Symbiosis is from the Greek for “living together.” A symbiosis is any sort of persistent interaction between two species. Forms of symbiosis include parasitism, which involves a species living off a ...

There are no wild ligers. Indeed, hybrids were once thought to be rare in nature—and of little consequence in an evolutionary sense. But now we know they can play an important role in speciation—the ...

DNA is the genetic code that provides the biological instructions for every living species, but not every bit of DNA helps the species survive. Some pieces of DNA are more like parasites, along for ...