1. Classifying
To classify means to group ideas, information or objects based on similarities. We classify many places- like grocery stores, bookstores, and department stores.

2. Early Classification Systems
Aristotle, a Greek philosopher, developed a system to classify living things. The science of classifying and naming organisms is called taxonomy. Aristotle’s classification system had two kingdoms- plant and animal.

3. Aristotle’s Classification System
Aristotle divided the animal kingdom into organisms based on whether they lived in the air, on land, or in the sea. Amphibians, and other organisms, didn’t fit nicely into this system. He classified plants based on their size and structure.

4. Carolus Linnaeus
Carl Von Linne, better known as Carolus Linnaeus, was a Swedish physician and naturalist that created a system to classify organisms based on their body structures and systems, size, shape, color, and method of obtaining food.

5. Binomial Nomenclature
Linnaeus created a two-word naming system called binomial nomenclature. This system gave all organisms a scientific name in Latin. The first part of the scientific name was the genus and the second the species.
Felis lynx
Canis rufus

6. Species
Organisms belonging to the same species can mate with one another to produce fertile offspring. Organisms like lions and tigers that are different species can have offspring together, but the offspring are sterile.