Dramatic frequency change of an allele at a single Mendelian locus in 100 years. Kettlewell placed the different colored moths on tree trunks of different background color and showed that bird predation was higher on the more visible form. Either the variant was there and it was swept to high frequency or recurrent mutations arose that happened to be resistant. Microevolution and macroevolution . The fact of evolution can be documented at either of these two dramatically different time scales.
Embryos look alike while adults look different.
Artificial selection Dogs all descended from Wolf-like ancestor, selectively bred to have different traits.