Science can't define species

From EvoWiki

Contents 1 Claim 2 Source 3 Responses 4 Fallacies contained in this claim 5 Further Reading 6 External links 7 Related claims 8 See Also 9 Acknowledgments

Claim

Complaints about creationists not defining "kind" are unfair since evolutionists can't define "species" consistently.

Source

• Evolution Encyclopedia Vol. 1: Species Evolution (about halfway down: "It is difficult to define 'species'..."). Evolution-facts.org. Retrieved on 2008-06-05.
• Jones, Do-While (2002, March). The Species Problem: The Definition Problem. Retrieved on 2008-06-05.

Responses

1. The theory of evolution implies that there is no well-defined barrier which would prevent a breeding population from acquiring arbitrarily many variations from its ancestral stock. Therefore, it follows that if the theory of evolution is true, there should be life-forms which are difficult to classify as belonging to one or another 'species', and it should be difficult to come up with a species-definition which is universally applicable to all life-forms. Since the theory of evolution says it should be difficult to define what a 'species' is, it is not clear why anyone would think that Difficulty In Defining 'Species' is a problem for evolution.
2. Biologists can define specific species, in that, for example, biologists do know what makes a green iguana different from a helmeted iguana. The problem is, no one has yet come up with a species-definition which is universally applicable to all life-forms. For instance, any species definition which is dependent on interfertility is inapplicable to species which reproduce asexually -- and all other species-definitions have their own, analogous, 'holes'.
3. The theory of evolution says that new species arise through the accumulation of changes in a lineage, until the descendants are so different from the original ancestral stock that they constitute a different species (as determined by an appropriate species-definition. If evolution is true, there should be creatures which have only accumulated some of the changes which separate the ancestral and descendant species, and which, therefore, should be hard to classify as being one or the other. Creationism, on the other hand, says that all life-forms fall into one of a number of well-defined "kinds". If Creationism is true, it should be a simple matter to determine the well-defined "kind" for any and all creatures. Since there are, in fact, a number of creature which are difficult to classify, it follows that Creationism is not a good fit to the evidence.
4. "Species" is an arbitrary classification. "Kind" as it is used by creationists, cannot be arbitrary, and must reflect some absolute, divine order, or else it is a Distinction without a difference vis-a-vis "species".
5. The concept of species is a human attempt to classify the differences between organisms over a continuum. The theory of evolution, however, explains why these differences exist. This claim is not a valid criticism of evolution.
6. add more responses

Fallacies contained in this claim

• False Analogy ("species" is a cluster of precise concepts, "kind" is nothing of the sort)
• Tu quoque ("we can't define it, but you can't either!")

Further Reading

• Schilthuizen, M., 2001. Frogs, Flies, and Dandelions: the Making of Species, Oxford U Press.
• Cracraft, Joel, 1987. Species concepts and the ontology of evolution. Biology and Philosophy 2: 329-346.
• Cracraft, Joel, 2000. Species concepts in theoretical and applied biology: A systematic debate with consequences. In Species concepts and phylogenetic theory: A debate, edited by Q. D. Wheeler and R. Meier. New York: Columbia University Press, 3-14.
• Hull, David L., 1997. The ideal species concept - and why we can't get it. In Species: The units of diversity, edited by M. Claridge, H. Dawah and M. Wilson. London: Chapman and Hall, 357-380.
• Kottler, Malcolm J., 1978. Charles Darwin's biological species concept and theory of geographic speciation: the Transmutation Notebooks. Annals of Science 35: 275-297.
• Mayden, R. L., 1997. A hierarchy of species concepts: the denoument in the saga of the species problem. In Species: The units of diversity, edited by M. F. Claridge, H. A. Dawah and M. R. Wilson. London: Chapman and Hall, 381-423.
• Mayden, R. L., 1999. Consilience and a hierarchy of species concepts: advances toward closure on the species puzzle. Journal of Nematology 31(2): 95-116.
• Wilkins, John S., 2003. How to be a chaste species pluralist-realist: The origins of species modes and the Synapomorphic Species Concept. Biology and Philosophy In Press.

External links

• As of June 5, 2008, CreationWiki maintains this claim has no source and that it is not a creationist claim. [1]

Related claims

• Organisms come in discrete kinds
• Range of variation is limited within kinds
• Evolution predicts a continuum of organisms, not discrete kinds
• The Origin of Species does not address speciation

See Also

• Why is Creationism not a Scientific Theory?

Acknowledgments