[longshadow]

Gravity is a law.

The phenomonon of Gravity (objects attract each other) is backed up by a Theory of Gravitation; namely General Relativity.

The phenomonon of speciation is backed up by a Theory; namely the Theory of Evolution.

Both are on equivalent scientific footing.

[Frumious Bandersnatch]

Both are on equivalent scientific footing.

Not really.  Gravity does not have the problems associated with it that evolution does.  A theory never has the same weight as a law.  Which is why there are so many theories and so few laws.  A law is considered incontrovertible, because it has been proven.  A theory is a useful instrument, but it does not have the same level of confidence that a law does.  As an example, while our understanding and knowledge of gravity has changed and improved over the years, the law itself has not changed, however, the theory of evolution is constantly evolving.