Internal Assessment: Practical Investigation, Validity, Adaptation and Ecology
What the internal domain assesses
The internally assessed Level 2 Biology standards are 2.1 (carry out a practical investigation, 4 credits), 2.2 (analyse the biological validity of information presented to the public, 3 credits), 2.3 (adaptation of plants or animals to their way of life, 4 credits) and 2.6 (investigate a pattern in an ecological community, 4 credits). Assessment is evidence-based: you must show the biological reasoning behind your method, data and explanation, not just produce a polished report.
Core rules
- 2.1 needs a purpose, a hypothesis linked to biological theory, a method that controls variables, repeated measurements or a sufficient sample, processed data (means, graph, trend), and a conclusion linked back to the hypothesis.
- 2.2 requires you to separate a claim from its evidence and judge validity using sample size, method, source expertise, bias and correlation versus causation.
- 2.3 adaptations are inherited features that increase fitness; classify them as structural, behavioural or physiological, and link each to the habitat.
- 2.6 requires a named pattern (zonation, stratification, succession or distribution), sampling data and an explanation using abiotic and biotic factors.
Worked example
A student tests: 'As light intensity increases, the rate of photosynthesis in Elodea increases.' They place pondweed 10, 20, 30 and 40 cm from a lamp, count oxygen bubbles for 2 minutes, repeat three times and use means. Temperature and CO2 are kept constant. The graph shows a rise then a plateau. The conclusion links the initial rise to more light energy for the light-dependent phase and the plateau to a limiting factor such as CO2. Validity is discussed: distance is a proxy for light intensity, and bubble counting is less reliable at high rates.
Traps
Naming variables without explaining how they are controlled; writing a conclusion that ignores the hypothesis; using 'adapted to' without stating the selection advantage; treating a media claim as valid because it cites one expert.