Scientists say that the Galapagos flora and fauna are unique due to the climate, envirnoment elements such as humidity, atmospheric pressure, gravity at the poles, isolation, temperature, rainfall etc... but i on the contrary feel, it is because of isolation alone, these is prehistoric creatures like the crocodile or the cockroach.
http://en.wikipedia.org/wiki/Water_holding_cabbage
http://en.wikipedia.org/wiki/Juniper