Darwin's original tenants of his theory as laid out in his 1859 seminal work, "The Origin of Species," were these: that all organisms evolved from a common ancestor via minor, undirected changes, and that natural selection determines which of those random mutations get passed down to future progeny. Variations that confer a survival advantage allow the creature who inherits it to live long enough to procreate, and pass down that change to the next generation.

Darwin successfully demonstrated "microevolution" with his Galapagos finch study, showing that finches confined to a particular island would evolve differently shaped beaks over time, in accordance with their available food sources. Similar processes have been demonstrated within many other species as well, and few would dispute that such microevolution does, in fact, occur. But Darwin then extrapolated this process, assuming that over the eons, such tiny changes could allow one species to evolve into another. Leaving aside the philosophical objections we've already covered in previous episodes, such as irreducible complexity and information theory negating the possibility of this occurring, is there any evidence that it nevertheless did occur? If it did, the fossil record should be riddled with examples of transitional species--some of which might have been "dead ends," but many of which should have been ancestors halfway between one species and another.

Darwin himself wrote in "The Origin of Species," "Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and gravest objection which can be urged against my theory. The explanation lies, as I believe, in the extreme imperfection of the geological record."  In other words, he figured that in time, and with acceptance of his theory and with scientists all over the globe searching for such evidence, the "missing links" would eventually be found.

So, 164 years later, with belief in evolution dominating almost the entire scientific community, have any fossils of missing links been found?

A quick YouTube search on evolutionary fossils presents the first arthropod, mollusk, insect, etc as "missing links." They're the "first" because of where they were found in the rock strata (where deeper is older). But all of the creatures presented are part of recognizable classes of creatures alive today, though those exact species are often extinct. This means they're the end of a line; they're not an intermediate on the way to anything we can identify. (Some of the species aren't extinct at all though, and the exact same organism is still alive today. This is what evolutionists call "stasis": no change over millions of years.)

The only possible true missing link of which I'm aware is one found in the 1860s, during Darwin's own lifetime, called archaeopteryx. It was a fossil showing characteristics of both a bird and a reptile, and it is the basis of the widely supposed belief that dinosaurs are the ancestors of birds.

Larry Martin, paleontologist from the University of Kansas, said in 1985 that archaeopteryx is not a true transitional species, but merely an extinct type of bird. According to wikipedia, twelve such fossils of archaeopteryx have been found, and all around the same area of Germany, encased in limestone. Since only 12 fossils of this same species were found in a very localized area, Martin's explanation makes the most sense. We should have found many more intermediates all over the world, in various stages of transition, if the hypothesis that dinosaurs were the ancestors of birds was correct. (We also wouldn't have expected the two to coexist either, if one were the ancestor of the other, but apparently according to both the Smithsonian and National Geographic, they did.)

A few other possible contenders for "missing links" have been found over the years, but the case for each of them has been weak at best.

One was the Java Man, found in 1891, supposed to be a missing link between humans and apes. All that was found of it was a skull, a femur, and three teeth. These were later determined to have belonged to three different species.

Another was the Piltdown Ape, found in England in the early 1900s, also speculated to be a missing link between apes and humans. In Nov 1953, however, Time Magazine published collected evidence of multiple paleontologists that this ape too was comprised of fossils from three different species. The BBC later called it "the biggest hoax in British history."

Peking Man was found in China in the 1920s, another supposed c