Reproductive Isolation of Kinds vs. Species

“species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups” by Ernst Mayr

This quote, made by Ernst Mayr, functions much better for Kinds than it does for species. It states that species are reproductively isolated from other species. However, in reality what you see is that what we think of as a species can often hybridize with other species, with other genera, and sometimes with other families. Reproductive isolation fits the concept of a Created Kinds much better than it does a species.

A good example of reproductive isolation failing as a definition of species comes with the Goose Family / Anatidae. This family includes ducks, geese, and swans totaling around 400 species. Although species tend to prefer to mate with others of the same species, hybridization does occur both in the wild and in captivity. As would be expected, ducks hybridize easily with other ducks, geese with geese, and swans with swans. However, ducks hybridize with geese and geese hybridize with swans. I will admit, as far as I am aware, there are no recordings of (successful) duck and swan hybrids.

For example, the common Canada Goose, Branta Canadensis, is listed as hybridizing with other geese in the Genera of Alopochen, Anser, Branta, and Chloephaga; with ducks in the Cairina and Anas; and with swans in the Cygnus. This hybridization covers 7 Genera and potentially 4 Sub-Families. This certainly does not sound like reproductive isolation as is commonly described.

Interestingly, a baramin data set study was done on Anatidae. Initial results suggested that the Cygnus / Swans might be a different group, but the resulting multi-dimensional scaling showed a strong tetrahedral shape which is generally thought to show a bias in choosing characteristics that define a group so it was considered inconclusive.

XXXIID. Last Updated: 08/01/2016
Todd Elder

Todd Elder

Todd Elder has a deep desire to understand and experience Creation. As a Baraminologist, his current research includes developing the Katagenos Species Concept, the Natanzera Classification System, and the Floral Formula Method of determining Plant Kinds. As an author and speaker, his books and seminar materials are designed to encourage a growing relationship with the Creator.
Todd Elder

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