AQA GCSE Biology Biology Paper 2 (Foundation), June 2024: Question 9

✅ Correct Answers

Any one of the following:

• A change in the DNA
• A change in the base sequence (or nucleotide sequence)
• A change in a gene or allele
• A change in the number or structure of chromosomes

❌ Common Errors & Mark Scheme Traps

• "A change in genetic information" — Ignored by examiners as it is too vague.
• "A change in a protein / amino acid" — Ignored; a mutation occurs in the DNA itself, not the protein product.
• Confusing mutation with variation.

✅ Marking Points (Any 3)

1. There is variation between members of a species.
2. Organisms with characteristics best suited to the environment are better adapted and survive ("survival of the fittest").
3. The surviving individuals reproduce.
4. They pass on their favourable alleles / genes to their offspring.

🧠 Exam Technique: Use the "V.S.R.G." Framework

Always write natural selection answers using four sequential keywords:

• V – Variation exists in the population.
• S – Better adapted individuals Survive.
• R – Survivors Reproduce.
• G – Favourable Genes / alleles are passed on.

❌ Lost Marks to Avoid

• "Pass on characteristics / traits": Examiners explicitly ignore this. You must state they pass on genes or alleles.
• Stating "animals choose to adapt" or "they adapt over their lifetime" (Lamarckian idea — 0 marks).

💡 Key Term Distinction

Gene vs. Allele: An allele is a version of a gene. A mutation creates a new allele that gives a survival advantage in that specific environment.

✅ Correct Answer

[✓] Alfred Wallace and Charles Darwin

Darwin and Wallace jointly presented their theory of evolution by natural selection to the Linnean Society in 1858.

💡 Who Were the Other Scientists?

• Alexander Fleming: Discovered penicillin (the first antibiotic) in 1928.
• Carl Woese: Proposed the three-domain classification system (Archaea, Bacteria, Eukaryota) based on RNA analysis.

✅ Model Answer (3 Marks)

• Mark 1: The hoverfly's yellow and black markings make it look like a wasp (warning colouration).
• Mark 2: Predators (birds/animals) avoid wasps so they do not get stung.
• Mark 3: As a result, predators do not attack / eat the hoverfly.

🧠 Structuring an Adaptation Explanation

To score full marks on mimicry questions, connect all three links in the cause-and-effect chain:

1. Appearance: What does the mimic look like? (Looks like a wasp)
2. Predator experience: Why do predators avoid the model? (Fear of sting)
3. Outcome: What happens to the mimic? (Not eaten / survives)

❌ Examiner Pitfalls

• Anthropomorphism: Do not write "the bird thinks the hoverfly is a wasp" — examiners explicitly ignore statements attributing conscious thought to animals. Write: "the markings are similar" or "it looks like a wasp".
• Vague survival claims: Writing only "it protects them" without explaining that predators avoid eating them to escape being stung loses marks 2 and 3.
• Do not say "predators avoid getting bitten" — the prompt clearly specifies wasps sting.