Bread-Crumbs Optimization

Someone was telling me that the full text after the "/" in a URL is what ranks for SEO and recommended having it more complete rather the built up with the category key words leading up to it as part of the intended SEO. I am new at this, so forgive my ignorance --- Is there a way to make "clever" bread-crumbs for SEO in something like this? Would this sort of thing be helpful?

Imagine a store which sells lots of fossils and has a category of fossil called shark teeth and this category has a sub category of megalodon teeth which has a sub category of megalodon teeth that are 5 inches.

Level , category name, SEO URL?
level 1: all fossils for sale -
level 2: shark-teeth for sale -
level 3: megalodon teeth for sale -
level 4: 5 inch megalodon teeth for sale -
Optimal Bread-crumbs?
Home ( > Fossils For Sale ( > Megalodon Teeth ( > 5 inch (
Would this sort of hierarchy and bread-crumbs work better for SEO rather than: ??
If this is a good idea, is there a good addon for this?
See attached example