kitler53 on 20 December 2013
in the higher animals (mammals) there is evidence but not a ton of definitive proof.
but it has been observed in the lower lifeforms which really comes down to time scale. a "generation" for humans is 20 years. for virus/bacteria it can be seconds/minutes so we can observe thousands of generations a year.
...if you've ever gotten a flu shot you (by proxy) believe in evolution. the flu shot is a vaccination which should protect you "forever". ..the reason there is a new shot ever year is the rapid speciation of the flu virus. each flu shot helps protect you from about 10-20 species of the flu virus that medical professions deem most likely to impact you.
