We’re still discovering new species today. There are probably thousands that we don’t even know about yet. How can we tell for sure if a species has gone extinct?
I've read earlier today that one of snakes just spotted on the coast down there is a slippery nasty disease ridden snake with a head that resembles hillary clinton with stubby fangs and with a herpes type venom!
How can we tell for sure if a species has gone extinct?
Science tells us so.
Taxonomy is such a mess as to have designated individual species for decades that in fact were not. As an example, we have seven "species" of oak trees here on our property, as designated by the "authoritative" Jepson e-Flora. Yet I had a tree geneticist up here recently who declared them all "mutts," and has both the DNA and physical evidence to prove it. In fact, the cross breeding among species was so significant, that even deciduous Quercus kellogii was crossing with Q. parvula shrevii, which is an evergreen tree and still bearing viable progeny! Yet for decades, people have missed noting the symptoms of hybridization simply because they believed they were distinct species when in fact there may only be "red" and "white" oaks.