Niddah 51 - One but Not the Other - Wool and Plants
Any time that one has to give a present of wool ( the first of the fleece ) to the Kohen, one also has to give other gifts, that is, foreleg, jaws, and abomasum to the Kohen. However, when one slaughters a cow, he has to give the gifts but there is no fleece.
Every seven year in Israel there is Shmita - no plowing or harvesting (there are different opinions as to whether it applies nowadays). One can collect fruit and vegetables for his own use though, but when there is no more of that species available in the fields, he has to take his supply into the street also, and declare it ownerless, free for all to take. Any species that one is obligated to make ownerless (this is called "removal"), he is also obligated to observe other Shmita laws with, such as not using it for commerce and treating them in a special way. However, mint root, for instance, is always available, because it is underground, so although there are Shmita laws for it, there is no "removal" requirement.
Any fish that has scales certainly has fins, however, there are fish with fins but no scales. Any animal that has horns has split hooves (these are kosher animals), but there are some that have split hooves but not horns - such as a pig.
Art: Antony Troncet - Plowing