The majority of hybrids are fertile. Lions and tigers, zebras and horses, etc etc can all produce fertile offspring. Fully sterile hybrids are not the norm. Further, there are ring species (https://en.wikipedia.org/wiki/Ring_species). How does that fit your definition. Then your definition fails to account for asexual reproduction.
Even a purely genetic percentage similarity definition of species fails in real life for many cases. You can have species that are super similar genetically but differ substantially in behavior and morphology. Or species that are very similar biologically but differ hugely in genetic similarity (wild type e. coli and laboratory e. coli only share 50% of their genetic code).
Even a purely genetic percentage similarity definition of species fails in real life for many cases. You can have species that are super similar genetically but differ substantially in behavior and morphology. Or species that are very similar biologically but differ hugely in genetic similarity (wild type e. coli and laboratory e. coli only share 50% of their genetic code).