The evolution of life is one of the most beautiful things I have studied. I am a puzzle fan. I love to put together complex puzzles whether jigsaw, three dimensional, mathematical or geometric. I have had a fascination with puzzles my whole life. When I have trouble putting it together I don't say there has to be a magical step I sit down and try to solve the step or Gap that I'm having trouble with. I have also been a fan of evolution since I first read The Origin of the Species (celebrating it's 150 anniversary this past February) at the age of nine. When you think about the bits of information on life it is not the 2500 pieces of a complex jigsaw puzzle that gets me excited but the billions of facts that we have amassed from almost every field of science by 100's of thousands of scientists from every country in the world. These scientific disciplines include : biology, biochemistry, chemistry, physics, geology, paleontology, archeology, anthropology mathematics, genetics, mathematics and statistics, plus many more. The amazing thing is that these billions of independently arrived at facts all fit together with very few contradictions and these contradictions do not disprove the theory of evolution but just point out holes or as creationist call them gaps. When there are contradictions or gaps this points to areas were research needs to be done.
It is a thing of beauty how nicely this fits together. An example of this is the biologic clock. Scientist have determined the relative rate at which random changes in amino acids lead to substantive genetic changes. Scientist have found that these happen at relatively fixed periods based upon the number of generations. The beauty is that in any two species ( and ten's of thousands of pairs of animals have been looked at) when you look at the number of differences between them and then calculate when they should have a common ancestor it works out to a very high degree of accuracy. This method has been used by scientists to predict what geological layers these common ancestors will be found in and when they look they find the fossils in the right place. This is the most powerful proof of evolution. There are other similar spectacular predictive aspects to evolution and an amazing array of puzzle pieces, literally billions, that fit the puzzle precisely.
Well that Gap was how did Eukariotic(cells with a nucleus) cells develop from prokaryotic(cells without a nucleus) cells. Well in today's Nature researches using two different prokaryotic cells have seen one cell get engulfed by the other forming an endosymbiote or a cell living in harmony within another cell. Over time there is an exchange of genetic material and the engulfed cell becomes the nucleus for the other cell. Also this occurred in an oxygen poor environment. Photosynthesis could not occur until you had eukaryotic cells. This symbiosis led to terraforming of the entire earth to an oxygen rich environment that allowed life as we know it to evolve. In addition this fusion of two cells produced the mitochondria that is present in all eukaryotic cells.
I am sure that the Creationists will find excuses, such as, this happened in a glass dish and there were no glass dishes in the soup that was our early oceans. They may then say that there are now two gaps, one on each side of this finding. The point is that science predicted this result and it fits all of the mountain of data we have and contradicts none. Why would they want a God of the Gaps whose domain keeps getting cut into smaller and smaller pieces. If there is a God isn't it better to envision that that entity created a universe were life can form and not have to do mental gymnastics that try to fit God into gaps we just haven't filled with facts yet.