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4.6 Inheritance, variation and evolution

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How are living organisms classified, and how has classification changed over time?

The Linnaean system of classification, the binomial naming system, how evidence from DNA has changed classification, the three-domain system, and the use of evolutionary trees.
A focused answer to AQA GCSE Biology 4.6.4, covering the Linnaean classification system, the binomial naming system, how DNA evidence changed classification, the three-domain system, and evolutionary trees.
9 min answer →

What is DNA, how is it structured, and what is meant by the genome?

DNA as the genetic material, its structure as a double helix of four bases, the meaning of a gene, chromosome and genome, and how the genome and its interactions are important in medicine and biology.
A focused answer to AQA GCSE Biology 4.6.1.2 to 4.6.1.4, covering DNA as the genetic material, its double helix structure of four bases, the meaning of gene, chromosome and genome, and the importance of understanding the human genome.
9 min answer →

How are characteristics inherited, and how do you work out the offspring of a genetic cross?

The terms gene, allele, dominant, recessive, homozygous, heterozygous, genotype and phenotype, the use of Punnett squares to predict the outcome of crosses, sex determination, and inherited disorders.
A focused answer to AQA GCSE Biology 4.6.1.5 to 4.6.1.8, covering the genetics vocabulary, using Punnett squares to predict crosses, sex determination, and inherited disorders such as cystic fibrosis and polydactyly.
11 min answer →

What is the difference between sexual and asexual reproduction, and what is meiosis?

Sexual and asexual reproduction, the formation of gametes by meiosis, the advantages and disadvantages of each type of reproduction, and the role of fertilisation in producing variation.
A focused answer to AQA GCSE Biology 4.6.1.1, covering sexual and asexual reproduction, the formation of gametes by meiosis, and the advantages and disadvantages of each type of reproduction.
9 min answer →

How do humans change organisms through selective breeding and genetic engineering?

The process of selective breeding and its risks, the process of genetic engineering and its uses, including genetically modified crops and the production of human insulin, and the ethical issues raised.
A focused answer to AQA GCSE Biology 4.6.2.3 to 4.6.2.4, covering selective breeding and its risks, the process and uses of genetic engineering including GM crops and human insulin, and the ethical issues raised.
10 min answer →

What causes variation, and how does evolution by natural selection happen?

The causes of variation (genetic and environmental), the theory of evolution by natural selection, the role of mutation, evidence for evolution including fossils and antibiotic resistance, and how new species form.
A focused answer to AQA GCSE Biology 4.6.2 to 4.6.3, covering the causes of variation, the theory of evolution by natural selection, the role of mutation, the evidence for evolution, and the formation of new species.
11 min answer →