This is a change in a DNA sequence that can lead to variation among species. It's like making an accidental typo while typing - sometimes it doesn't matter, but other times it changes the whole meaning!
This is a mechanism of evolution where allele frequencies of a population change over generations due to chance (random sampling). It's like randomly drawing cards from a deck - over time, you might end up with more of one suit purely by chance.
Phylogenetics: This is the study of evolutionary relationships among groups of organisms. Using our analogy, phylogenetics would be like using stopwatches to figure out who ran which race when!