Biology — How Species Change Over Time
Learn Darwin's theory of evolution: what natural selection is, why genetic variability is needed for it to work, the classic example of the Galápagos finches, and where Lamarck got it wrong before Darwin. Questions adapted to Secondary and Sixth Form.
Biology · Secondary, Sixth Form
Individuals with traits that help them survive reproduce more, and those traits pass to the next generation. Repeated over generations, the species changes.
On the Galápagos Islands, Darwin observed finches with differently shaped beaks, each adapted to a type of food — the visual evidence that helped build the whole theory.
Lamarck thought an individual changed during its life and passed that change on (the giraffe stretches its neck). Darwin corrected this: those who ALREADY had a longer neck, through natural variation, survived better.
"A Year 10 student kept mixing up Darwin's theory with Lamarck's. After seeing the question about the giraffe that stretches its neck versus the giraffe that was already born with a long neck, they finally understood the difference between the two theories."
Tricks and techniques to master this topic faster:
Natural selection = the best-adapted survive and reproduce, not simply the strongest.
Without genetic variability between individuals, natural selection has nothing to act on — that's why variation is the foundation of the whole theory.
Darwin published 'On the Origin of Species' in 1859, after observing the finches of the Galápagos Islands.
Lamarck (before Darwin) got it wrong: a trait acquired during life (like stretching a neck) is not inherited. Darwin corrected this with natural selection.
If you are studying Evolution — Darwin and Natural Selection, these curriculum topics complement each other:
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