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You have decided on the topic of your Biology extended essay but don't know how to structure it? We are here to help! In this post, we'll provide essential guidance on content for each section of your EE, drawing from our expertise with IB. While we suggest this framework based on our track record of assisting students in achieving top-rated essays, feel free to tailor the guide below to your preferences.
Biology EE format and structure
The extended essay is a 4,000 words investigation that should consist of the following parts:
Title page and table of contents
On the title page, you will include the topic of your investigation, the research question, the subject, and the word count.
The next page should be the table of contents with all subsections of your essay along with the page numbering.
Introduction
Provide a concise overview of the topic, including details on the organism/compound under study, its applications, and the reacting agents involved (if applicable).
Explain the personal or global significance of the topic, discussing why it was chosen for investigation and its broader importance.
Introduce the experimental reaction, highlighting why it is the most suitable method for the experiment, such as the rationale behind using specific reactants like sugar solution, ethanol, or citric acid.
As seen in this exemplar.
Research question
Clearly state the research question for your extended essay. For example: What is the Effect of Salinity Stress (0, 50, 100, 150, 200 mM NaCl) Measured Through Microscopic (Stomatal Aperture) and Morphological (Leaf Area, Leaf Dry Mass, and Root Length) Characteristics on Pre-Treated Radish (Raphanus sativus) Seeds with Magnetopriming (48 hours)?
Outline both the independent and dependent variables along with their respective units.
Describe the method or instrument used to quantify and measure the dependent variable, and justify why this instrument or method is optimal for assessing the specific dependent variable.
Formulate a hypothesis.
Background information
Provide definitions of different conditions, methods, or reactions that are crucial for understanding your study.
Describe the molecular structure of the main compound under analysis and highlight the properties that make it suitable for the chosen method of analysis.
For organisms, discuss the characteristics that make them suitable for analysis by the selected method, such as cell membrane susceptibility to ethanol.
For consumable molecules, detail their effects on the body and the potential consequences of imbalances in their levels.
Explain the choice of reagent used for reacting with the main molecule, emphasizing the structural or reactive properties that make it suitable for the experiment.
Include relevant chemical equations if applicable and justify the chosen method of analysis, citing reasons for its appropriateness in measuring the dependent variable.
For research based on secondary data, explain the selection and sampling method of the database used, justifying its relevance to the research question.
Ensure that all background information directly relates to the research question, focusing on relevant biology or chemistry concepts rather than tangential topics.
Incorporate diagrams if relevant, provide clear captions and proper source citations, and use in-text citations throughout the background information section.
See here to get a glimpse of the matter.
Variables
Include the independent variable and units. Describe why the range of independent variables was chosen. You should justify why you have chosen these specific values.
Include the dependent variable, units, instrument/method with which it will be measured, and the uncertainty.
List the controlled variables along with their impact on the experiment and the method of control.
You can use this EE for reference.
Equipment
List all the apparatus and equipment needed to conduct the experiment.
You should provide the uncertainties of all relevant instruments (weighing scale, beakers, pipettes, etc.)
Along with the quantities of the materials needed state their concentrations (if applicable).
Check out the equipment section here.
Methodology
You must thoroughly describe and justify your approach to answering the research question.
Write down step-by-step instructions on how to execute this part.
Conduct enough trials to ensure the reliability of your study.
Show awareness of the safety, ethical, and environmental risks of conducting the experiment.
Check out the methodology here.
Results
Prepare a table presenting processed data derived from the experiment.
Incorporate a segment for qualitative data, if applicable, such as color changes or temperature variations.
Validate that all data in tables adhere to the correct number of significant figures and decimal places.
Introduce a sample equation and calculation to illustrate data processing methodologies, covering each type of computation employed (e.g., averaging, CO2 volume calculation, etc.).
When making calculations, have in mind the appropriate notation, uncertainties, significant figures, and SI symbols.
Organize additional processed data into a separate table, accompanied by a numbered caption.
Provide a sample calculation for uncertainty propagation, placing the remaining uncertainties for other values in a dedicated table with a corresponding caption. Next, describe the implications of these uncertainties on the data, considering their magnitude and impact on the validity and precision of the results.
Include a graph illustrating the processed data against the independent variable, featuring a descriptive title, axis titles with units, and a caption for the figure.
Following the graph, furnish a paragraph elucidating data trends, such as correlations (positive or negative) and the R^2 value. Interpret the findings.
This EE is worth taking a look at.
Conclusion
Re-state the aim of the essay to refresh the reader's memory.
Provide a statement about the extent to which the research topic has been analyzed.
Clearly state the answer to the research question.
- Use experimental values from the analysis section in the conclusion. For example, directly state how the volume of formed gas increased.
Discuss the R^2 value of the graph (if the data is linear) and how it describes the strength of the relationship between the independent and dependent variables.
Take into account the uncertainties and to what extent they could have influenced the results.
Describe if there are any anomalies in the data, and give reasons as to why these may have occurred.
Compare your experimental values to the literature.
Remember not to introduce any new information in the conclusion.
This is a good conclusion.
Evaluation
You are expected to evaluate your approach to answering the research question.
Discuss the strengths and weaknesses of the entire study. State their relevance and impact on the results.
Take into account personal bias or other factors that could have influenced the findings.
Propose improvements and extensions to your essay. For instance, you could suggest repeating the study on different species or using other reagents.
You can use this essay for reference.
Bibliography and appendices
These parts are not included in the word count.
In the bibliography, you should make a detailed list of all sources used in your investigation in alphabetical order. Decide on one style of referencing.
The appendices will serve as a place for additional tables of data etc. however these can't be the crucial information for your EE.
We are hoping that you found this guide useful! For more inspiration head to the Clastify website and check out the remaining Biology exemplars. You can also see our tips on meeting the Biology EE assessment criteria here.
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