Unit 3: Continuity of Species

Cell division. Compares mitosis and meiosis stage by stage and explains how crossing over, independent assortment and random fertilisation generate variation.

Changing allele frequencies. Covers the gene pool, genetic drift, gene flow, the founder effect and bottleneck effect, with Australian examples of small and isolated populations.

Natural selection. Covers variation, selection pressures, differential survival and reproduction, fitness, and Australian examples such as cane toad and myxomatosis resistance.

Biotechnology. Covers PCR, gel electrophoresis, recombinant DNA, transgenic organisms, cloning and the ethical and ecological implications.

Gene expression. Covers transcription of mRNA, the genetic code and codons, the roles of mRNA, tRNA and ribosomes in translation, and how the polypeptide folds into a functional protein.

DNA, genes and chromosomes. Covers nucleotide structure, the genetic code, transcription and translation, and how DNA is packaged into chromosomes.

Gene technology techniques. Covers restriction enzymes, recombinant DNA and ligase, the polymerase chain reaction, gel electrophoresis and DNA profiling with their applications.

DNA replication. Covers the semiconservative model, the roles of helicase, DNA polymerase and ligase, leading and lagging strands, and why accurate copying matters for continuity of species.

Mutations. Covers point mutations including substitution, insertion and deletion, frameshift effects, chromosomal mutations, mutagens, and why only mutations in gametes are heritable.

Reproductive and cloning technologies. Covers selective breeding, transgenic organisms, reproductive and therapeutic cloning, and the ethical and biological implications with Australian examples.

Evolution and speciation. Covers natural selection, the gene pool, allele frequency change, isolating mechanisms and how new species form.

Speciation. Covers the biological species concept, allopatric and sympatric speciation, prezygotic and postzygotic isolating mechanisms, and Australian examples of divergence.

How meiosis creates variation. Covers crossing over, independent assortment, random fertilisation, and how these processes combine to make each offspring genetically unique.

Patterns of inheritance. Covers dihybrid crosses, codominance and incomplete dominance, multiple alleles such as ABO blood groups, sex linkage and polygenic inheritance with Australian examples.

Hardy-Weinberg principle. Covers the equations, the equilibrium conditions, worked allele and genotype frequency calculations, and how deviation from equilibrium indicates evolution.

Pedigree analysis. Covers reading pedigree symbols, distinguishing dominant from recessive and autosomal from sex-linked inheritance, and assigning genotypes from a family tree.

Inheritance. Covers Mendelian crosses, codominance, sex linkage, polygenic traits, mutation and the sources of genetic variation.

Evidence for evolution. Covers the fossil record, comparative anatomy and homologous structures, molecular and biochemical evidence, and biogeography with Australian examples.