Predictive power
A central tenet in science is that a scientific theory is supposed to have predictive power, and verification of predictions are seen as an important and necessary support for the theory. The theory of evolution has provided such predictions. Four examples are:
* Genetic information must be transmitted in a molecular way that will be almost exact but permit slight changes. Since this prediction was made, biologists have discovered the existence of DNA, which has a mutation rate of roughly 10−9 per nucleotide per cell division; this provides just such a mechanism.[26]
* Some DNA sequences are shared by very different organisms. It has been predicted by the theory of evolution that the differences in such DNA sequences between two organisms should roughly resemble both the biological difference between them according to their anatomy and the time that had passed since these two organisms have separated in the course of evolution, as seen in fossil evidence. The rate of accumulating such changes should be low for some sequences, namely those that code for critical RNA or proteins, and high for others that code for less critical RNA or proteins; but for every specific sequence, the rate of change should be roughly constant over time. These results have been experimentally confirmed. Two examples are DNA sequences coding for rRNA, which is highly conserved, and DNA sequences coding for fibrinopeptides (amino acid chains that are discarded during the formation of fibrin), which are highly non-conserved.[26]
* Prior to 2004, paleontologists had found fossils of amphibians with necks, ears, and four legs, in rock no older than 365 million years old. In rocks more than 385 million years old they could only find fish, without these amphibian characteristics. Evolutionary theory predicted that since amphibians evolved from fish, an intermediate form should be found in rock dated between 365 and 385 million years ago. Such an intermediate form should have many fish-like characteristics, conserved from 385 million years ago or more, but also have many amphibian characteristics as well. In 2004, an expedition to islands in the Canadian arctic searching specifically for this fossil form in rocks that were 375 million years old discovered fossils of Tiktaalik.[27]
* Evolutionary theory predicts that novel inventions can arise, while creationists predict that new "information" cannot arise, and that the Second Law of Thermodynamics only allows for "information" to be lost.[28] In an ongoing experiment, Richard Lenski observed that E. coli evolved the ability to metabolize citrate, which constitutes a novel invention, and an increase in the information of the DNA of the E. coli.
