The species that includes both SARS-CoV and SARS-CoV-2 is part of the betacoronavirus genus which also includes MERS-CoV and HCoV-HKU1 as well as HCoV-OC43, whi

The species that includes both SARS-CoV and SARS-CoV-2 is part of the betacoronavirus genus which also includes MERS-CoV and HCoV-HKU1 as well as HCoV-OC43, which are different species. They are all part of the coronaviridae family which also includes CoV-229E and HCoV-NL63. Those are the seven we know about that infect humans. Coronaviridae are present in mammals, amphibians and birds, using techniques for protection, infection and replication that work among these, so jumps between them are typical, have happened multiple times and will happen again. For example HCoV-OC43 (humans), BCoV (cows), PHEV (pigs) and CRCoV-2 (dogs) are closely related and likely diverged in the late 19th century, around a time of a major pandemic. Many details of who infected who will probably never be known, because our genetic data from the late 19th century is ... let's say "lacking a few details". Even today data is sparse, to be honest i am surprised we have the technology to gene sequence virae at all, these things are small. Note that the "respiratory syndrome" naming of the species may align well with pictures of intubated intensive care patients and the call to wear masks, but can overshadow relevant details like the vulnerability of the gastrointestinal tract, among other organs, to coronaviridae infection. So a word of warning: be careful when handling bullshit and for fucks sake don't eat undercooked animals.