Most species were but are no more. Wiped out by vengeful gods or done in by inescapable facts. Knocked off by the competition, messed up by new world orders human and otherwise.
Most of the gone do not even live on in memory, but a few do. Dodos waddle through our lore trying to wag cautionary tails, but fail. Passenger pigeons do a little better, but their ghosts still topple out of the sky every time the enormity of their genocide occurs to them.
We build dinosaur shrines in the world's great museums, more comfortable because we cannot be held responsible in their case. It's nice to believe that the forces that brought down these megafauna were maybe just culling the ungodly, that this kind of thing happened way before people walked the earth. Just how long before? Too many people have no clue, and I've met plenty who are unconvinced that humans and live dinosaurs don't overlap.
Such people are among those who remain unconvinced as well that there are any problems with human expansion, our appetites and wastes, and our vast creativity with chemicals and machines (unfortunately paired with a similarly vast disregard for the future of any other species). Much of the worst we apes have done has required that we burn the fossils of many species that if not extinct, have been dead for millions of years. A mass cremation of dead and buried plants and animals. A desecration? I've never heard people put it that way, but if it were my grandparents, I don't want them used for fuel.
Maybe I am not human enough, maybe I lack good old American invincibility. The kind that says we're the best breed, uniquely suited to rule the globe, unlikely to succumb like every other empire before us. When we are sure we cannot ever become extinct, that God chose us or we have a unique brain that will figure a way out of any jam, we're free do whatever we want, regardless of the cost.
Like extinction of other species. We are now in the midst of a mass extinction so large that it will go down in geological history. People can argue, suddenly turn all scientific and demand to see solid unassailable proof, but really there's no denying that humans are partly to blame for the Holocene's (Anthropocene, if you're not orthodox) wave of extinctions. We may eat an entire species out of existence, or cut down its forest, cut off its river, fill up its swamp, take out its habitat. We may dump poop or dioxin until a place becomes unlivable, or pump the air so full of cow farts and smoke that we alter the ocean, atmosphere and climate.
Many species become collateral damage in our campaign to cover the earth, but by and large we humans could care less. And we don't think it will ever happen to us. We humans can be cruel gods.