While not platypuses, dolphins or whales, the following links show that speciation (the creation of new species through random mutation and selection) has been observed. The general idea is, what holds true for a sampling of species probably holds true for all species.
Meddle not in the affairs of dragons, for you are crunchy and taste good with ketchup.
The reality is that there are massive gaps in even the theories of how species allegedly involved.
There is NO evidence and no fossil record. Evolution contradicts therodynamics and is based on the absurd idea that mutations are massively beneficial. It's a crock of BS that's even more absurd than global warming.