The great ideas of biology : the Romanes lecture for 2003

Paul Nurse focuses on four discoveries in 'The Great Ideas of Biology': the cell, the gene, evolution by natural selection, and life as chemistry.

The development of good microscopes made the discovery of the cell possible, although it was not until the later nineteenth century that it was accepted that all living organisms, regardless of their complexity, emerged from a single cell.

The discovery of the gene followed the idea that all living organisms have the ability to reproduce and generate offspring that resemble their parents.

Gregor Mendel's crosses with plants and analyses of the outcomes in the 1860s led him to become the father of genetics, and in the mid-twentieth century DNA was shown to be the genetic material.

Natural selection, the idea of the survival of the fittest, is one of the best-known ideas of biology, proposed by Charles Darwin in 1859.

The idea that many of life's activities can be understood in terms of chemistry had its origins in studies of fermentation, and biochemistry was born when it was shown that an enzyme from yeast cells, i.e. a living organism, was responsible for the chemical reactions that turned grape juice into alcohol.

At that point it was postulated that cells should be understood as a chemical machine. Paul Nurse concludes that the current challenge for biologists is to focus on biological organization which works on a range of levels, from cells through to organisms and ecosystems.