One of the criticisms of the theory of evolution is that it doesn't explain everything and you cannot track with preciseness just how one species evolved from another.
While that is a valid criticism, it is also a misleading one. Until very recently, the primary way that species development was tracked was by fossils. That required an animal (I am not getting into plants) to die in a spot where its body could be quickly entombed before scavengers scattered the remains. Then the entombed body had to be slowly
converted into a fossil. Then the fossil has to survive for millions of year and then it has to be found by someone who recognizes what it is.
That's a lot of "ifs" for a fossil to be created and found.
Now, there is growing use of
DNA to "track back" evolutionary relatives. DNA is being used to determine
how closely related extinct species are to existing ones, or give possible explanations how species evolved.
The other problem is that if the theory of evolution is not a good theory, then what theory is better? As of now, there are none that fit the category of being a scientifically based theory.
The two competing theories are the creationist "God did it" and the intelligent design idea, which is "God did some of it." Both beliefs suffer from theology; both beliefs require the belief in a supernatural being.
If your theory relies on this, to any extent:
then it is not a scientific theory. Scientific hypotheses and theories are testable, whether by the computation of mathematical proofs or by experimentation or by observation. If you are unaware of this, watch a few episodes of the television show
Mythbusters on the Discovery cable channel. It is an excellent basic science show: They take a belief and develop an experiment or series of experiments to test the belief.
The existence of God is not something that can be scientifically tested or proven. The existence of God is a matter of faith. Without having to pull a Willard Romney, if you are unfamiliar with the definition of faith, try this: Faith, in the religious context, is
a belief that is not based on proof. Faith is.
Science is not faith-based. Science is, at its core, based on observation. And when the observable data does not support what the prevailing hypothesis or theory was, then scientists come up with new hypotheses to fit the observations.
That is, in a nutshell, how science works. If your explanation depends, in any way shape or form, on the intervention of a Supernatural Sky-Fucker, it is a religious explanation, it is not a scientific explanation. Such explanations belong in a religious setting, not in a science class.
Whether you like the theory of evolution or not, it has been out there for 170 years and nobody has seriously been able to challenge it with anything other than quibbling or pseudo-religious rantings.
Evolution may not explain everything, but then again, gravity is not fully explained. Those who try to explain how gravity works seem now to have to use terms such as "quantum gravity" or that gravity is a force that acts across many dimensions and may be stronger in other dimensions. But if the concept of gravity is not fully explainable, the observational data shows it is real and if you claim gravity is not real, try walking off a high cliff (but have a camera recording it so everyone can laugh at your demise on YouTube).
If another theory comes along to explain how species arose, scientists will test it and if it fits the facts more precisely, it will be adopted. If you doubt that, see how many astronomers still believe in the "steady state" theory of the Universe.
But until that day comes along, the Theory of Evolution prevails.