Who created Australia's Coat of Arms after the unification of the states and why? What do the symbols represent?

The Commonwealth Commonwealth Coat of Arms and the Australian national flag on top of Australian Parliament House.

The Australian National flag and Commonwealth Coat of Arms on top of Australian Parliament House.

Parliamentary Education Office (peo.gov.au)

The Australian National flag and Commonwealth Coat of Arms on top of Australian Parliament House.

The Commonwealth Commonwealth Coat of Arms and the Australian national flag on top of Australian Parliament House.

Parliamentary Education Office (peo.gov.au)

Description

This photograph shows the Commonwealth Coat of Arms and the Australian national flag on top of Australian Parliament House.

Thank you for the question. Australia’s current Coat of Arms was adopted in 1912. There is a story that the design of the emu and the kangaroo comes from a Croatian migrant who trademarked it as a logo for his vineyard. 

There are many symbols included in the Coat of Arms.

There is a Coat of Arms on the front of Parliament House, which was designed by an artist named Robin Blau.