IB Biology Extended Essay: How to Structure and Format it Successfully

Tony is an IBDP Biology teacher, having taught for over 20 years, both in the UK and internationally. He holds  a Micro-Biology BSc from Imperial College, and a Master’s in Education from the IoE. While supervising IB Biology Extended Essay & ESS and IAs over the years, he has learned how to help students get a 7 in IB Biology. .

Article reviewed & updated by Tony, 5th June 2025

Writing the IB Biology Extended Essay (EE) might initially seem overwhelming, but it’s much more manageable with the right approach. The secret is understanding how to structure and format your essay correctly, and to break it down into manageable pieces. 

This guide will walk you through everything you need to know to get organised, stick to the guidelines, and ensure your IB Biology EE stands out as a well-researched, well-written paper that ticks all the boxes.

Why is a well-structured IB Biology Extended Essay so important?

A well-structured Biology Extended Essay (EE) is key to making your research clear and easy to follow. The IB values structure because it helps you present your findings logically, showcasing your critical thinking and scientific analysis. A clear structure also keeps you focused on your research question and methodology, making it easier to build a persuasive argument. Without it, your essay can become disorganised, affecting your marks.

Writing the essay in manageable sections makes the process more efficient, less daunting, and keeps you on track. This approach helps you stay organised, ensuring that each part of your EE meets the IB’s expectations. Tony advises that a “well-structured essay improves readability and enhances the quality of your research and analysis. It helps you stay focused on the EE criteria as you write, making it easier to meet the marking requirements instead of addressing them as an afterthought”.

Structure of the IB Biology Extended Essay: Key Components

When structuring your IB Biology Extended Essay, think of it as splitting the project into workable sections.

Tony, our experienced ESS tutor, uses this approach to break down his students’ Extended Essays into smaller parts.

“One thing I always say to my EE students to make things easier is not to think of it as a huge essay of 4,000 words. The best way to think about it is like this: First, your introduction and the justification for your research question are going to cover around the first 400 words. Second, at the end, your review of your methodology and conclusion, etc, can easily be 600 words. This means you can start thinking of it as a 3,000-word essay, which you will cover in 10-15 subheadings. So, each one will only be 200-300 words. You can think of it as writing 10-15 paragraphs of this size. The project will seem so much less daunting.”

Here are the key components of the essay:

Title Page

The title page is the first section of your EE that your examiner will see, and it sets the tone for the rest of your paper. It should be simple and professional, providing key details about your essay. The title page must include the following:

• Title of the Essay: Choose a clear, concise title that clearly describes the focus of your research.
• Research Question: State your research question directly, making it clear and specific. This is the central theme of your essay, so it must be well-defined.
• Subject: Make sure to specify that the subject is Biology. If your essay is in a different subject area, specify that.
• Word Count: Include the final word count of your essay (excluding the bibliography and appendices).

Avoid cluttering the title page with unnecessary information such as your name or supervisor’s name. Stick to the required elements only.

Table of Contents

A table of contents helps your examiner easily explore your essay. Place it right after the title page, listing all sections and subsections with their page numbers like the introduction, literature review, methodology, results, discussion, conclusion, and references. This keeps both you and your examiner organised, making it simple to locate key sections.

Introduction

The introduction of your IB Biology Extended Essay is your chance to set the stage for your research. In about 400 words, introduce your research question and explain the biological topic you’re investigating. Make sure your research question is focused and specific. Avoid anything too broad. Your goal here is to show why this topic matters, whether relevant to a global issue, scientific exploration, or even your interests.

Don’t forget to provide some context. Briefly explain the biological concepts or systems you’re exploring and why your chosen topic is significant. The introduction should give the reader a clear understanding of your research question and the relevance of your study, setting up the rest of your essay for success.

Literature Review

The literature review is your opportunity to show the context of your research and why it matters. Instead of just summarising previous studies, you need to critically analyse them. Explain how these studies have shaped your understanding and how your research builds on them. This section clarifies your research question, highlights gaps in the existing knowledge, and justifies why your study is important.

Remember to use credible academic sources, such as peer-reviewed journals and textbooks. Always cite your sources properly and include a full reference list in your bibliography. This will show the depth of your research and ensure that your essay follows academic standards.

Methodology

The methodology section is a critical component of your Biology Extended Essay, as it details the experimental procedures you followed in your research. It should be clear, concise, and specific enough for someone else to replicate your experiment if needed.

Describe your methods, including any apparatus, chemicals, or techniques. Explain why these methods were appropriate for answering your research question and how they enabled you to collect the necessary data. If you carried out an experiment, include a clear, step-by-step breakdown of your procedure, highlighting the variables you manipulated and controlled.

When conducting primary research such as lab work or field experiments, be sure to detail how you collected your data—this includes your sample size, number of trials, and control conditions. For projects based on secondary data, describe how you chose your data sources and explain why they are relevant to your research question.

Results

In the results section, you’ll present the data you collected during your experiment or research. It’s crucial that your data is organised and easy to interpret. Use tables, graphs, and charts with clear titles, axis labels, and units to ensure everything is easy to follow. Present both raw and processed data, along with any statistical analyses, but keep it simple and focused on showing the data itself.

Remember, this section is not for interpreting your findings. That’s what the discussion is for. Don’t jump ahead and draw conclusions or make connections between the data points here. Just focus on presenting the facts clearly and logically.

Discussion

The methodology section is an important component of your Biology Extended Essay, as it details the experimental procedures you followed in your research. It should be clear, concise, and specific enough for someone else to replicate your experiment if needed.

Discuss any patterns, trends, or correlations in the data and explain their significance. If your data supports your hypothesis, explain how. If it doesn’t, propose possible reasons why, and consider alternative explanations.

In this section, you should also reflect on the limitations of your research, such as the accuracy of your measurements, sample size, or any potential sources of error. Recognising the weaknesses in your study shows critical thinking and an understanding of scientific processes.

Conclusion

The conclusion is where you provide a final summary of your research findings and answer your research question. Keep it concise and directly related to the data you’ve presented. Avoid introducing new information in this section; instead, reflect on what your results mean in the context of your research.

You should also discuss the broader implications of your findings and suggest areas for future research or improvements to your methodology. Make sure to mention any unanswered questions or unresolved issues that arose during your investigation.

References and Citations

Your references and citations are vital for crediting the sources you’ve used in your research. Use proper citation styles (MLA, APA, or Chicago) throughout your essay to reference all books, articles, and other sources.

Many students make the common mistake of not keeping track of citations as they go along. Tony advises, “Falling into this trap means you have a huge job at the end to find each reference. So make sure you do it as you go along.” This saves you time and ensures that your citations are accurate.

The bibliography should list all sources you have cited in alphabetical order, formatted correctly according to your chosen citation style. Be sure to double-check your references for accuracy.

How to Format the IB Biology Extended Essay

The formatting of your IB Biology Extended Essay must be consistent with the IB’s guidelines. Here are the basic formatting requirements:

• Font: Use a readable, professional font such as Times New Roman or Arial in 12-point size.
• Spacing: Your essay must be double-spaced throughout.
• Margins: Standard 1-inch margins (or 2.5 cm) on all sides.
• Page Numbers: Page numbers should be placed at the top-right corner of each page, starting from the Table of Contents.
• No Personal Details: Do not include your name, candidate number, or your supervisor’s name on the title page or headers.

Common Mistakes in Structure of the IB Biology EE

While the structure of your IB Biology Extended Essay is straightforward, it’s easy to make mistakes. Here are a few common ones to avoid:

1. Unclear Research Question. The research question should be specific and focused. Vague or broad questions will make it difficult to stay on track and gather relevant data.
2. Poorly Organised Data. When presenting data, ensure everything is clearly labelled and easy to interpret. Tables and graphs should have appropriate titles and axis labels.
3. Weak Literature Review. A literature review that is too brief or doesn’t provide enough context may be difficult for the reader to understand the significance of your research.
4. Missing Citations. Always keep track of your sources from the beginning. Failure to properly cite your sources can result in plagiarism.
5. Inadequate Discussion. Your discussion should analyse the results critically. Don’t just restate the findings; explain why they are significant.

FAQs

How to choose the right research question?

Choosing the right research question is crucial for your IB Biology Extended Essay. It should be specific, researchable, and relevant to the field of biology. Focus on a question that interests you and can be investigated using available resources. Tony recommends that your question should be narrow enough to allow for a thorough investigation but broad enough to provide enough material for analysis.

What are the best ways to present results in IB Biology Extended Essay?

The best way to present results is through clear tables, graphs, and charts. Use graphs to show trends and comparisons, ensuring that they are well-labelled and easy to understand. Include captions to explain what the data represents. Make sure to provide sample calculations and include a discussion of any uncertainties in the data.

What type of sources should I use for my IB Biology EE?

Tony advises his students to use Google Scholar. “For this level of academic writing, it’s a good idea to use sources of an appropriate level using Google Scholar. This has the added benefit of having a one-click method for creating citations and copying them into your essay,” says Tony. Be sure to select peer-reviewed journals and reliable sources to back up your claims.

How should I format the title page and abstract?

The title page should include the essay’s title, research question, subject area (Biology), word count, and your IB candidate number. The abstract, though not part of the word count, should summarise the key points of your essay, including the research question, methodology, results, and conclusions.

How do I format my Extended Essay correctly?

Your IB Extended Essay should follow a consistent format with clear headings and subheadings for each section. Ensure that you adhere to the word count and include all required sections: title page, table of contents, introduction, literature review, methodology, results, discussion, conclusion, and references.

Need Help Writing Your IB Biology Extended Essay?

At TutorsPlus, we know how overwhelming the IB Biology Extended Essay can feel, and we’re here to help you every step of the way. Our experienced IB Biology tutors, who are also teachers and examiners, offer personalised support, whether you need help choosing the right research question, refining your methods, or reviewing your essay’s structure and content. 

Here are some testimonials from the students who appreciate the guidance we provide:

“Jonathan has been super helpful through my process of writing my EE, would absolutely recommend his support to IB students.”

“I thought Sebastian was very helpful in providing me advice on an IB essay I am working on. His feedback gave me clear, specific details of how to improve, and he also gave me reliable secondary resources to develop my ideas further. He seemed to put a lot of time/effort to support me.” – Lucy

Writing your EE doesn’t have to be a solo struggle. With TutorsPlus, you’ll have expert support from start to finish. Contact us today at +41 022 731 8148 or . We’re ready to help you achieve your goals!