This is a very apt analogy.
We have a theory of gravity that tells us neither what gravity is nor how it works. We can see things attract one another and that dead individuals don't have off spring. Obviously death attracts all unfit things and all individuals attract either for food or sex. Reality is very simple once you accept the basic principles and begin rushing around in circles. Species change and unfit individuals die. Obviously species are composed only of the most fit and it looks like they are changing so slowly we can never observe it.
It all makes perfect sense. Who needs to know what causes gravity when you can see its effects from tides to every single event everywhere.
Anyone who believes in "gravity" can adopt "evolution". Run it around the block a few times and see if it grows on you. Don't worry if it dies since there's always a fitter and healthier theory coming along.
I didn’t say gravity don’t exist, as there are plenty evidence for gravity, not only on earth, but for every objects in our Solar System, other stars in the Milky Way, and other galaxies in the universe.
Theoretical physicists are still trying to work gravity “at the quantum level”...anyone who can find the solution to “Quantum Gravity” may finally find the answer that combine General Relativity (GR) with Quantum Field Theory (QFT), the so-called “Theory of Everything” that even Einstein couldn’t solve.
There are number of unanswered questions to physics and mathematics...that remained to be solved.
But biology on Earth, is better understood, including Evolution, and tested.
There are even more than testable evidence to support the various evolutionary mechanisms (mechanisms like Mutations, Genetic Drift, Natural Selection, Gene Flow & Genetic Hitchhiking, have all been tested).
Do I think it is possible for biologists to find alternative answers to biodiversity of life?
My answer would be:
SURE, but until someone can present testable alternative that meet with past and present evidence, as well as backed by any future evidence, the current (modern) evolutionary biology hasn’t been refuted.
It will take time...People, whether it be physicists or biologists can always generate theoretical framework or hypothesis...but sometimes it could take decades or even a century or more, to find some ways to test the theoretical framework or hypothesis.
Take Peter Higgs and other theoretical physicists coming up with theoretical hypothesis that explain particle mass generation of other particles (the Higgs Boson), way back in 1964 (for Higgs).
It was only in 2013 that they were able to test the Higgs Mechanics, using the Large Hadron Collider at CERN. That’s almost 50 years.
Now, there may well be alternative to the current theory of Evolution, but some biologists have offered some alternatives, but so far, these alternatives have fallen short in the testing department.
I am “open” to alternative solutions to physics fields or to biology fields, and to other sciences, but until they are testable and more importantly tested, these alternatives aren’t “science”.