Naming and Reconstructing Fossils Help

Fossil Naming

The International Code of Zoological Nomenclature ( ICZN ) is the organization that determines the naming of an organism. It has specific rules, which maintain a standard of naming that all scientists know and understand.

All organisms, modern, ancient, and everything in between are classified into major groupings, according to specific characteristics. The more significant distinction is between the single-celled, no nucleus organisms ( Prokaryotes ) and multicellular, with a nucleus organism ( Eukaryotes ). These are the two major groups to remember with everything else placed below them.

Only one large category, Monera , is found below the Prokaryotes group. It contains bacteria and blue-green algae.

The Eukaryotes are divided into four major categories: the Protista , Fungi , Plantae , and Animalia . The Animalia category is further divided into Vertebrata (with a spinal column or backbone) and Invertebrata (no spinal column or backbone).

Paleontologists study fossils singly, but always within an ICZN-defined category. In fact, all living organisms are divided into separate groups and subgroups. When a plant or animal is named, for example, it is categorized within a wide system of narrower and narrower characteristics. When it can’t be defined any more, you are at the most basic level and scientific name. The complete ICZN classification system has hundreds of branches describing in finer and finer detail the differences between species.

Scientific names for different organisms have two parts. The first name, the genus , is always capitalized, while the species name is written second in lowercase letters. Both genus and species names are always italicized like in Centrosaurus apertus . Additionally, the genus name can be abbreviated like in A . fragilis ( Allosaurus fragilis ) or used alone to describe many species in one genus ( Allosaurus ).

Homo sapiens are the genus and species names for humans, while Tyrannosaurus rex is the genus and species of a meat-eating dinosaur. In this study of fossils, we will only name fossils to their genus level. To give you an idea of the main ICZN categories used to name fossils and living organisms, see Fig. 10-2.

Fig. 10-2. All living things are classified within a standard naming system.

Humans are categorized in the following way:

• Superkingdom → Eukaryota
• Kingdom → Animalia
• Phylum → Chordata
• Class → Mammalia
• Order → Primates
• Family → Hominidae
• Genus → Homo
• Species → sapiens
• When paleontologists talk about other fossil specimens in the Hominidae family, they may use the genus name Homo , but with different species names like Homo erectus or Homo habilis .

Reconstructing Fossils

Figuring out how a dinosaur might have looked from a site of scattered bones can sometimes be tricky. It’s like putting together a puzzle of a picture you have never seen and where some of the pieces are missing. From one discovery to the next, it sometimes takes decades to add another piece to the puzzle.

One famous goof happened when paleontologist, Gideon Mantell, was putting together the skeleton of the dinosaur, Iguanodon . He got it pretty much right, but put a small bone/horn at the end of the Iguanodon ’s nose, that turned out later (by comparing to other newly uncovered Iguanodons ) to actually be its thumb!

Reconstructing large plants is also tough. When plants die, they often come apart and fall in a heap. There is no good way to figure out what were branches, roots, or leaves, let alone where they connected together. The fact that different parts are found intact at different times leads paleontologists to name them as they are found. So the same plant may have different names for its flowers, leaves, and roots, until one day a complete specimen is found and all known information falls into place. In some locations, fossils are pretty much everywhere, and then in others it may be years, if ever, before another specimen of the same type are found again.

Practice problems of this concept can be found at: Fossils Practice Test