Most people would agree that the climate crisis is real and serious. Many people would say that we are not doing much to combat it, and they are probably correct.
One effect of the climate crisis and the spread of humanity to all corners of the globe is that species are becoming extinct, as climate change or the spread of humans and their activities destroys their habitats. In some cases, humans have deliberately targeted species for food or even sport. If you search the Internet you will find numerous lists of extinct species like this one.
Unless these animals, and others who have lost their habitats from climate change, or human expansion, can find new ways to hunt, then they are doomed to extinction.
Humans are expanding so fast, and taking over so much land, that they are destroying the habitats of species and driving them to extinction. Logging and forest fires, both natural and deliberately lit, have decimated the habitat of the orangutan , for example, and many, many other less noticeable species have probably already been driven to extinction .
As I have said, the coming apocalypse is probably unavoidable. Many species will become extinct, and the human race, at best, will be reduced almost to the caveman level. At worst, we will become extinct too. Post-apocalyptic novels generally show the human race bouncing back from almost complete annihilation, but that is unlikely to happen. Species don’t often rebound from such a set back if their habitat has been destroyed.
Suppose the human race and 90% of life on Earth becomes extinct. What then? Well, actually, the outlook is bright for the planet. This is not the first time that such an extinction event has occurred. According to some, there have been five prior mass extinction events.
So, life on Earth, as a whole, has bounced back, even if individual species, have been rendered extinct. How does this happen? Surely there would be fewer species around, and while competition might be reduced and predators may have become extinct, still, how are a few species going to repopulate the world?
It may be surprising to some, but almost all of the species that have ever existed are now extinct. Every species that we see is a descendent of a few species that survived the previous extinction event. Only about 25% of species that existed at the time survived, and in earlier extinctions, only 5% of species survived.
Suppose one species, maybe a badger, survives. Whatever species (plural) survive, they are likely to be adaptable, able to eat anything, and be fast breeding. The badger flourishes in the post-apocalyptic world, and spreads far and wide. Few other mammals are around to compete with it.
The badger families start to differentiate. Some prefer open areas, some prefer trees, some might even take to the water. Over a long period the families lose the ability to inter-breed. They become different species, filling all the niches that other species used to fill, and they don’t even look like badgers any more.
If this is a sixth extinction event then for a long time only a few species would rule the world. But over a longer time frame, as I noted above, the few species would evolve to fill all available niches.
DNA, which is within every living thing, determines everything about an organism. Species, shape, abilities. DNA is so flexible that the number of possible organisms is very large, almost infinite. This means that even though millions of species may become extinct, the few survivors can evolve into millions of new but different species.
So, while there would not be mice, there might be mouse-like creatures. There would be bird-like creatures, mosquito-like creatures, and probably human-type creatures. They wouldn’t look much like their present day counterparts, but they would fill those niches, provided those niches still exist. As an example the replacement for the bird species would probably be as different from birds as the pterodons were from present bird species.
It depends on what the conditions turn out to be. For example, in the time of the dinosaurs, the Jurassic and Cretaceous periods, conditions favoured large herbivorous animals, although there were certainly also large carnivorous animals.
But those were only the most obvious species. I avoid the word ‘dominant’ because they may have been the most obvious, the biggest animals, but there may have been smaller, less obvious animals that we know little about. (I may be showing my ignorance here!)
Intelligence has, so far as we know, only evolved once. It may well be a fluke, and in the future, post-apocalyptic world, it may not evolve again. If it does, let’s hope that any intelligent species that evolves in the future will do better than we did.