If you are interested in knowing the evolutionary history of your preferred Ensembl gene, you are in luck. Starting from this release (69) Ensembl has a new gene gain/loss tree view just for this purpose. This view shows the evolutionary history of a gene family by showing gains (expansions) or loss (contractions) on the number of members belonging to a given gene family.
The example below shows a detail of the evolutionary history of the human gene ZNF235 as displayed by this new Ensembl view. As you can see, it is a species tree with annotated branches showing significant expansions (in red), contractions (in green) or no significant changes (in blue). The nodes representing each extant species or ancestral node is labelled with the number of members of the family and the statistical significance of this change (or the lack of it).
If you want to know more about this view and how the data is generated check out its help page.
Please, try it out with your preferred genes and let us know your impressions (helpdesk contact form). We are working to include more useful information in the view and your input is important!