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Heredity and evolution
Science understanding — Australian Curriculum v9.0, Year 10 Science.
Achievement focus
By the end of Year 10, students explain the processes that underpin heredity and genetic diversity and describe the evidence supporting the theory of evolution by natural selection.
AC9S10U01 — Heredity
Students learn to: explain the role of meiosis and mitosis and the function of chromosomes, DNA and genes in heredity and predict patterns of Mendelian inheritance.
Core ideas
- Mitosis produces genetically similar body cells for growth and repair; meiosis produces gametes with half the chromosome number so sexual reproduction mixes genetic material.
- Chromosomes carry genes (sections of DNA); alleles are alternative forms of a gene.
- Mendelian patterns (e.g. dominant/recessive, monohybrid crosses) help predict offspring ratios for simple traits.
Learning checkpoints
In one sentence, how does meiosis support genetic diversity in a species?
Sample answer: It shuffles alleles and halves the chromosome number so offspring inherit new combinations from two parents.Why is DNA described as a “code” for traits?
Sample answer: The sequence in DNA is copied into instructions that cells use to build proteins, which influence an organism’s characteristics.
AC9S10U02 — Evolution by natural selection
Students learn to: use the theory of evolution by natural selection to explain past and present diversity and analyse the scientific evidence supporting the theory.
Core ideas
- Variation in populations, heritable traits, differential survival and reproduction, and time explain adaptive change.
- Evidence includes the fossil record, comparative anatomy (homologous structures), molecular similarities (DNA/proteins), biogeography, and observed change in some populations.
Learning checkpoints
Name two lines of evidence that support common ancestry.
Sample answer: Fossil sequences showing gradual change; similar bone patterns in different species adapted to different roles.How does natural selection differ from an organism “trying” to adapt?
Sample answer: Selection acts on existing variation; individuals do not choose beneficial mutations—advantageous traits become more common because those individuals tend to leave more offspring.