Organizing Life’s Diversity • Classification: the grouping of objects or

organisms based on their similarities• Biologists use a system of classification to

organize information about the diversity of living things

• Taxonomy is a branch of Biology that is the science of classifying/grouping and naming of organisms

Earth’s Amazing Diversity

Aristotle’s Classification System • Greek philosopher who developed first classification

system • Divided all organisms into 2 GROUPS: • Non motile (plants) • Plants were grouped by:• Size small, medium, large for things like herbs,

shrubs, and trees• Motile (animals) • Animals were grouped by:• Their Habitat (air, water, land)• Morphology (form or structure) • “Red-Blooded” and “Bloodless”

Linnaeus's Classification System • 18th Century Swedish Naturalist who broadened

Aristotle’s classification method • Created a system of naming organisms by their

structures and their behavior. (He didn’t realize it but he was also classifying them by evolutionary relationship).

• Linnaeus’s system of naming and grouping organisms is called “Binominal Nomenclature” and this system is still valid today.• Written in Latin • Gives each species a scientific name that has two parts:• First part: Genus• Second part: Species

Binomial Nomenclature• Genus: CAPITALIZED (noun)

• means beginning • Species: lowercase (adj.) • Example: • Humans: Homo (man) sapien (wise/thinking)• Whitetail Deer: Odocoileus virginianus• Italicized if printed, Underlined if written

• Organisms have a scientific name and a common name.• Scientific name is the Genus species name• Common name is what the organism is commonly

called and is not used in the scientific community

Binomial Nomenclature• The common name of an organism is not used by

scientists because one species may have many different common names depending on where the animal lives.• For example, the Mountain Lion, Mountain Cat, Black

Panther, Painter, Catamount, Ghost Cat, Cougar and the Puma are all the same organism. People that live in different areas just call it different things.

Can you think of any other

organisms that have multiple

common names?

The “New” Evolutionary Classification • Categories represent lines of evolutionary descent, not

just physical and behavioral similarities • This new method is called: Evolutionary

Classification • Scientists classify organisms based on their

Evolutionary beginnings • Cladograms are useful diagrams that are used to show evolutionary relationships between organisms (You may also hear this called a Phylogenetic Tree).

Cladograms/Phylogenetic Trees• Scientists use these to understand how one lineage branched

from another in the course of evolution

• To place organisms in a Cladogram, scientists consider ancestry and homologous characteristics not found in other organisms.

• A small number of characteristics are used to define each group.

• Claddists assume that each successive group has a more recent common ancestor that other previously branched species don’t share.

Cladograms/Phylogenetic Trees• Scientists use these to understand how one lineage branched

from another in the course of evolution

• To place organisms in a Cladogram, scientists consider ancestry and homologous characteristics not found in other organisms.

• A small number of characteristics are used to define each group.

• Claddists assume that each successive group has a more recent common ancestor that other previously branched species don’t share.