As it turns out, extreme metal fits quite well into the ecological model of adaptive radiation; at least in a general way. First of all, think of a remote island. An island where no blast beats, distortion or tremolo picking has been before. Then imagine the introduction of one original colonists (for argument's sake we'll just use the band Death). No other immigrants make it to this island. The pioneer species, Death, has the entire resource base of the island to fill with its progeny.
What follows is a rapid sequence of speciation and diversification, ultimately filling all the viable niches within the bounds of extreme metal. For example, some members of the population begin to focus their diet on slamming grooves and guttural vocals, eventually distancing themselves to where they no longer interbreed with their source population and become a new species. Others thrive on a diet of speed and relentless blast beats, shrieking their heads off in the forests of the island to become grindcore. And still others might embrace the progressive, noodling aspects of later-era Death and shoot off into the wilds of extreme experimentation. Any number of combinations might be tried, with varying levels of success depending on inter- and intra-specific competition.
Of course, this intense specialization leaves the myriad subgenres vulnerable to extinction because their numbers are low, and the people interested in their music are few as well. While closely allied to other species, they cannot always interbreed to secure new audiences and thus their continuity. The result is a kaleidoscopic array of metal music, some of which may blink out in an evolutionary second, never to be heard from again (Eighteen Visions anyone?). Over a thirty year span we've encountered thrash metal, grindcore, blackened death, melodic death, groove metal, tech death, jazz-fusion, folk metal, djent and on and on.
While you can argue whether Death actually had anything to do with the genesis of Anaal Nathrakh or Russian Circles, etc., I think there is a distinct enough sonic pedigree that has been passed down through the generations, if twisted and morphed and alloyed with other influences, that can be credited to a few pioneer bands. Metal is a very insular genre; it is very much on its own island in terms of popular appeal. The metaphor isn't perfect I know, but at the very least it provides and interesting thought experiment on the evolution of music. A single style exposed to an empty new environment can diffuse across the auditory spectrum until all the possibilities have been exhausted.
Ecology is everywhere man.
Speciation breeds some wild things, no?
