We always think of natural selection as occurring at the level of populations not individuals. how about century old trees where germline is being produced from constantly dividing cells. Are all meristems in an old tree sharing the same genetic material, or enough mutations occur that different meristems have a different genetic background and are being selected differentially? Do different cells in a tree behave evolutionary more like different populations?
Added Note: The point I was trying to make is that for multicellular organisms in which the germline/somatic separation does not occur early in life, maybe Lamarck was not that wrong. In school we always learn to ridicule Lamarck with the giraffe story. But maybe in some instances Lamarckism makes at least as much sense as Darwinism.