Principios de Taxonomia

differences between the sexes can significantly exceed the differences between two
different species (Billeter et al., 2006).
That a human at first spontaneously thinks of different species when he perceives
the different appearance of males and females is proven better by no other than
Linnaeus himself, who at first took the two sexes of the Mallard (Anas platyrhynchos)to
be different species and gave them different names (Mayr, 2000). Linnaeus also
described the immature Goshawk (Accipiter gentiles) as a distinct species because of
its vertically striped belly plumage, as distinguished from the mature Goshawk,
which has horizontally striped belly plumage (Mayr, 2000). Thus, nature has not
shaped species for humans to be able to identify them.
5.7
What are Mutants (in a Taxonomic Sense)?
5.7 What are Mutants (in a Taxonomic Sense)?j103
In addition to races and morphs, there is also an additional intraspecific
morphotype, which, however, in contrast to the race and morph, does not have
any taxonomic importance. It must be considered to be a genetic accident, has
selective disadvantages, and is, thus, usually soon weeded out again. What is
referred to here are the occasionally occurring aberrant mutants, such as, for
example, the albinos, a partly or completely colorless phenotype, resulting from an
inherited dysfunction in the biosynthesis of the melanins. Albinos as genetic
accidents should not be confused with the white morphs occurring in the case of
certain animals, for example, several heron species (see above). These types have
other genetic causes, and obviously play an evolutionary role and should not,
therefore, be considered to be accidents.
The term mutant is defined very broadly in genetics and usually designates any
form of genetic alteration in the genome, from a point mutation up to a chromosome
or genome mutation. For taxonomic classification, by far not all mutants are
important. Only those mutants that produce diagnostically clearly recognizable
phenotypes are relevant. Only such mutants are meant in this context.
Mutant that distinctly alter the phenotypic appearance of an organism have
repeatedly confused taxonomists. Mutants can feign distinct species (Color Plate
7). The spectrum of such mutants ranges from diverging colors and color patterns up
to deformed shapes, such as the so-called mongoloid, a human carrier of Down
syndrome, which results from the presence of three copies of chromosome 21.
Melanism occurs frequently in very different animal species. This phenomenon
refers to abnormal types with dark to black body color, as can, for example, be
observed in the case of various mammals, but also other animals. Melanism is based
on an excessive deposition of melanins. Especially famous are the melanistic mutants
of several species of Felidae (cat-like animals) and especially the case of the Black
Panther, a mutant of the Leopard (Panthera pardus). The genetic cause for melanism
in the case of the Leopard is a single gene that is inherited recessively (O Brien and
Johnson, 2007). Interestingly, Black Panthers occur in different geographical regions
in substantially varying frequencies. Because melanism in the Panther is a recessive