lesson
Evolutionary explanations use multiple lines of evidence
1 · Learn
Inherited variation and differences in reproductive success can change populations over generations. Fossils, comparative structures and molecular similarities can contribute evidence about relationships and change. Classification can be revised when new evidence improves understanding.
An individual does not evolve a needed inherited feature during its lifetime simply through effort. Distinguish selection acting on variation from the origin of new genetic variation.
2 · Worked example
A resistant variant can become more common when susceptible individuals leave fewer offspring under a particular selection pressure; the pressure does not mean every individual deliberately changes.
3 · Your turn
Why is evidence from several independent sources useful when evaluating an evolutionary relationship?
Check your answer
Agreement across different evidence types can strengthen the explanation and reveal weaknesses in one source alone.
4 · Apply your learning
Compare a fictional fossil pattern and molecular comparison, stating what each can and cannot establish.
Adult guidance and safety
Use supplied evidence and approved models. Practical work needs qualified supervision, risk assessment and suitable equipment. No independent chemical, mains-electricity, radiation or biological-culture experiments. Human biology is general education, not personal medical advice; do not request intimate or health disclosures.
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Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
Powers, roots and trigonometry · Year 7 onward
Use only when the task allows a calculator. Choose one operation at a time and record your working. Trigonometry here always uses degrees (DEG), not radians. Inverse sine, cosine and tangent return an angle, not a reciprocal. Keep exact fractions and π in answers when requested.
Approximate numerical results use up to 12 significant digits. Inverse sine returns −90° to 90°, inverse cosine 0° to 180°, and inverse tangent −90° to 90°; these are principal values, not every possible solution of a trigonometric equation.
My observation notebook
Follow your teacher's approved method and safety instructions. Record the sample or supplied dataset, conditions, measurements with units and uncertainties where appropriate. Distinguish observations from explanations. A described experiment is not permission to carry it out; do not improvise equipment or invent missing results.
Ask your teacher for support with the method and recording. A prediction is what you think might happen; an observation is what you actually see, hear or feel safely.
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