BIOL 1209 Lecture Notes - Null Hypothesis, Cyanobacteria, Chlamydomonas
BIOL 1209
Lab Report
Cover Sheet
I certify that the writing in this assignment is my individual work and is my sole intellectual
property. It does not contain the ideas, or writing of other individuals/authors.
Mia Midori Miyagi April 12, 2017
Author Date
Gabela Nelson Section 17
Lab Instructor Lab Section #
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The Effects of Gas Exchange on the Population Growth of Chlamydomonas in the Lab and
Aquatic Autotrophic Organisms in the University Lake
Introduction:
How will gas exchange effect the population growth of Chlamydomonas and how do pH levels
in the University Lake effect chlorophyll abundance during the fall, summer, and spring from
2015 to 2018? The effect of gas exchange on the population growth of Chlamydomonas was
tested in a population ecology experiment. The null hypothesis for this experiment is that gas
exchange will not show a change in the population growth of algae. The alternative hypothesis is
that gas exchange will show a change in the population growth of algae. The organism
Chlamydomonas reinhardtti is the most widely used laboratory species. Deriving energy from
photosynthesis, with an alternative carbon source, C. reinhardtti can also thrive in total darkness
(About Chlamydomonas). Abiotic factors such as the availability of gas exchange can affect the
growth of photosynthetic organisms. The population growth is dependent upon various abiotic
and biotic factors such as light, nutrients, and predators. We decided to test the algae in three
different gas exchange environments. The effect of pH levels in the university lake on the
chlorophyll abundance during the fall, summer, and spring from 2015 to 2018 was tested in a
community ecology experiment. The null hypothesis for this experiment is that pH levels will
have no effect on the chlorophyll abundance in the university lake during the fall, summer, and
spring from 2015 to 2018. The alternative hypothesis for this experiment is that pH levels will
have an effect of the chlorophyll abundance in the university lake during the fall, summer, and
spring from 2015 to 2018. Chlorophyll is a green photosynthetic pigment found in plants, algae,
and cyanobacteria. Chlorophyll absorbs mostly in the blue and to a lesser extent red portions of
the electromagnetic spectrum, hence its intense green color. Green substance in producers that
traps light energy from the sun, which is then used to combine carbon dioxide and water into
sugars in the process of photosynthesis chlorophyll is vital for photosynthesis, which helps plants
get energy from light (chlorophyll). We decided to test the abiotic factor of pH and how
chlorophyll abundance will change over the fall, summer, and spring from 2015 to 2018.
Methods:
For the population ecology experiment, we first collected nine sterile culture tubes, labeled all
the tubes using a permanent marker in the top one third of the tube. All tubes should have your
initials, section number, and replicate information (one each: A-1, A-2, A-3, B-1, B-2, B-3, C-1,
C-2, C-3). Then, we pipetted one mL of Chlamydomonas culture into all tubes. Next, we pipetted
4 mL of Min (minimal media, a mixture of nitrates, phosphates, and trace metals) into all tubes.
Three treatments each had three replicates. The first treatment was the control and was labeled
A-1 through A-3. This treatment had free gas exchange so the top of the test tube was left
unsealed. The second treatment was limited gas exchange, so the test tubes were labeled B-1
through B-3, and they were covered in Parafilm, which was punctured with one pinhole. The
final treatment was no gas exchange, and the test tubes were labeled C-1 through C-3. These test
tubes were sealed with Parafilm. Finally, we placed the control tubes under fluorescent lights at
room temperature, replaced plastic wrap loosely over the rack, recorded rack and space numbers
and calculated the density of Chlamydomonas in the tubes using the standard curve.
In the community ecology experiment, we collected samples from each lake and recorded the pH
and Chlorophyll Absorbance. In order to find the pH levels, we performed readings on both
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Document Summary
I certify that the writing in this assignment is my individual work and is my sole intellectual property. It does not contain the ideas, or writing of other individuals/authors. The effects of gas exchange on the population growth of chlamydomonas in the lab and. How will gas exchange effect the population growth of chlamydomonas and how do ph levels in the university lake effect chlorophyll abundance during the fall, summer, and spring from. The effect of gas exchange on the population growth of chlamydomonas was tested in a population ecology experiment. The null hypothesis for this experiment is that gas exchange will not show a change in the population growth of algae. The alternative hypothesis is that gas exchange will show a change in the population growth of algae. Chlamydomonas reinhardtti is the most widely used laboratory species. Deriving energy from photosynthesis, with an alternative carbon source, c. reinhardtti can also thrive in total darkness (about chlamydomonas).
