. Repeat this twice to make the 10^-6 and 10^-8 test tubes. Pipette 100 microliters from each tube onto their respective nutrient agar plate (10^-2 goes on the plate labeled 10^-3, etc.), and spread it around the plate carefully. Repeat this procedure for each nutrient agar plus tetracycline plate. Place the agar plates in a safe spot in the lab where they will incubate at room temperature. The following is a diagram of the serial dilution procedure:

Data and Observations

The infusion culture smelled like spoiled or rotten vegetables. Its appearance was brown and gooey, with a thin skin on top and soil resting on the bottom. On the top, there formed a network of vein-like structures, in which there floated a fuzzy white clump, about the size of a nickel, two-thirds of which was submerged.

Below is a diagram of the culture as seen from above, and each X represents where a specific sample was taken from.

Sample 1 contained a non-motile species that I was unable to identify with the dichotomous key. It had some green parts, leading me to believe it was a species that performed photosynthesis. It was about 50 micrometers.

Sample 2 contained a variety of organisms, including colpidium, at least two different types of paramecia, and an organism I suspected to be some kind of worm. The colpidium were roughly 50 micrometers, and the paramecia ranged from 70-100 micrometers.

Sample 3 contained more colpidium and various paramecia.

Conclusion

The protists found in the hay infusion culture were both heterotrophs and autotrophs. The consumers are competing for food, while the autotrophs are competing for sunlight to produce their own nutrients with. If the hay infusion culture grew for another two months, I would predict the smell to become more potent, the number of protest species to approach carrying capacity of the ecosystem, and for the white clump to get larger. As each population approached carrying capacity, the selective pressures on each organism would increase: organisms must now be very selectively fit in order to survive, as there is more competition.

LG

Lab 1: A Study of Evolution and Ecosystems at AU--January 25, 2015

Purpose

The purpose of this lab is to begin to understand the different types of life that exist on Earth. It is necessary to understand the basics of evolution before one studies diversity, as all life forms evolved from a common ancestor. By examining a transect of an ecosystem close to home, students can understand the high diversity of life that exists even in small areas.

Materials and Methods

Materials needed for this lab are: -samples of Chlamydomonas, Gonium, and Volvox -light microscope -soil/vegetation sample from transect -water -dried milk

Procedure 1: Prepare wet slides of and observe the three types of algae under a microscope. Note the number of cells contained by each specimen, the colony size, any cell specialization, and motility mechanisms. Note if the organism is isogamous or oogamous. Draw a picture of the organism under the microscope, and note the magnifying power.

Procedure 2: Examine the assigned transect and make a map of the area. Make a list of five biotic and five abiotic specimens within the transect. Take a soil/vegetation sample in a tube to bring back to the lab. This should be what you believe is the most accurate representation of your transect. Back at the lab, prepare a Hay Infusion Culture: Put 10-12 grams of the transect sample in a plastic jar with 500 mL of purified water. Add 0.1 gm of dried milk, place the lid on the jar and mix gently for 10 seconds. Remove the lid and store the jar in a safe place in the lab. Label the jar with your name and transect number.

Data and Observations

The transect assigned to me was farmland in the form of the AU community garden.

Five biotic elements: Cucumber Lettuce Brussel Sprouts Spinach Bushes

Five abiotic elements: Scarecrow Planting box Irrigation system (rubber hosing) Soil Snow

Transect Map:

Conclusion

My transect has many plants growing there, and so I would predict the soil to be full of specimen that make it fertile. I would also expect to see organisms that feed off of plant material. The protists and bacteria I would expect to see would be ones that could survive in the varying temperatures and weather of DC, as well as survive off of the plant material (or fecal matter) that is present in the transect.

LG

January 21, 2015

Photosynthesis is the process of capturing light energy and packaging it as potential energy in the chemical bonds of glucose molecules.

LG