The answer

As several people worked out (first of whom was my Ozzie chum Ross) the link is the brilliant Prussian naturalist Simon Peter Pallas.
The pictures show:

Pallas' Fish Eagle
The city sign of Pallasovka
Pallas' Rosefinch
Lunar crater Pallas
Pallas' LeafeWarbler
A pallasite from the city of Pallasovka
The asteroid Pallas
Pallas' Cat
Pallas' Grasshopper Warbler

All of which were discovered by or named for Herr Pallas!