Quite often in a thread about evolution this sort of statement comes up:
"A person will always a person, a rat will always be a rat, bacteria will always be bacteria, a monkey will always be a monkey etc etc"
And my reply is typically to facepalm and try to explain how those are incredibly different changes on incredibly different levels. Now, quickly
enough, I can just provide a simple example. Homo sapiens sapiens.
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: H. sapiens
Subspecies: H. s. sapiens
That's modern humans. Now, let's break it down:
Kingdom: Animalia
We're animals
Phylum: Chordata
We are vertebrates
Class: Mamalia
We're mammals
Order: Primates
We're primates
Family: Hominidae
We're apes
Genus: Homo
We're hominids
Of course, this is all a lot more fun when you have it as a rap featuring Betty White.
So, before you make a statement about change, check what level you're talking about. Are you asking for change at the Genus level? Species? Family?
Phylum?
And now you know, and knowing is half the battle!