You Write The Reviews: Natural Selection, Theatre 503, London

Wales is no longer Wales and indecisive middle-aged men need therapy for fear of choosing the wrong pasta sauce. At first, you don't quite know where you are, or where you might be going in Natural Selection. Here is much of our world and its issues, but skewed, shaken up and remade into an alternative universe that melds ineffectual terrorists with archaeological digs and evolution theory with the material concerns of the consumer age.

But as we jump between scenes, relationships become apparent and a broad theatrical landscape takes shape. A major archaeological find provides the catalyst. The discovery of one of man's prehistoric relatives, a hominid wonderfully christened "Gary", puts West Anglia (as Wales has been rebaptised) in the public eye, all to the displeasure of Vlad, a diehard terrorist fighting for Welsh freedom, but to the benefit of Dr Harris, expert in emerging biotechnologies. Meanwhile, Mr Brain (he of the pasta sauce problem) and his prissy wife, Fenella, are simply looking for the perfect suit to land him the perfect job.

The play dips into multiple genres – science fiction and comedy are the foremost – and the cast respond ably, both in terms of the multiple characters needed as well as the gradual change in tone, as we move from light-hearted scenes to explore the potentially darker and dystopian repercussions of later events. Daniel Rigby, in particular, rings the character changes with ease, appearing as Vlad, a fast-talking retail assistant, an uptight HR manager, and even a waiter.

Ultimately, the evolution theme proves to be the most dominant strand of Paul Rigel Jenkins's piece. Not only in dramatic terms, where the characters' need to change and adapt is made explicit, but also in identifying the shift in modern man's priorities, as he moves towards material concerns and ever-more rigorous selection processes for these. It is survival of the fittest gone awry. This is thrown into sharp comic light when Fenella ever so casually encourages her husband to visualise their sexual relations as rape, in an attempt to induce his more decisive alpha- male credentials. We laugh, but it also prompts the thought: while we are still evolving, is our humanity slipping?

Natural Selection demonstrates 503's resourcefulness in taking on imaginative and demanding plays for its intimate stage. Tim Roseman directs the piece with assurance, managing the space well and deftly handling his cast amid Libby Watson's spare but brilliantly efficient set design.

To 31 May (020-7978 7040)

Edward Fortes, Proofreader, London