The descendants of an X (cat, dog...) will remain X
From EvoWiki
Contents |
Claim
No matter how many generations there are, a cat will always give birth to a cat, and a dog to a dog, and a fruit fly to a fruit fly.
Source
- Anon, 1985. Life--How Did It Get Here? By Evolution or By Creation? Watchtower Bible and Tract Society of New York, Inc., p. 23
Responses
- This claim is actually correct: what is mistaken is the belief that this contradicts what evolution or common descent suggest happen over time. This claim rests on a misunderstanding of how cladistic taxonomy works.
- First of all, the basic structure of the claim is akin to arguing that all the descendants of mammals are "still" mammals. While this claim is true, note that it does not say anything against the idea that ancient shrew-like mammals could evolve into varied species like dogs, cats, elephants and so on. All of these varied species are still rightly grouped together as mammals. Likewise, all mammals are themselves "still" vertebrates, even though modern vertebrates are very different from each other.
- In just the same way, while all the descendants of, say, fruit flies will all rightly be called fruit flies, this does not preclude them from speciating or changing, even radically. What matters to biological classifications is their common origin: no matter how much the descendant of a fruit fly might change from its parent species, it will always be more like all other fruit flies than it will be like any other form of life and hence will be classified as a fruit fly (even if it is a new species of fruit fly).
- The claim assumes that species are what mathematicians call an equivalence relation. That would mean that if A and B belong to the same species (can interbreed), and B and C belong to the same species, A and C do too. But there are heaps of evidence against that, starting with ring species.
- Neither cats, nor dogs, nor fruit flies are individual species. If this statement is made about any individual species, it is false. However, feliformes will always give birth to feliformes, caniformes will always give birth to caniformes, and so on. All descendants of a member of a clade are also in the same clade.
- add more responses
Fallacies contained in this claim
- Straw Man (inaccurate model of cladistics)
- Equivocation (ambiguously used terms)
- Fallacy of Soundness (assumes equivalence of species)
External Links
- Wikipedia: Equivalence relation [1]
Related claims
- Macroevolution has never been observed
- Range of variation is limited within kinds
- Fruit fly experiments produce only fruit flies
- The Law of Biology - life comes from life, and ancestors and descendants belong to the same species - has been proven
