Invertebrate Paleontology - Invertebrate Terminology in Science

Invertebrate Terminology in Science

In the many decades since Jean-Baptiste de Lamarck, a pioneering biologist and evolutionist, first conceptualized and coined the category "Invertebrata" (between 1793 and 1801) and the term "Biology" (in 1802), zoology has come to recognize that the non-vertebrate category is not a scientifically valid, monophyletic taxon. Evolutionary biology and developmental biology (a.k.a. "evo-devo") now consider the term "Invertebrata" to be both polyphyletic and paraphyletic. Nevertheless, most earth science departments continue to employ this term; and paleontologists find it both useful and practical in evaluating fossil invertebrates and—consequently -- invertebrate evolution.

However, there is one contemporary caveat: Paleobiologists and microbiologists in the 21st century no longer classify one-celled "animal-like" microbes either as invertebrates or as animals. For example, the commonly fossilized foraminifera ("forams") and radiolarians -- zooplankton both formerly grouped under either an animal phylum or animal sub-kingdom called Protozoa ("first animals") -- are now placed in the kingdom or super-kingdom Protista or Protoctista (and thus called protists or protoctists).

Thus modern invertebrate paleontologists deal largely with fossils of this more strictly defined Animal Kingdom (excepting Phylum Chordata), Phylum Chordata being the exclusive focus of vertebrate paleontology. Protist fossils are then the main focus of micropaleontology, while plant fossils are the chief focus paleobotany. Together these four represent the traditional taxonomic divisions of paleontologic study.