In addition to this, the evolution of a genre might see the themes evolve with the society that creates it. Understanding the themes of a text is something which can sometimes demand rigour and analysis. By the same token, recognising the aesthetic conventions of a film may be complicated if the film uses a combination of different genres, known as a hybrid.
This page should help you understand both whilst at the same time give you tips on how to write decent paragraphs of film analysis.