Succulents and (tele)protection mechanisms

My wife and I cultivate succulents, plants that store water. Cacti are succulents, but we don’t collect them – only the cuddly and outwardly types. What I find so interesting about succulents is that the various types are relatively unrelated – there was never a proto-succulent that evolved into many subspecies. Instead many different kinds of plants developed similar mechanisms to cope with the