Lab Report 2: Plant Competition – refer to Modules 5, 6, & 7 (and associated lab lectures) for guidance as you are writing. Be sure you are reading all attached & module documentation on Blackboard thoroughly, as they contain much of the necessary information required. Be mindful of updates from your lab TA (as always) and listen to any feedback provided to you by your lab instructor verbally, via announcements, or as notes on your graded work.
Reference the “Homework” section of the Module 7 handout for extensive guidance on data calculations and statistical test advice. The challenge here will be for students to critically analyze what types of data they have collected, and figure out precisely which comparisons and statements they wish to make in their results sections.
The broad, central question behind the experiment in Module 7 is “Do competitive interactions affect survival and growth in plants?”
Specific Experimental Questions: 1) How does intraspecific competition (density of seeds grown together) affect plant germination speed, vegetative growth rate, and survival chance in [choose radish, sunflower, or marigold]?
2) How does interspecific and/or allelopathy (species identity of seeds grown together) affect plant germination speed, vegetative growth, and survival chance in [2 chosen plant species]?
Hypotheses: 1)H0- Density of seeds per growth pellet will have no effect on mean plant germination speed, no effect on mean plant vegetative growth rate, and no effect on percentage chance of survival in [single plant species].
“Each student will be responsible for using the WHOLE CLASS data set to address BOTH experimental questions and associated hypotheses in their individual lab reports.”
So be sure that you are answering the intraspecific AND interspecific questions in your lab report, not just the question associated with the group that you collected data for. You will have FOUR HYPOTHESES in your lab report (two null two alternative).
1)HA- Density of seeds per growth pellet will have an effect on mean plant germination speed, will have an effect on mean plant vegetative growth rate, and will have an effect on percentage chance of survival in [single plant species].
2)H0- Species identity of seeds growing together in the same growth pellet will have no effect on mean plant germination speed, no effect on mean plant vegetative growth rate, and no effect on percentage chance of survival in [any two plant species].
2)HA- Species identity of seeds growing together in the same growth pellet will have an effect on mean plant germination speed, will have an effect on mean plant vegetative growth rate, and will have an effect on percentage chance of survival in [any two plant species].
Given the specific questions, the specific hypotheses addressing them, and the experimental metrics students have been tasked with measuring, each individual student is responsible for writing a lab report using the ENTIRE shared class data set accessed via the link shared by your TA.
Formal lab reports will be typed and submitted only as a .pdf, .doc, or .docx file and only through this assignment portal by the posted deadline. SafeAssign (plagiarism detection software) is enabled. We understand that since data is being shared within each lab section, a certain amount of “overlap” between reports is inevitable in data and graphs; however, all narrative sections like abstracts, introductions, methods, discussions, figure captions, etc… should be in your own individual words. THIS IS NOT GROUP WORK. Turning in a report that is in any way identical to your lab partners or to another class member is considered plagiarism.
Be sure to include the following in your report. This is a non-exhaustive list, so be sure to refer to the attached document titled “BISC 1112 Lab Report Evaluation Criteria.docx” for the general guidelines/general inclusions in a standard lab report:
1. Inclusion of both broad and specific experimental questions, all hypotheses (null and alternative), all performed protocols, and the ENTIRE data set generated for the experiment (s)… in all aspects of the lab report unless otherwise noted.
2. Title page/Abstract should include an informative report title (NOT just Module 6 title), submitor’s name as it appears on Blackboard, course designation & number, submission date, lab section number/lab instructor name, and names of all group members. Abstract: 200-300 words succinctly stating experiment purpose, key findings of experiment, relevance of findings, and major conclusions.
4. Introduction section should include the given experimental questions and the generated null & alternative hypotheses clearly and correctly stated. Convey to the reader the purpose of experiment & include a brief summary of known facts and background information (with citations from peer reviewed sources). In other words, what information must you include so that the naive reader understands your report? Seek to demonstrate a clear understanding of the big picture i.e… why is this question important/ interesting in the field of biology? It would be appropriate to include well-cited background information on the plants used in the experiment, inter- and intraspecific competition in plants, how resource limitations affect growth and survival in plants, allelopathy, etc… 400 words minimum
5. Methods section MUST NOT have a separate materials list. These should be written narratively, in the third person passive voice, and should include all the materials used. This is the section where you should be most heavily citing the lab module handouts for any of the protocols you used to conduct this experiment and collect/calculate your data. Paraphrase from the module in enough detail that a completely naive scientist would be able to replicate your experiment and get the same results. ALL actions taken in the follow through of this experiment must be included, which includes how you coordinated with your group for data collection, preparation for an execution of the protocol, data calculations, and statistical analyses. Here, you are telling the reader, HOW you did these things, not telling them what precisely you found
6. Results section must include appropriate graphical presentation of ALL the collected data. Think carefully about what type of data you are collecting, what the important trends in the data are and how best that would be conveyed to a reader. Graphs must have a figure legend and informative caption located below the figure, be appropriately formatted, and be fully labeled. Since you measured three different metrics in this protocol, addressing two different hypotheses, you should have at least six (6) different graphs encompassing all class-level data. Here is a simple resource for determining what type of graph to use based on your data https://nces.ed.gov/nceskids/help/user_guide/graph/whentouse.asp (though for this experiment, the professor recommends boxplots and/or bar graphs).
7. Results section must also include a table or tables of the raw data used to generate the graphs chosen. Tables must have a figure legend and informative caption located above the figure, be appropriately formatted, and be fully labeled. All graphs and tables should be constructed in Excel, which the university provides to students for free (https://it.gwu.edu/microsoft-365).
8. Results section must include a series of appropriate statistical tests for the experiment conducted and data collected. Results of stat tests have a specific way they should be reported. In essence, you state what you found and then embed your calculated statistic and p value right at the end of that sentence. T test example: “There is a significantly faster reaction rate for an enzyme concentration of 10 μM compared to an enzyme concentration of 3 μM (𝑡(4) = 5.72, 𝑝 = 0.0046).” In this example, the 4 in parentheses after the degrees of freedom, the 5.72 is the calculated t value, and the 0.0046 is the calculated p value which we are looking to be less than 0.5 to determine significance. Chi square results are presented and assessed similarly: X2 (degrees of freedom) = calculated chi-square statistic value, p = calculated p value (or table p value). The fastest and easiest way to perform most statistical tests is with the Analysis ToolPak in Excel (https://support.microsoft.com/en-us/office/use-the-analysis-toolpak-to-perform-complex-data-analysis-6c67ccf0-f4a9-487c-8dec-bdb5a2cefab6).
9. Results sections ARE NOT just graphs, tables, and captions. Those are all accompanied by narration written in sentences and paragraphs which contextualize the data and results. Here, you describe and emphasize the interesting/important trends in the data, and write out in one or more sentences the results of your statistical analyses. ANY statement you make that references significant trends in the data must be accompanied by the results of a statistical test. For example, if you want to say that germination speed of radish seeds was significantly faster than germination speed of marigold seeds across all treatments, you need to report the results of the series of t-tests you performed which determined that. **Students are REQUIRED to make a minimum of two (2) such statements supported by a minimum of two (2) statistical analyses per metric (one addressing the intraspecific hypothesis and one addressing the interspecific hypothesis). That is a minimum of six (6) statistical tests to report; however, students are obligated to perform as many statistical tests as needed to make the statements they wish to make in their results section.**
10. Discussion section should include whether the null hypothesis is accepted or rejected (can also say alternative hypothesis supported); discussion of experimental design and supporting research; and explain data/research presented that supports conclusion about null hypothesis. Students should suggest further experiments/modifications of the experiment if the hypothesis was to be retested for some reason. Make sure to include discussion of the significance of confounding factors. A sound conclusion must be clearly and logically drawn from data provided in the report with a logical chain of reasoning from hypothesis to data to conclusions that is clearly and persuasively explained. Conflicting data, if present, must be adequately addressed. Limitations of the data and/or experimental design and corresponding implications discussed (including speculation of what might have “gone wrong” for data that does not fit expectations). Relevant and reasonably complete discussion of how this research project relates to others’ work in the fields of resource limitations affecting fitness, competitive interactions/allelopathy within plants in particular (scientific context provided WITH SUPPORT FROM PEER REVIEWED CITATIONS). 400 words minimum.
11. When accepting and rejecting null hypotheses that include multiple metrics (ie… germination speed, vegetative growth rate, chance of survival, etc…), researchers often must make multiple, nuanced hypothesis statements. For example, your data may show that there is a significant difference between germination rates across treatments, but that vegetative growth rates were not significantly different. In such an event, your “reject” or “fail to reject” the null hypothesis statements in your discussion section will be multifaceted and nuanced.
12. Your discussion should also include your thoughts on how you MIGHT be able to differentiate between interspecific exploitation competition vs allelopathy. If students believe they can differentiate between the two phenomena with the data they have, then show those results in your results section and address them in your discussion. If you think modifications to the protocol must be made for that to be possible, then explain how.
13. Include at least three (3) peer-reviewed sources in your lab report IN ADDITION TO a citation of the lab module itself (which is not peer reviewed). The textbook DOES NOT count as a peer-reviewed source either, so use the resources introduced in class to find relevant peer-reviewed journal articles to cite. The following is how I want you to cite the lab Module in APA format:
“Manubay, J. A. (2024). BISC 1112 Lab Module 7: Plant Competition. (p. 1-16). George Washington University. ”
14. Remember to cite in-line in (Author, Date) format AND in the overall reference list for the report in APA style, in alphabetical order.
15. In terms of overall lab report format, be sure to use formal scientific diction, appropriate grammar, punctuation, & syntax throughout the report. Fonts should be 12 point and either Times New Roman, Calibri, or Arial. The report should be typed and legible, double spaced, and submitted to this Blackboard assignment portal as a .pdf, .doc, or .docx file type ONLY. No other file types are acceptable and they will earn you a zero
Refer to the “BISC 1112 Lab Report Evaluation Criteria.docx” document for other specific items to include and further details. Be sure to regularly check the announcements section on Blackboard for any additional information or guidance your lab instructor provides the class.
What we are looking for in your statistical analyses is one test for each metric addressing each hypotheses set (intra/inter) for a total six statistical tests. For example:
– t-test comparing pellets with 2 and 6 of the same seed type for mean # of days it took to germinate for intraspecific data (does seed density significantly impact germination for plants of the same species?)
– t-test comparing the marigold and sunflower mean # of days it took to germinate in the 6-seed pellets for interspecific data (is there a significant difference between the germination of seed types due to interspecific competition?)
then you would do two tests for final mean height and two tests for percent survival.
There are TONS of options for things you can compare in your tests, there just needs to be a minimum of 6 results that you report and there has to be one for each metric for each experimental group (intra hypotheses/inter hypotheses). You are also expected to make figures again for this lab report and you must cite the plant competition module in your methods section and reference list or you will receive a 0 for plagiarism.
