Question

compare Lamarck's and Darwin's theories about organisms change over time.

Answer 1

Lamarck believed that traits were acquired over an organism's lifetime were passed on to offspring; that is, if you were a bodybuilder, your children would have more muscle when they matured. Darwin, on the other hand, stated that evolution takes place over generations and that only genes, not acquired traits, were passed on to young.
As for similarities, they both examined the process of natural selection.