Observed
Natural Selection
The mechanism by which Darwin proposed evolution proceeds, natural selection is a fundamental component of the evolutionary process, and the evidence for its occurrence is too strong for even creationists to deny. The classic example of natural selection at work is that of the peppered moth in pre-industrial England: the population of moths contained both light- and dark-colored ones, but as light-colored moths could camouflage themselves on the bark of birch trees more easily, birds preyed mostly on the darker-colored ones and kept their numbers low compared to the light-colored ones. However, when the Industrial Revolution began, the trees were darkened by smog, and the situation reversed: now the dark-colored moths could hide much more effectively than the light-colored ones. Birds began to prey on light-colored moths much more heavily and the balance of alleles shifted. In a similar example, a multi-year study of the famous "Darwin's finches" of the Galapagos islands demonstrated natural selection at work: In the years following a severe drought, finches with larger, stronger beaks capable of cracking the tougher seeds (which were all that was left) proliferated over less fit varieties.
This is evidence for evolution because: It is one of the essential components of the evolutionary process, a mechanism without which evolution could not possibly work, and it has been observed to work -- and work efficiently -- in nature, consistently pruning out deleterious adaptations and driving species toward higher fitness.
Beneficial, Information-Increasing Mutations
While some creationists will grudgingly admit that a few mutations can produce beneficial effects, they will almost always fall back on their position that even apparently beneficial mutations lose, not gain, genetic information, thus making large-scale evolution over time impossible. However, modern genetics has again soundly rebutted this point by providing numerous examples of mutations that are both beneficial and increase the information of the genome. The most common class of these are duplication and divergence mutations, in which one gene is duplicated and the copy is then free to undergo mutations that cause it to take on a new function while the original function is preserved. Such mutations have been observed producing resistance in bacteria to antibiotics such as vancomycin; there is also evidence that they are responsible for the development of the vertebrate blood clotting cascade and the antifreeze proteins in the blood of polar fish.
This is evidence for evolution because: As mentioned previously, mutations are a key mechanism of evolution, the method of producing new inheritable traits. The fact that mutations that are both beneficial and increase information have been observed means that, in principle, evolution has the ability to produce great diversity and adaptation over time.
Microevolution and Macroevolution
Among the strongest evidence for evolution is that it has been seen to happen, both in the form of variation within populations, called adaptation or microevolution, and in the form of the emergence of new species, called speciation or macroevolution. Speciation, while it is often inferred from the fossil record, has also been observed and documented in currently living creatures. For example, fruit fly breeding experiments have produced reproductively isolated sub-populations under diverse conditions in the lab. Speciation has also been observed to occur in nature, for instance in the case of new reproductively isolated groups of cichlid fishes forming in African lakes after isolation from the parent population.
http://tilapia.unh.edu/WWWPages/malawi/Malawi.html
This is evidence for evolution because: It
is evolution, directly observed. When two populations of the same species are split up and become geographically isolated, there is no gene flow between the two groups. Thus, microevolutionary events (adaptations) that occur in one group will not be spread to the other, and vice versa. Over time, so many of these adaptations may accumulate that the two groups become reproductively isolated -- a point is reached where, even if they were rejoined, they would not be able to interbreed and produce fertile offspring. Macroevolution (speciation) has now occurred. Once reproductive isolation has been achieved, the final step is trivial. Again, adaptations that appear in one population will not spread to the other. Extrapolated over geological time, the result is two entirely separate species that share a common ancestry but bear little or no resemblance to each other. This is the sum total of evolution -- nothing else is required but these small steps, and every step along the way has been directly observed in nature.
Genetic Algorithms
In recent years, a new field in computer science has emerged: so-called "genetic algorithms," which take advantage of the power of evolution to solve extremely difficult problems. They operate just as evolution does -- randomly generating a wide variety of candidate solutions and subjecting them to selective pressure. The losers are destroyed, while the winners move on to the next generation, are randomly mutated and join a new pool of prospective solutions. Incredible as it might seem, this is an extremely effective and very successful way of solving problems that would prove difficult or even impossible for a human designer to overcome. Genetic algorithms have found uses in a wide range of applications: engineering companies are already using them to design wings for the next generation of commercial airliners; pharmaceutical companies are creating new synthetic drugs through a similar technique called "combinatorial chemistry"; geologists use them to predict earthquakes; brokers craft them to pick winning stocks; mathematicians employ them to solve very difficult problems such as the Traveling Salesman's Problem; chemists are just beginning to explore the possibilities of creating room-temperature superconductors or artificial noses that can detect explosives and toxins through a process of artificial evolution. A team of English researchers has used genetic algorithms to evolve a prototype voice-recognition circuit that uses fewer than one-tenth the components of any comparable human effort, an advance that may someday lead to computers that can understand spoken language.
http://www.netscrap.com/netscrap_detail.cfm?scrap_id=73
http://www.lalena.com/ai/tsp/
http://www.accessexcellence.org/AB/BA/combiChem/index.html
This is evidence for evolution because: It demonstrates the power of random variation and selection. The sort of large-scale evolution that brings forth mammals from reptiles or birds from dinosaurs operates only on geologic time scales, too long to be observed directly in a human lifetime. However, genetic algorithms can be used to simulate the process, speeding it up enough for it to be directly observable, and the results are a stunning confirmation of the power of evolution -- effortlessly building highly complex, efficient systems or homing unerringly in on a working solution among millions of candidates.
Verified Predictions
Evolution has been used numerous times to make predictions that were astoundingly confirmed. Charles Darwin himself predicted that, if his theory was true, Precambrian strata must contain fossils, though none were known to exist at the time. Today, those fossils have been found. Darwin also predicted that the ancestors of modern humans would be found in Africa, since that is where our closest extant relatives, the great apes, live; this prediction was of course also confirmed by the eventual discovery of a diverse array of African hominid fossils. Finally, Darwin described an insect-pollinated orchid, the Madagascar Star, with a 30 cm spur and a puddle of nectar at the bottom. Nectar is an adaptation by flowers to reproduce: the sweet liquid attracts animals which rub against the flower in their attempt to get at it, covering themselves with pollen which they subsequently spread. However, if an animal evolved a long proboscis or other drinking organ, it could get the nectar more easily without being covered with pollen. This would spur an evolutionary 'arms race' where the flower's spur continuously grows deeper, while the pollinators' drinking organs continuously grow longer. Based on the length of the orchid's spur, Darwin concluded that Madagascar must have a species of moth with a tongue slightly shorter than 30 cm. Forty years later, a hawkmoth with a 25 cm tongue that fertilized that exact species of orchid was found. One more verified prediction of evolution concerns the discovery of an ancestral ant,
Sphecomyrma freyi, the common ancestor of modern-day ants and wasps, in early Eocene strata -- exactly where experts in ant evolution predicted it would be found.
