The great contribution of Measuring the Evolution Controversy , says Dr. Niles Eldredge , Curator Emeritus of Paleontology at The American Museum of Natural History in New York, is the rich content of data and analysis that asks detailed questions about the social, economic and political backgrounds of those who tend to reject evolution versus those who accept evolution as science. “The authors — Guillermo Paz-y-Miño-C and Avelina Espinosa — deftly analyze their data drawn from institutions of higher learning in the United States… It is their scientific approach to these issues which makes this book stand out as a uniquely original contribution.”
Darwins theory of natural selection laid the groundwork for modern evolutionary theory, and his experiments and observations showed that the organisms in populations varied from each other, that some of these variations were inherited, and that these differences could be acted on by natural selection. However, he could not explain the source of these variations. Like many of his predecessors, Darwin mistakenly thought that heritable traits were a product of use and disuse, and that features acquired during an organism's lifetime could be passed on to its offspring. He looked for examples, such as large ground feeding birds getting stronger legs through exercise, and weaker wings from not flying until, like the ostrich , they could not fly at all.  This misunderstanding was called the inheritance of acquired characters and was part of the theory of transmutation of species put forward in 1809 by Jean-Baptiste Lamarck . In the late 19th century this theory became known as Lamarckism . Darwin produced an unsuccessful theory he called pangenesis to try to explain how acquired characteristics could be inherited. In the 1880s August Weismann 's experiments indicated that changes from use and disuse could not be inherited, and Lamarckism gradually fell from favor. 
This bears repeating. A theory never becomes a law . In fact, if there was a hierarchy of science, theories would be higher than laws. There is nothing higher, or better, than a theory. Laws describe things, theories explain them. An example will help you to understand this. There's a law of gravity, which is the description of gravity. It basically says that if you let go of something it'll fall. It doesn't say why. Then there's the theory of gravity, which is an attempt to explain why. Actually, Newton's Theory of Gravity did a pretty good job, but Einstein's Theory of Relativity does a better job of explaining it. These explanations are called theories , and will always be theories . They can't be changed into laws , because laws are different things. Laws describe, and theories explain.