IB Biology Extended Essay Exemplar
To what extent do varying concentrations of Kalanchoe (Bryophyllum pinnatum) extract inhibits the proliferation of K-12 Escherichia coli and Staphylococcus aureus in LB Agar Petri dishes?
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Criteria A: Focus and Method
6/6
0
3
6
Criteria Strands
Research question is sharply formulated and consistently revisited, demonstrating sustained focus.
Introduction communicates the topic accurately with comprehensive explanation of key terms and context.
Methodology is detailed and justified, providing clear evidence of thoughtful and effective selection of protocols.
Minor lapses in the background narrative (unfinished sentence) interrupt flow.
Exact filter-paper diameter is omitted and choice of LB versus Mueller–Hinton agar is not fully explained.
Criteria B: Knowledge and Understanding
5/6
0
3
6
Criteria Strands
Source material is generally well integrated into the discussion, with clear relevance to the investigation.
Terminology and scientific concepts are used accurately and consistently throughout the report.
Some passages rely on lengthy paraphrase and links between cited mechanisms and the student’s data remain superficial.
Statistical terminology is occasionally conflated (r vs r²) and regression outputs are misreported.
Criteria C: Critical Thinking
6/12
0
6
12
Criteria Strands
Data are analysed with clear relevance to the research question, showing good organisation and interpretation of concentration–response relationships.
Evaluation is thoughtful and supported by multiple literature comparisons, with plausible explanations for discrepancies.
Argument development is coherent with logical progression from results through discussion and conclusion.
Error propagation is oversimplified; more rigorous statistical treatment (e.g., root-sum-square) is needed.
The absence of inferential statistics (t-tests/ANOVA) limits the strength of conclusions.
Criteria D: Presentation
4/4
0
2
4
Criteria Strands
Report structure is clear and follows the expected format with consistent headings, facilitating readability.
Most formatting conventions are met, including title page, word count, page numbering, and labelled tables/figures.
Several tables and graphs suffer from misaligned columns, missing axis labels, and inconsistent captions.
Integrated elements (e.g., mixed text and images in a single table) compromise standalone readability.