What the investigation does
The essay narrows a broad concern about environmental change into three measurable aspects of activity: time moving, changes of direction and separate movement episodes. It observes ten nymphs per trial in a standardized aquarium, changing light, water temperature or pH while identifying the other conditions to control. The introduction links the planned observations to earlier work on aquatic invertebrates.
Graphs, means, standard deviations and Z-tests are used to distinguish differences between conditions. Some temperature and light comparisons support tentative behavioural interpretations, while many comparisons, including those involving pH, do not show significant differences. The evaluation discusses small samples, repeated use of animals, unmeasured light intensity and uncertainty about species identity before declining to claim a consistent overall pattern.
Why this example is worth reading
Defines physical activity through three observable measures instead of using an undefined description of behaviour.
Organizes each environmental variable into parallel results and comparisons, keeping the analysis tied to the research question.
Uses the evaluation to explain how measurement, sampling and laboratory conditions constrain the conclusion.
What the examiner highlights
The examiner credits the extensive, organized and relevant experimental data, despite a limited range of published sources.
The review praises the clear graphical and statistical analysis and the sustained connection between the argument and the research question.
The examiner values the appropriately tentative conclusion, while identifying the limited academic context as the principal weakness.
What to examine critically
The introduction's literature base is limited; the examiner specifically wanted broader research on environmental variables.
Ten specimens per trial, repeated animals and qualitative light levels limit inference; treat the historical procedures and statistical choices as material to evaluate, not an automatic protocol to copy.
Apply it to your own work
Translate a broad biological interest into observable dependent variables and an explicit control table.
Follow each graph with an explanation of what the evidence does and does not establish.
Connect every limitation to its effect on confidence, comparison or generalization.
Essay & assessment material
Read the original material alongside the breakdown, or download it to keep.
The final two PDF pages (29–30) contain the examiner's criterion comments, holistic review and 35/36 total under the historical rubric. The file letter A is an exemplar identifier; no letter grade is asserted.
Source & assessment context
Biology English exemplars, May 2008. The source PDFs retain their original attribution. The analysis on this page is AsterDraft’s independent teaching commentary.
Examiner mark: 35/36 (legacy criteria). The final two PDF pages (29–30) contain the examiner's criterion comments, holistic review and 35/36 total under the historical rubric. The file letter A is an exemplar identifier; no letter grade is asserted.