Sympatric Speciation

We saw that the littlest differences can lead to dramatic variations when we looked at the wide variety in dogs. But despite their differences, all breeds of dogs are still the same species as each other and their ancestor. How do species split? What causes speciation? And what evidence do we have that speciation has ever occurred? Critics of evolution often fall back on the maxim that no one has ever seen one species split into two. While that's clearly a straw man, because most speciation takes far longer than our lifespan to occur, it's also not true. We have seen species split, and we…