We speak of an analogy when one structure is similar to another or has the same function, but whose embryonic development and its origin or ancestor is not common, they are different, in other words, they are analogous structures if they fulfill functions or acquire similar characteristics starting from the same medium, without requiring them to have the same evolutionary origin (they may or may not be similar structurally and embryologically).
Fitness is the survival or reproductive rate in which a genotype or phenotype have the ability to reproduce more successfully or leave offsprings relative to other genotypes or phenotypes. It is the quantitative representation of natural or sexual selection. It is represented by w.
