I don’t think anybody believes in the theory of the accumulation of many individually small mutations leading eventually to new species. That was the theory I was taught back in grammar, nearly 60 years ago. The current theory is called “punctuated equilibrium, and sounds like a miracle theory of the diversity of life. The “tree” of life has been replaced by a “bush.”
Umm. Okay.
What is actually observed is just that, but turned upside down.
Dogs, cats, bovine, primate, amphibs, etc.
Then, variation based in isolated populations and beneficial traits becoming common.
Think rabbits. Varying hares etc.
Look at dogs, man manipulates/isolates if you will, for wanted traits. They become “breeds”. But all dogs. They can reproduced across all breeds. All dogs.
The evolution theme is just an unreasoned attempt at denying a creator and replacing Him with time, making man just an animal. Its a religion.