Sometimes I wonder how much mankind is changing evolution. The process doesn't work in a vaccuum, with each species striving to become the "fittest." No, individuals react to individuals, populations to populations, species to species, ecosystem to ecosystem, etc., man being primary among influential organisms. Global warming the the best example of this, one species changing the global climate that affects many others on the planet, some populations taking it on the chin more than others. Various species, from coral to polar bears are suffering the change we've wrought on the planet, and I have to wonder how life is going to be shaped.
Even though some species die out, life does not entirely disappear, and when new niches open organisms begin to change to take advantage of this. Suburban sprawl has made New Jersey what it is today, greatly reducing suitable habitat for a number of species and decreasing the biodiversity. This isn't to say that life won't continue however, and in fact squirrels, white-tailed deer, black bears, chickadees, and other animals are doing fine. Essentially, they were flexible enough to survive in habitats also inhabited by people, and in some ways humans have even made the habitat more amenable to the animals through keeping lawns and unsecured garbage. In other places, however, some species are dying out or disappearing. Coral reefs or dying or becoming ill, polar bears turning to cannibalism or drowning, birds migrating to Canada lacking food because they miss the explosion of insects, etc. Global warming and habitat loss are putting a lot of pressure on a variety of species, but this isn't to say that all life will disappear. We should try to stop the pollution and conserve what we can, yes, but through our activities and ecological change, different species are being favored more than others. What new varieties of life may someday alive to take over abandoned niches, I'm not sure, but I am certain that mankinds presence on this planet is indeed felt, possibly in some ways we can't even understand yet.
