Well yes, and we already have engineered bacteria in use for breaking up oil spills at sea.
But evolution amongst viruses, prokaryotes and archaea is VERY different to that in eukaryotic life, due to the sheer speed of replication, allowing many many countless hordes of generations to be iterated through in the time it takes a single multicellular life to run from birth to death. Especially amongst viruses with their (for the most part, not talking about those giant viruses that infest amoebae like megavirus, mimivirus and co. (they really are fucking HUGE, one of them is over a micrometer in diameter iirc, big enough to be visualized under a high powered optical microscope, which for a virus, whos size is usually measured in the multiple tens to a couple of hundred nanometers, is way beyond morbidly obese, so to speak but as far as I know the analogy still holds, afaik they still hijack the RNA/DNA polymerases and transcriptases of the host for their own end, and they are still both parasitic and lethal to the host. But those things are SO different to conventional viruses and viroids (viroids are replication deficient, stripped-down viruses possibly, or potentially genetic leftover survivors from a pre-DNA 'RNA-world' before DNA and proteins evolved, or even possibly, before the first proto-cellular life making them almost-abiological, hovering right on the borderline between life and non-life, long strands of parasitic cyclic genetic material, kind of 'parasitic plasmid'-like, almost in that sense that they undergo rolling circular replication like a plasmid, although some viroids can selfreplicate via ribozyme-type activity [a ribozyme is a length of RNA capable of acting upon itself in an autocatalytic manner, like a self-targeting enzyme, catalyzing its own replication], most of them aren't human pathogens, but affect primarily, plants, with the notable exception of hepatitis D, which may not be a typical viroid, and be a true devolved virus, if the pre-biogenesis hypothesis is true of viroids sensu stricto. Hep-D requires coinfection with another hepatitis virus to cause an infection, without coinfecting the same cell as its required viral partner it can't hijack some of its needed co-factors by way of replication enzymes. I guess you could almost call it a viral infection of viruses, in a loose manner of speaking.
I find the ORIGINS of life far, far more interesting than the extinction of it. THATs easy enough to achieve by any number of natural means, and truth told its a bit of a misnomer to speak of 'the' extinction of the dinosaurs, there were several mass extinction events. And presumably with different causes, such as in one case at least, oxygen enrichment reaching levels in the atmosphere the organisms present already could no longer tolerate. More or less, they choked to death on their own shit. Which we now enjoy continually breathing. What a delightful thought.
The big event at the end of the cretaceous era that massacred most or all the dinosaurs is pretty much certain to be an impact event, and by a BIG bastard, one that would probably wipe our, and most other species out, the size of a reasonable-sized landmass, like a US state. Not quite sure HOW big of a blast that would result in, but you'd want to stick your fingers in your ears, and quite possibly someone else's fingers too thats for sure. Bigger than anything we have the current capacity to create by orders of magnitude anyway. The reason its more or less certain to be an impact from space, is the K-T boundary, a widespread layer of iridium, along with things that require massive forces to create, that are usually found at ground zero of a nuclear explosion, or after impacts like whatever the hell it actually was that fell down on Tunguska, siberia. Ir is very rare on earth. Well, no more so afaik than it is elsewhere in space, only its inaccessible, along with most of the content of other really, really heavy, dense elements like osmium and iridium, some of the other platinum group metals, they were dense enough to sink down to the earths core, especially as they are somewhat often associated with iron geologically speaking. So they were, so to speak, dragged down to hell with it, when that iron formed the earths core. And as well as the iridium (in some places the relative abundance of the element is over a hundred times the quantity found elsewhere in most of the world. It is, though, common in meteorites, as there it never has had a chance to sink down to a planet's molten core while sitting around floating through space.) there are also rich deposits of tiny beads of melted glass, which must have been created during the impact, some but not all, thrown up high into the air, to be redistributed around the planet.
Fuck I bet that thing went off with one hell of a bang (hey, at least, y'all can give me and lit both the benefit of the doubt on that one!) Think I'm paying for a chemical order that large oonly to blow it all to hades? not with so many other interesting natural phenomena there are to intrigue me. Stuff like shooting conkers out of trees with improvised artillery was fun all right, but someone could do a lot worse with for instance an EMP, if they were that way inclined, and its possible to turn chemical energy into EMP output by using timed explosive shaped charges to compress a thin metal coil in such a way that a massive capacitative load from something like a spark gap voltage increase circuit like a mark generator, or maybe cockroft-walton, that it the shaped charge shorts the wire, while the pulse is still contained within the coil section of the pulse circuit, the result is a brief, fairly wideband iirc and high amplitude EMP. its called an explosively pumped magnetic flux compression generator. Never built one, but the output can be big, would make a hell of a mess by virtue of modern dependence upon technology. The correct situation in which such an EMP took place and it might even turn out worse, at least in a non-tribal type of society. Or something like a virtual cathode oscillator, some vacuum knowhow and glass fabrication needed, but microwave output up to a terawatt, in brief or possibly chirped pulses, depending on your available power supply and the depth of your pockets or ability to fabricate large cap banks, do what you like with it, so to speak. Although I wouldn't recommend TV dinners...
Something tells me rated that high its going to be a one shot event, and the grid would burn out the moment the load is put through, unless its extremely brief.