Evolution: yes and no?
One reason why life is believed to have originated from a common ancestor is because many species appear very similar to, and therefore related to, many other species. For example, the finch species on the Galapagos Islands are very similar to each other, and since they are close neighbours, it is reasonable to suppose that they all stem from one species that colonised the islands. Nowadays not even creationists dispute that some species evolved from other species. The question is, did all species evolve from a common ancestor, or are there limits to relatedness?
The creation account in Genesis states that God made animals 'according to their kinds'. It does not say that he made them according to the species we see today. We are therefore free to conjecture that a limited number of animals and plants were made with the potential to diversify into many species: all the genetic programming required for them to diversify was built in from the beginning by God. As environments changed, organisms needed to be able to change with them. The evolution of species needed to be part of what God ordained when he commanded them to 'be fruitful and multiply'.
Organisms are very complex, and the biblical view allows us to make sense of that complexity. After creation was finished, all significant biological change was programmed change and was a purely natural process. If we explain life as originating by chance alone we put extraordinary belief in the power of supposed natural 'miracles' which still currently have no clear biological explanation.
The Darwinian view offers a different framework. It seeks to persuade people that the complexity accumulated gradually and accidentally, with each step representing a miraculous combination of mutations along a path extending all the way from bacteria to human beings. Bacteria 'somehow' became eukaryotes. Fish 'somehow' acquired legs and lungs and left the water, and so on. Paradoxically, this atheistic view could be seen as requiring more faith, more willingness to believe, than the biblical view.
Life is a wonderful thing, and any explanation of it cannot but involve belief in miracles, whether at the beginning of creation or all along the way. We prefer the view that does not impute nature with miraculous powers and cannot explain the origin of life. So yes, there has been a lot of evolutionary change over time. But no, the change that is evidenced in the fossil record is not simply the result of chance mutations. Organisms were capable of evolving because they were created with that ability.
A more in-depth look at these issues can be found here.