Why is genetics now an essential componant of the evolutionary theory?

Question

Why is genetics now an essential componant of the evolutionary theory?

Answer 1

The changing genetics of a population is the easiest way to measure evolution.

Answer 2

The modern evolutionary synthesis is a union of ideas from several biological specialties which forms a sound account of evolution. This synthesis has been generally accepted by most working biologists. The synthesis was produced over about a decade (1936–1947), and the development of population genetics (1918–1932) was the stimulus. This showed that Mendelian genetics was consistent with natural selection and gradual evolution. The synthesis is still, to a large extent, the current paradigm in evolutionary biology.

http://en.wikipedia.org/wiki/Evolutionar...

Perhaps the most significant "formal" achievement of the modern evolutionary synthesis has been the framework of mathematical population genetics. Indeed some authors (Beatty 1986) would argue that it does define the core of the modern synthesis.

http://en.wikipedia.org/wiki/Population_...

Answer 3

resistance to disease is passed on, for example