4. Inheritance and selection
4.1 Variation
Define variation as differences between individuals of the same species.
Discuss the causes of genetic and environmental variation.
Describe continuous and discontinuous variation.
Design and conduct an investigation to measure continuous and discontinuous variation.
Collect and analyse data, presenting it in the form of tables and graphs.
4.2 Genes, chromosomes and alleles
Define the term gene as a length of DNA that codes for a protein.
Define a chromosome as a thread-like structure of DNA, carrying genetic information in the form of genes.
Describe DNA (deoxyribonucleic acid) as the molecule that makes up genes and chromosomes and carries genetic information inherited from parents.
DNA - The recipe for life
4.3 Dominant and recessive alleles
Describe the difference between dominant and recessive alleles.
Use genetic diagrams to predict the results of monohybrid crosses and calculate phenotypic ratios, limited to 1:1 and 3:1 ratio.
Interpret pedigree diagrams for the inheritance of a given characteristic.
Describe the symptoms of cystic fibrosis and use pedigree diagrams to determine the chances of offspring inheriting disease of parents.
Dominant and recessive alleles
Punnett squares
Pedigree diagrams
Inherited diseases
4.4 Selective breeding
Describe how farmers can use natural selection to increase desirable traits in animals.
Describe how farmers can use natural selection to increase desirable traits in plants.
Outline the advantages and disadvantages of selective breeding
4.5 Adaptive features
Describe what is meant by an adaptation and give examples of how animals are adapted to different environments
Adaptive features
4.7 Natural selection
Describe how organisms can adapt to environmental change
Discuss the work of Darwin in developing the scientific theory of natural selection.
Discuss how natural selection changes the gene frequencies of a population and leads to adaptation to the environment.
