I wish I could convince Marley the Dog that killing lizards in cold blood serves no useful purpose.
Even though the act of lizard-slaying contributes to the balance of nature, I doubt that a hapless, solitary lizards’ demise alters nature’s course much one way or the other.
Marley doesn’t eat the lizard for lunch, nor does the lizard threaten to eat Marley’s next bowl of dog food, so Marley needn’t defend his senseless act of violence on the grounds of self-preservation.
Alas, poor lizard, and alas, poor Marley: natural creatures striving to do the natural. Thankfully, no tigers or lions that might do Marley the same natural violence he did the lizard are on patrol in the back yard.