Well that's a very long time for animals yes. Bacteria reproduce as fast as every half hour. In that 2000 years, that's 35 million generations of bacteria. You

Well that's a very long time for animals yes. Bacteria reproduce as fast as every half hour. In that 2000 years, that's 35 million generations of bacteria. You can go through a thousand generations in 3 weeks. And every landfill has hundreds of trillions of them. Constantly mutating and competing for resources.