Does Evolution Imply Progress?
Evolution isn't about progress. It is about species adapting to local environments. If a mutation leads to a member of a species leaving more offspring with this mutation, then the mutation will spread through the local population, whatever the size of "local" is - it might be a few square miles or thousands of square miles - it depends on the species.
An example that evolution is not about progress is the evolutionary history of whales. Their distant ancestors lived in water and certain of their descendants evolved to be land animals - kind of fitting the idea of "progress." However, some of their descendants then evolved back into being water animals, the whales and dolphins - was that progress? A cetacean’s closest living relative, by the way, is the hippopotamus.
Natural selection, one of the mechanisms of evolution, works only on an individual’s adaptability to local conditions and ability to leave more offspring than other members of the local population. If members of one species are isolated into two locales, and it is possible for them to diverge into two separate species over time since they will experience different mutations that give their members better ability to leave offspring. The more different the local environments are, the more rapid the divergence will be.
So evolution is not about progress, it is about whatever change gives an individual and a population the ability to adapt to the environmental conditions it/they experience(s). Based on the data, one must conclude that species develop based on the random mutations they have experienced, and what environmental factors they have been exposed to. Since different species do not experience the same environments nor have the same random mutations, one would not expect different species to develop the same traits to help them survive. It does occasionally occur, and when it does, it is known as convergent evolution.
Science is a fact-based endeavor. It describes what has happened and how it has happened. The theories it develops must explain as broad a range of the facts as possible. Darwin's theory of natural selection and evolution does that. The theory of evolution has allowed the successful prediction of where certain types of species are likely to have existed. An example is the discovery of the tiktaalik fossils. Tiktaalik was an intermediate species between aquatic and land animals that shows an early stage in the development of the wrist. The scientists knew that the trransition between water and land occurred between about 375 and 350 million years ago (mya). They determined where rock of that age was easily reached from the surface based on previous geological surveys. They spent three summers searching before finding it in the region that it was expected. It is an excellent example of the predictive power of evolution.
To summarize, the theory of evolution does not predict progress or the development of any particular characteristic by any particular species. It studies the way species are, what the fossil record shows, and the similarities and differences of the DNA of different species and tries to understand how all the facts tie together.
Natural selection is one of the mechanisms of evolution and predicts only that the characteristics that allow an individual to leave more offspring than other members of its local population, and the accumulated characteristics that allow this population to better survive than other species within its ecological niche are the characteristics that will be selected for. As conditions change, those species that are better able to adapt to the new conditions are the ones that will survive.
