Science in Christian Perspective

Species Concepts and Definitions*
J. FRANK CASSEL
North Dakota State College, Fargo, North Dakota

A group of Christian scientific men, devoting themselves to the task of reviewing, preparing, and distributing information on the authenticity, historicity, and scientific aspects of the Holy Scriptures in order that the faith of many in Jesus Christ may be firmly established.

Reviewing, preparing, and distributing are sometimes hard to separate. Part of our objective, and our purpose in these discussions, is to determine just what the Bible says and just what it allows. Sometimes some of us who are in the scientific fields feel that perhaps the theologians are able to give us better ideas along these lines than we are able to derive for ourselves. 1 think this is part of the reason for our getting together with the ETS periodically.

We also want to know the facts of the created world. We believe that God, who has revealed Himself in various ways, will not be contradictory. Indeed He cannot be contradictory in His various revelations of Himself and hence the facts of science can in no way conflict or contradict the revelations of God by other means, such as in His Word and in Jesus Christ. What we think He reveals in the written Word and what we think He reveals in creation may be different from what is actually there. That is, there is the truth, and then, there is our view of the truth. And this is where the conflicts arise and this is the reason for setting up panels of this nature-discussions-so that we can gain as much of an insight into the facts-find out as many of the facts as possible. There are some things that we just have not found out yet and we want to know the areas in which we lack information. There can be much profitable discussion as to the meaning of the Scriptures or as to what the Scriptures allow. We want to be as informed as possible as to the possibilities and learn

* Edited from a tape of an extemporaneous presentation at the Thirteenth Annual Convention of the American Scientific Affiliation, Ames, Iowa, August, 1958. Introduction to a symposium on What Is a Kind-The Species Problem.

Phylum                  Some Distinctive Characteristics
Protozoa                 Forms self-sufficient in nature as single cells
Porifera                   Body having many pores
Coelenterata           Saclike digestive tract, nematocycts for protection and food getting

Platyhelminthes             flat and soft, often parasitic
Aschelminthes          Body slender, digestive tract complete


Echinodermata          Radial symmetry, tube feet
 
Mollusca                   Limy external shell in most

Annelida                    Body with numerous similar segments, setae
Arthropoda                Chitinous exoskeleton segmented, jointed appendages
 

Chordata                              Notochord, dorsal, hollow nerve chord, gill arches       

as much of God Himself (as He has revealed Himself in His various ways) as we can.

The species problem I think of as being similar to the problems some of us biologists have faced when we speak on science and the Bible. I at least tend to speak more about science and don't say very much about Genesis. People say, "You have told me these things, but you haven't said anything about how this fits in with Genesis." My answer often is, "If you tell me what you think Genesis says, then I can tell you how I think that it fits." There are more views of what the first chapter of Genesis says than there are possibilities of the interpretation of the origin of the organisms that we have today.

This holds also for the species. You can ask, "What is the kind?" "What does the kind mean in Genesis? Does it mean a species?" And we must answer, "You tell me what you mean by species and I'll tell you whether 'kind' means 'species.'" I think as you follow this discussion, you will gather that the biologists who are working in this area in the various fields that we are going to be discussing, and in many that we do not have time to discuss, are not in total agreement as to just what this group is.

What are the biologist's kinds? We have a plant kind and an animal kind. These we call kingdoms. Now we're not even in agreement up in this realm.  Take the little organism Euglena. It has chloroplasts and it is also mobile. Is this a plant or an animal? The botanist teaches that it's a plant, and the  zoologist teaches that it's an animal. There are numbers of organisms that are not as well defined as Euglena. Many of us have been taught that there are two kingdoms-the plant kingdom and the animal  kingdom. Some taxonomists-people who work at  classifying organisms-say that to classify simply as "plant" and "animal" is not satisfactory. Some suggest as many as six kingdoms now. In the kingdom Protista, for instance, some include viruses, bacteria, protozoa, and algae. There isn't total agreement, then, as to how many major categories or groups there should be, nor as the categories into which some organisms fall.

Classification is based (as we will emphasize


Common Name                                                        Representative Forms
Protozoans                                                                Amoeba, paramecium, euglena
Sponges                                                                    Bath sponge
Coelenterates                                                           Hydra, jellyfish, coral
Flatworms                                                                 Planaria, liver fluke, tapeworm  
Roundworms and others                                          Rotifers, hookworm, trichina worm
Echinoderms                                                             Starfish, sea urchin
Mollusks                                                                   Clam, snail, octopus
Segmented worms                                                     Earthworm, leech
joint-footed animals                                                  Crayfish, lobster, insect, spider
Chordates                                                                  Fish, reptile, bird, mammal, man

later) on degree of similarity and degree of difference. Animals are grouped according to their similarities; they are divided according to their differences. We shall be discussing the animal kingdom for the most part because it is the one on which the panel members are best informed. It is divided into "kinds" wfiich are known as phyla, the major ones of which are listed at bottom of preceding page.

The phyla are divided into "kinds," groups called classes. The classes of the Chordata, for instance, include cartilaginous fishes, bony fishes, amphibians, reptiles, birds, mammals. Each of these may be divided still further into groups (kinds) known as orders, the order into families, the family into genera, and the genus into species. Each kind is grouped with others of its kind because of similarity and separated from other kinds by differences. To illustrate, a robin is classified as follows:

It 'is the classification category level of Species which we will he discussing. When considered in the above relationship, the category of Species may seem rather clear-cut. May we examine it more closely? just what is a species? Since this category is considered the basic unit of classification, we have to understand what it it is before we can understand fully any of the other categories. And we must understand the nature of each category before we can determine its relationship to the use of the word in in Genesis. That the idea of species is not clear-cut is demonstrated by the fact that at its annual meeting in 1955, the American Association for the Advancement of Science sponsored a symposium on "The Species Problem." This symposium was under the chairmanship (and editorship) of Ernst Mayr (Publ. 50, A.A.A.S., Washington, 1957). Most of our remarks will be based upon this symposium as being representative of views now held by people working in this field and concerned with the problem of the species.

In his introduction Mayr points out that several approaches have been used in defining species. One is like that mentioned above which has to do with a group of animals that are very similar in their structure. It is known as a "Typological-Morphological Species Concept" (p. 11-14). According to this view all animals having certain characteristics (usually as represented by certain specimens, "type specimens," on file in a designated museum) constitute a certain species. This can be quite restrictive. Sometimes from a single specimen, or a very small series, a taxonomist will describe a new species, designating one specimen as his "type"-that is, as representing his best concept of the characteristics of the species he is describing. The next worker then has to determine whether what he has is enough like the first man's description or type to be the same thing or whether it is different enough to give it another name. This is taxonomy in action. Do we need another name or can we use the same name? Upon what basis shall the decision be made? How much alike are the specimens in question? How do they differ? How much do they differ? After considering the data amassed from such inquiries, the investigator then must decide whether the later form can be grouped with the former according to the restrictions of the description. If not, he will probably go through the same process to describe and name his form, so that future investigators will have a name to use in discussing this kind of organism. This is one aspect of a species, organisms that are like certain other organisms previously described and named.

There is another aspect of species which Mayr points out. When you see or hear the word "robin," you get a mental picture of a robin. You may think of robins in your back yard, of robins flying around Ames, or wherever else you've seen them. You get a certain idea of Robin as a group of animals actually living in nature. I want to designate this as a "Conceptual View" (p. 14-16). (Mayr gives it no name, actually.) What is your idea? It is not based upon a type, an actual organism, but on what you think of when the name comes to mind.- This "definition" is somewhat broader in its limits than the typological one.

The third definition, one emphasized by Mayr and others in the symposium, is called the "Biological Species Concept" (p. 16-19). This view pays attention to how a group of animals come to be, to how it is maintained, and to what it will be in the future, as well as to what it actually looks like now. It presents the species as being a group of animals or plants which are interchanging their genes. The form of animals or plants is determined by structures within the nucleus of the cell known as chromosomes. In these chromosomes are genes-the hereditary factors. These factors, to be effective upon the offspring of any mating, must be passed on to that offspring. The particular combination of genes occurring in the offspring determine its form. Its actual structure-what the animals look like-is perpetuated by the passing on of these genetic characteristics from one generation to another. This passing on of characteristics is very important in the concept of the species. If there is going to be any change in the species it must come through a change in the genetic make-up of the organisms which are further produced. This is the reason there is a great deal of emphasis being given to this particular concept at the present time. If all organisms, all the various different ones, have indeed evolved from ancestors in time past-then this is the only known mechanism whereby such differentiation could have been accomplished.

Buthow much change-how much differentiation is possible? Are there any limits to this process? If so, what might they be? As we discuss this matter of organisms containing hereditary characteristics which they pass on ~to their offspring, we are discussing, as many authors have pointed out, "evolution in action." Evolution is defined by some as any change in plants or animals which can be passed on to their offspring. By this definition any inheritable change is a form of evolution. Such change would tend in some cases perhaps to develop new species.

We want also to examine "creation in action." One of the points that we need to consider is, "Was God's creative activity greater at one time or another?" Is it true, as Carl Henry ("Science and Religion" in Contemporary Evangelical Thought, New York: Harper, 1957) says in one of his recent books, 

that one of the essential criteria of creationism is "that God created ex nihilo by divine fiat." Or, if I may put it this way, magical development-the appearance of a form where there was none before. This is considered by some, as I say, to be a necessary postulate of creationism. Is it?

These are some of the things, then, that we want to explore-that we want to consider-as we look at this problem of "What is a species?" How does it apply to, "kind," as the word is used in Genesis, in particular, as well as elsewhere in the Bible? Several papers have been presented on this subject in past conventions. Today, as I said before, Dr. Marsh will read his paper on "Genesis Kinds in Our Modern World," which we have characterized as a conservative creationist viewpoint of this problem, and then the other panel members will suggest some of the viewpoints that have been brought out either in the A.A.A.S. symposium or in other realms. They are by no means restricted to the symposium. We use this as a basis because it gives an excellent summary of what present-day scientists are thinking along this line. Then we'll have further discussion.

REFERENCES

Henry, Carl F. H. "Science and Religion" in Contemporary Evangelical Thought. New York, Harper, 1957. (See also his "Science and the Bible," 1958, Christianity Today II [23]:20-22.)

Mayr, Ernst. "Species Concepts and Definitions in the Species Problem." Publication No. 50 of the American Association for the Advancement of Science, Washington, D.C., 1957.