I think the notion that convergent evolution will make alien life resemble earth life can easily be taken too far. Of course laws of physics, and their derivatives fluid dynamics and mechanics of materials will likely operate exactly the same way across the universe. So a streamlined pisciform shape is likely to be common amongst large motile organisms that live in a dense fluid, or a very rapidly moving organisms that live in a gaseous environment.
Buy that kind of thing probably represent the limit of likely convergent evolution across totally separate lineages of biological evolution. This is because cases on earth where seemingly different organisms that through convergent evolution came to resemble each other sufficiently closely as to mimic the sort of convergent evolution seen in Star Trek and Star Wars, such as whales and fish, bats and pterosaurs, all evolved from animals that belong to the same phylum and shared identical fundamental body plans.
Buy that kind of thing probably represent the limit of likely convergent evolution across totally separate lineages of biological evolution. This is because cases on earth where seemingly different organisms that through convergent evolution came to resemble each other sufficiently closely as to mimic the sort of convergent evolution seen in Star Trek and Star Wars, such as whales and fish, bats and pterosaurs, all evolved from animals that belong to the same phylum and shared identical fundamental body plans.
