phylogenetic relation(n = noun.linkdef) affinity - (biology) state of relationship between organisms or groups of organisms resulting in resemblance in structure or structural parts; "in anatomical structure prehistoric man shows close affinity with modern humans"
is a kind of family relationship, kinship, relationship

academic relation, anaphoric relation, attorney-client relation, bank-depositor relation, blood relation, business relation, conditional relation, confidential adviser-advisee relation, conservator-ward relation, director-stockholder relation, doctor-patient relation, executor-heir relation, fiduciary relation, grammatical relation, in relation to, lawyer-client relation, legal relation, linguistic relation, logical relation, magnitude relation, mathematical relation, medical relation, mirror-image relation, nurse-patient relation, part to whole relation, partner relation, personal relation, phylogenetic, political relation, professional relation, quantitative relation, receiver-creditor relation, relation, relation back, semantic relation, sexual relation, social relation, spatial relation, teacher-student relation, temporal relation, trustee-beneficiary relation, whole to part relation