>composition I know it's not what you are asking, but... the mitochondria are example of biological composition. They are organisms that (d)evolved to live exc

>composition I know it's not what you are asking, but... the mitochondria are example of biological composition. They are organisms that (d)evolved to live exclusively inside eukaryotic cells, in tight symbiotic relationship. Viral genetic inserts in our genome are another kind of composition. And then there's the gut microbiome, without which we couldn't live off of the diets we do. Nonetheless, the inheritance aspect still is, and will remain, practical and worth taking about; saying "human IS-A mammal" is valid and useful. There may be a hint here, regarding the current trend away from inheritance.