What is an example of observed evolution?

Answer 1

There are many thousands of papers, even considering only recent publications, that detail examples of contemporary evolution. Some of these are about experimental evolution, others about observations of evolution in the wild.

The following (fairly recent) paper details one of such observations, in this case about the influences of human settlement on the behavioural and morphological development of populations of blackcaps:

Rolshausen et al, 2009, Contemporary evolution of reproductive isolation and phenotypic divergence in sympatry along a migratory divide, Current Biology 19.

Answer 2

The peppered moth population in England is a well-known example of observed evolution. During the Industrial Revolution, the darkly colored moths became more common than the light-colored moths, as the trees became darker due to pollution, making the dark moths better camouflaged from predators. This change in frequency of different colored moths over generations is a clear example of natural selection and adaptation.