Intersexual selection often results in:
Sexual selection, proposed by Darwin in 1871, favors traits increasing mating success rather than survival, via intrasexual competition among same sex and intersexual choice where choosier sex, often females investing more in gametes, selects mates. It explains elaborate ornaments, good genes indicators like MHC diversity and parasite resistance per Hamilton-Zuk hypothesis. Fisherian runaway and handicap principles describe coevolution of preference and trait. Therefore Ornaments describes process enhancing reproductive rather than viability fitness. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype and environment.
Ref: Andersson, Sexual Selection, Princeton, Mate Choice and Good Genes.