olemus
Merriam-Webster:
3b: a relation between biological groups involving resemblance in structural plan and indicating a common origin

Wiktionary:
4. the fact of and manner in which something is related to another
7. (taxonomy) resemblances between biological populations, suggesting that they have a common origin, type or stock

ülevaateid
https://en.wikipedia.org/wiki/Affinity_(taxonomy)