Wednesday, January 9, 2008

What is a Kind?

In previous blogs, I have frequently used the terms “kinds” and “species.” I recognize, though, that many people struggle to understand what is meant by these terms and the difference between them. So in this blog I will spend a little time exploring the meaning of both.

When God created birds, plants, fish, and animals, He told them to reproduce after their kind (Genesis 1:21, et al). This very easily then defines a “kind” as creatures that can (or originally could) reproduce and have fertile offspring. The problem we run into though is that evolutionists tend to define a species in much the same way. So people get the false impression that “kind” is the same as “species.” This then causes a host of other misconceptions (i.e. “speciation means animals can evolve beyond their kind” or “how did Noah fit millions of species on the Ark?”)

But the term species is terribly vague. Wikipedia has the following quotes: “A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring.” So this is similar to the definition of kind. However, Wiki goes on to say, “It is surprisingly difficult to define the word "species" in a way that applies to all naturally occurring organisms, and the debate among biologists about how to define "species" and how to identify actual species is called the species problem.” Many different species, for example, can indeed reproduce and have fertile offspring. For example, coyotes (Canis latrans) can successfully breed with wolves (Canis lupus); why then are they different species? Even though they are different species, they still qualify as being the same kind.

Though it’s relatively easy to define a kind, it’s not as easy to determine to which kind any particular animal might belong. It’s not practical to experiment by cross-breeding every known species. In the case of extinct species, it’s impossible. But for the sake of this blog, we will look at some of the more obvious and common examples.

We’ve already discussed wolves and coyotes, but also domestic dogs, dingoes, jackals, and foxes are interfertile. This would suggest that all dogs species belong to a single canid-kind.

All species of bears within the genus Ursus have been known to successfully interbreed in captivity (polar/grizzly bears are known to have hybridized in the wild). Even the sloth bear (Melursus ursinus) has been bred with the Malayan sun bear (Ursus malayanus) so all bears would seem to be a single ursid-kind.

Horses are an interesting group to study. Evolutionists have often touted that the evolution of the horse is the most complete series yet discovered. Various species within the equid-kind are remarkably diverse. Horses, donkeys, and zebras are known to reproduce (although the offspring are usually infertile). The photo here is of a Zeedonk (zebra/donkey hybrid). I believe the evolutionary series is more likely only various equid species which superficially appear to progress from ancient to complex. Imagine, for example, how various dog breeds could be arranged in seeming progression from the Chihuahua to the Great Dane.

Cats are another well-known example of a kind (felid-kind). It’s long been known that tigers and lions can reproduce (producing both fertile and sterile offspring). We also see leopards and pumas, lions and jaguars, tigers and pumas, etc. There are even several varieties of hybrids between domestic cats and wild cats. The photo here is of a Savannah Cat, a fertile hybrid of a domestic cat and the African wild cat AKA the Serval cat (Leptailurus serval).

The types of hybrids known to exist can be surprising. Domestic cows can breed with yaks and American bison. Cow and bison offspring are fertile forcing scientists to reclassify bison into the same genus as cows. Camels have bred with llamas. False Killer Whales (Pseudorca crassidens) have bred in captivity with Bottlenose Dolphins (Tursiops truncatus) with fertile offspring. While all of these examples have been of mammals, there are also several bird, reptile, and fish hybrids. However, hybridization is most often observed among plants. For the sake of time and space, we won’t explore those here. Hopefully, the examples we’ve already seen will help you understand the much broader meaning of a kind.

An important point must be made. Evolutionists believe that all felid species, for example, are descended from a common ancestor. The irony is that this is exactly the creationists’ concept of a kind. The unidentified common ancestor of the felid-kind would have been on board of Noah’s Ark; then all the various species of cats have descended from this ancestral cat pair (see my blog on speciation).
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There are 2 distinctions between the evolutionists’ position and the creationists’ position: 1) creationists believe speciation occurs more rapidly than evolutionists theorize and 2) creationists understand that variation occurs only within the kind: i.e. all bears species have a common ancestor – the ursid-kind pair on the Ark. On the other hand, evolutionists would have us believe a bear has a common ancestor with a pine tree.

The study of kinds is called Baraminology from the Hebrew words bara (to create) and min (kind). The evolutionary theory has an evolutionary-tree model where all present biodiversity has descended from a single common ancestor. The creation model has a sort of an orchard of trees where each animal was created as a kind, and the wide numbers of species we see today have all descended from a much smaller group of created kinds.
We may never know exactly how many originally created kinds there were. Even so, all the present diversity we see in nature perfectly agrees with the creation account described in Genesis.

3 comments:

  1. " creationists understand that variation occurs only within the kind:"

    Yes - they understand this so well that they feel free to put constraints on their analyses to ensure that they never produce results that do not conform to what they 'understand' so well...

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  2. It's one thing to try and group extant species in "kinds" - but what about extinct ones.

    For example, what kind was Jeholodens in?

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  3. Dankie vir die interessante blog

    ReplyDelete