Here's an experts opinon that explains it better than anything I could do.Let's talk about this cancer thing. This question doesn't really matter to the subject but I'm going to ask it anyway. So cancer is mutation, but is it random mutation?
Are there not "causes" for cancer?
Its a couple separate things, you can be the healthiest person ever and still get cancer, because of a defect in tumor suppressor genes (a mutation). You can also get cancer from carcinogens which essentially destroy cells, prompting more cell replication, prompting more chances for a defect in tumor suppressor genes.
Yes we know mutation can kill you but the trick for evolutionists is being able to show how random mutation creates a new attribute that leads to a new species.
Does natural selection lead to new species, and if so, how?
Futuyma: It sometimes does but not always. A great deal of evolution by natural selection can happen without the formation of new species. Natural selection is only the process of adaptation within species, and we see many examples of that. Under some circumstances natural selection does play a role in the origin of new species, by which I mean a splitting of one species lineage into two different lineages that do not interbreed with one another — for example, the splitting of one ancestral primate lineage into one that became today’s chimpanzee and the other that became the hominid line resulting in our own species. The process of splitting and becoming reproductively isolated, that is, incapable of breeding with one another, can often involve natural selection but perhaps not always.
In one scenario of what needs to happen to form a new species, is an isolation of two lineage's of a species, so that they no longer can and/or will procreate... this explains why birds in northern South America and the Galapagos Islands share a very close common ancestor, but are not the same species... because at one time they were the same species, and environmental isolation caused by the separation of the island from the continent (also a proven scientific theory, not pseudoscience), separated them.