Fossils and Geologic Time Topics


Fossil organisms are named like present-day organisms.  Animals are divided into two major groups, invertebrates and vertebrates.  Plant fossils and ichnofossils are also discussed here.

1. Fossil names

2. Invertebrate animals

3. Vertebrate animals

4. Plants

5. Ichnofossils

Fossil Names

• Fossil organisms, like present-day organisms, are grouped and named based on a similarity of form.  Each organism has two names, so the naming system is called the binomial system of scientific nomenclature.

• All organisms are organized into groups related by certain basic features.  For example, all mammals are warm-blooded, but some mammals fly (bats), some swim (whales), and some walk on two legs (humans).

The chart below shows examples of the scientific nomenclature for three common organisms: the human, the common edible East Coast oyster, and the dogwood tree.  Humans are vertebrate animals.  Oysters are invertebrate animals.  Dogwood trees are plants.

  Human East Coast Oyster Dogwood
Kingdom Animalia Animalia Plantae
Phylum Chordata Mollusca Tracheophyta
Class Mammalia Pelecypoda Angiospermae
Order Primata Eulamellibranchia Atiales
Family Hominidae Osrteidae Cornaceae
Genus Homo Ostrea Cornus
Species H. sapien O. virginica C. florida

• Organisms are known by their genus and species names.  Humans, for example, are called Homo sapiens.

The state fossil of Virginia is this clam, found in the Coastal Plain.  Its scientific name is Chesapecten jeffersonius. (Photograph by Parvinder Sethi)