28.1
DNA, genes and chromosomes
From cell to gene, the double helix and the scientists who found it, chromosomes in pairs, sex cells and heredity.
28.2
Inheritance and variation
Variation within and between species, genes or environment, continuous and discontinuous variation, and how sex is decided.
28.3
Natural selection
Variation, competition and survival, passing on genes, peppered moths, Darwin and Wallace, and the evidence for evolution.
28.4
Extinction and biodiversity
Extinction, why variation helps a species survive change, causes of extinction, biodiversity, gene banks and protecting species.
Daily 5
Five quick diagram questions a day from this unit. The ones you get wrong come back sooner. Progress saves in this browser.
What this unit covers
Mapped to the KS3 national curriculum (Biology: inheritance, chromosomes, DNA and genes).
| Programme of study | Lesson |
|---|---|
| heredity as the process by which genetic information is transmitted from one generation to the next | 28.1, 28.2 |
| a simple model of chromosomes, genes and DNA in heredity, including the part played by Watson, Crick, Wilkins and Franklin in the development of the DNA model | 28.1 |
| differences between species | 28.2 |
| the variation between individuals within a species being continuous or discontinuous, to include measurement and graphical representation of variation | 28.2 |
| the variation between species and between individuals of the same species means some organisms compete more successfully, which can drive natural selection | 28.3 |
| changes in the environment may leave individuals within a species, and some entire species, less well adapted to compete successfully and reproduce, which in turn may lead to extinction | 28.3, 28.4 |
| the importance of maintaining biodiversity and the use of gene banks to preserve hereditary material before it is lost | 28.4 |