We only have the set of species we were born with. There are not going to be others. (It takes one million to five million years to replace a species, so once they are gone, they are gone. Not just for your lifetime, your children’s lifetime, and their children’s lifetime. Not just your country’s lifetime or our civilization’s.1
(We have already killed off a serious % of species, especially including the prehistoric actions of our species)
We look back on the mammoth, the passenger pigeon, the dodo, and we wonder how our ancestors could have been so cartoonishly selfish as to sacrifice the convenience of the present for the rest of all time. How they were so shortsighted as to steal an entire species from their decedents. But we still don’t see the next impending extinctions in the same light. “It’s just another fish/bird/insect/plant, just like all the rest” is how it feels.
If we can’t conserve a species from extinction, which, I am very aware that we cannot save every species. We can still invest in preserving their genetic code, details on their life history, and everything that will be permanently lost with their disappearance. Future generations will care about what we pass down to them.
About the rate of an island coming into existence? It’s surprisingly hard to find things that happen around once every 5 million years. There is a normal rate of extinction but it’s hard to express because it depends on how many species exist, it varies between groups of species, and we don’t even know how many species exist today let alone millions of years ago to get an accurate rate estimate. Also the background extinction rate fluctuates with things like climate and… you get the idea. Something like one species every 100-1000 years is normal I guess? And right now at least 2 species have gone extinct every year with about 36,000 estimated to go extinct within the next 10 years? So between 2 and 2,000 per year then.