I almost hijacked an old thread for this, since I'm not sure that it is worth a discussion. But I was pretty jazzed by some news in the latest Economist about the importance of hybridization in speciation. Apparently what was known to occur already among microbes has now been found in, of all places, one of the species of birds included as "Darwin's Finches" in the Galapagos. The phenomenon is that mating between related species occurs, and generates, probably, a new species.
The article has a really good readout from the research that has emerged about hybridization and speciation in complex animals (plants are, apparently, a different kettle of, well, fish) and it isn't clear that the Galapagos example is anything like the original observation. It just makes a good hook. https://www.economist.com/science-and-t ... ary-theory
What caught my eye was the demotion of mutation as a driver for evolution. The original Darwinian formulation, and therefore the textbook version when I was in school, was that the raw material of selection is entirely due to mutation. Probably because I read a lot of Stephen Jay Gould's stuff, who is a skeptic of the mutation-as-driver model, I have long thought it was unrealistically slow. The article gives the example of cichlids in Lake Victoria, which was non-existent as little as 15,000 years ago but now has 500 species of cichlids living within, as evidence that hybridization plays an important role in the radiation of new species within a new niche. Interesting stuff.