Our world is a complicated place made up of a complex web of interdependent elements that act upon each other in a plethora of different ways in a multitude of different places creating diverse landscapes, climates and ecosystems. All of this is happening simultaneously at a variety of scales too, ranging from the global right down to the microscopic. Geographers need to be aware if the interconnectedness of all of these systems and scales if they are to understand how the world really works: in short, they need to know everything about everything to do with our planet if they are ever to claim to be the 'perfect geographer'. This is yet to happen and anyone who says that they do understand everything is probably being somewhat economical with the truth!
Due to the complex nature of its subject content, there are a plethora of disciplines that come under the geographical umbrella. Geographers tend to zoom in more on specific types of patterns or particular environments: urban geography, climatology, biogeography, geology, etc. Although the content of the particular geographical sphere may vary dramatically, the basic concept remains the same: patterns and processes; places and spaces.
When we first teach Geography at a primary level we look at big patterns and simple processes which can explain their presence using a couple of 'perfect' examples. But as the pupils go forward on to sixth form and degree level, they soon realise that there are no perfect examples. Their world goes from clear cut black and white to a whole spectrum of greys. Students should not accept knowledge as fact but keep on asking questions. I teach my Y7s and Y8s that they should start to question the knowledge that they are being given now in my lessons and if they are told, for example, "warm air rises", they should ask 'why?'. This takes them into the world of physics, but the pure sciences have always been consider a tool for geographers to apply more usefully in the real world.
Further on up the academic ladder the postgraduate students zoom in even further on a particular part of a particular pattern and the myriad of processes at work to create it.
In effect geography as an academic subject has a fractal nature. A bit like the Mandelbrot set, the closer you zoom in, the more detail you uncover and the more there is to see.
Just a thought ...