Sunday, March 29, 2009

Polymorphism, Intraspecific Variation, Dimorphism, Covariation

A few terms that at first seem to be self explanatory. The first two seem to be interchangeable as do the last two. Reading a paper the other day, the title used one term but the body of the paper was filled with the other term. Could someone fill me in on the correct usage of these four terms, are they really all about the same. For years an ammonite was an ammonite until I found out that some were ammonoids, actually all are ammonoids and I was just using the wrong term for the whole group. It just took an explanation... like the one I am looking for now.
There are a few posts in this blog labeled with the term "Polymorphism", this term seems to have a deeper meaning than I was intending, so from now on this term will be replaced with "Intrapsecific variation", though not as snazzy sounding it probably is more in line with my intended meaning.


  1. Ammonites always refer to the Cretaceous age.- Ahmad Rosli

  2. Thank you Ahmad, Jurassic ammonoids are also ammonites, or Ammonitids. Most Triassic ammonoids are ceratites, or Ceratitids and most Paleozoic ammonoids are Goniatites, or more technicaly Goniatitids.

  3. Thank you for the explaination.
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    Ahmad Rosli