From what I've seen "law", "theory", "rule", "principal", "equation", "rule" etc are not used as rigorous terms in the scientific community. As another poster points out, Ohm's law is far less widely correct than the "theory" of gravity. Remember these are scientists, not lawyers. It is understood that any "law", "theory", etc may be invalidated by the next experiment. Its also understood that "theories" generally come with all sorts of caveats:
The gravitational force between to bodies goes as GM1M2/r^2..... in the limit of non-relativistically weak gravity, in flat space time, over non-cosmological distances. It is understood that this has not been verified when r is small (sub millimeter), and some theories predict non 1/r^2 behavior at short distances. It is expected but not verified that M is always positive, but has not been tested for antimatter.
Similarly the "law" of conservation of energy became the law of conservation of mass-energy (or really 4-momentum), which needs to be clarified in curved space-time. It is widely believed to be correct, but a violation of this or any other conservation "law" would be extremely interesting and is not considered impossible, though very unlikely.
Evolution is a very complex topic. There is a huge amount of evidence to support the general concept of mutation and natural selection, but lots of missing pieces in the details. People should not "believe" in evolution. They should accept that it is a model that is widely supported and has good predictive power. Like any other theory it could be disproved by new evidence. It also does not rule out other forms of species change from Lamarkian evolution to genetic engineering.