“Hybrid”
describes the offspring of two different species. Some people use
reproductive tests to identify species. Thus polar bears (Ursus
maritimus)
are a different species than grizzly bears (Ursus
arctos horribilis)
because they don't normally reproduce together in the wild. However,
we have discovered that, on rare occasions, these
species have bred in the wild producing hybrid cubs. The
offspring of such unions are called a “pizzly” if the father were
a polar bear and a “grolar bear” if the father were a grizzly.
Either way, the simple fact that these different species do
occasionally hybridize in the wild undermines the use of a
reproductive test to identify a species.
I've
always favored using morphology to identify a species. Once a
population has enough traits in common that they can all be
identified as belonging to the same group, then they earn the moniker
of species. Thus bears with large bodies, white fur, long necks, and
pointed faces are “polar bears”; bears with smaller bodies, brown
fur, short necks, and flat faces are “grizzly bears.” Admittedly
that definition has it's own difficulties but at least it
acknowledges the fact that identifying a species is more subjective
than objective. It also dispels the mistaken impression that species
are absolutely distinct and don't reproduce together.
The
term “hybrid” is a sort of misnomer and gives a false impression
of the importance of reproduction between different species.
Hybridization is so common that I'm surprised that a reproductive
test is even considered as a possible way to distinguish one species
from another. The reproductive boundaries are crossed frequently in
the wild and are absurdly common in captivity. Let's look at a few
of the more interesting ones.
We've
already talked about pizzly/grolar bear hybrids but there have been
many crossovers between other bear “species” (usually in zoos): a
Malayan Sun bear and a sloth bear, a sloth bear and an Asiatic black
bear, a black bear and a spectacled bear, and a black bear and a sun
bear.
Cat
hybrids are fairly well known but the number of combinations is still
remarkable. Lions + tigers is especially common; the offspring are
called either ligers (lion fathers) or tigons (tiger fathers). Other
examples among the Panthera
genus include lion/leopard hybrids, lion/jaguars, tiger/jaguars,
tiger/leopards, and jaguar/leopard. The features exhibited among the
cubs of these unions sometimes blend the parents' features so well
they appear to be Photoshopped together.
Horse
and donkeys have been bred for centuries to produce mules. However,
in spite of their differing chromosomes, horses call also reproduce
with zebras (zorse) and zebras can breed with donkeys (zeedonks).
The offspring of these combinations are almost always sterile.
Domestic
cows can breed with buffalo (beefalo).
Camels can breed with llamas
(camas).
Wolves can breed with domestic dogs (wolf dogs) and with
coyotes (coywolves).
Besides
mammal species, fish also hybridize. A while back, I blogged about
hybrids
between the Australian black-tip shark and the common black tip
shark. Scientists called that “evolution in action” but I
won't go into that now. It again represents the fact that the
boundaries between species is not a reproductive one. Hybridization
also occurs among birds, insects, and especially plants. Again,
there are far more examples than I can begin to address in a single
blog post.
Speciation
and hybrization are especially relevant to an understanding of
creation. The Bible says that God created animals “according to
their kind” (Genesis 1). When Noah entered the Ark, he had
“kinds” of animals on board with him. There are millions of
known species and perhaps millions more undiscovered. However, the
vast majority of these millions include bacteria, plants, algae,
fungi, and insects. Noah did not have to make accommodations for any
of these (though many probably did make their way on the Ark).
According
to Wikipedia,
there are only about 62,305 species of vertebrate animals. About ½
of these are fish and another 10% are amphibians. Noah did not have
to provide for these either. That leaves less than 25K vertebrate species
Noah had to concern himself with (never mind that some of the mammals
and reptiles are also marine dwelling). So, does this mean that Noah
had to take 50K animals on the Ark (a male and female of each
species)? Hardly. We've already seen that “species” aren't
distinct. There are eight species of bears but Noah did not have 16
bears on the Ark; he had 2. There are 41 cat species but Noah did
not have 82 cats on the Ark; he had 2. Ditto for the many species of
dogs, cattle, squirrels, deer, parrots, ducks, etc.
I've
heard varying estimates of the number of animals Noah would have had
to have on the Ark in order account for the number of species we have
today. Some estimates are as low as 3,000 while others range as high
as 15,000. Even the highest estimates are far less than the
“millions of animals” caricature used by evolutionists to
criticize the Flood event.
“Species”
is a label we use for convenience. Though I sometimes chide
evolutionists about it, I really don't have a problem with the term;
I only object to the idea that when populations specieate that they
have somehow “evolved.” The ancestral kinds on the Ark were
necessarily genetically diverse. The descendants of the original
Ark-kinds (cats for example) have adapted to their various ecological
niches around the world. The resulting populations are called
“species” (lions, tigers, lynxes, ocelots, cheetahs, etc). Each
one possesses different combinations of features already present in
the original kind. When the different species hybridize, they merely
recombine the same features in new ways. We could potentially get
new species but we won't get new kinds.
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