CLASSIFICATION:Organizing Life’s Diversity

HOW CLASSIFICATION BEGAN Organizing items can help you

understand them better & find them more easily.

Biologists organize living things into groupsClassification = the grouping of objects

or information based on similaritiesTaxonomy = the branch of biology that

classifies organisms.

WHY CLASSIFY?Three reasons: It helps to identify relationships between

organisms It requires scientists to identify important

characteristics of organisms It helps to avoid confusion

An organism may have misleading or multiple common names (ex. Seahorse or mountain lion/cougar/ panther/ puma)

Only one scientific name (Puma concolor)

ARISTOTLE Greek philosopher who

developed the first biological classification system

Classified things as plants or animalsHe didn’t know anything about

microscopic organisms like bacteria

Plants were grouped as herbs, shrubs, or trees

Animals were grouped by where they lived or spent most of their time - land, air, or water

LINNAEUS

Swedish botanist who developed our current classification system

Based on physical and structural similarities

Groupings revealed relationships between organismsScientists proposed that structural similarities

reflect evolutionary relationships

DOUBLE-NAME SYSTEM Binomial nomenclature = two-

word naming system developed by Linnaeus1st word = Genus2nd word = speciesLike a first & last nameHumans are Homo sapiens. House cats are Felis catus

Names are Latin It is no longer used in

conversation so it doesn’t change

BIOLOGICAL CLASSIFICATION

Scientists try to identify relationships as a basis for classification Compare internal & external structures,

geographical distribution, and genetics Makes it easier to understand biological diversity Dichotomous keys are used to identify the

characteristics by which organisms are classified. Benefits of taxonomy:

Offers a framework to study evolutionary relationships

Useful for identifying dangerous organisms (poison oak, holly berries, etc)

Economy – discovery of new resources for lumber, medicines, and energy

HOW LIVING THINGS ARE CLASSIFIED

Taxa/taxon = a group of organisms Seven Taxa categorize organisms from most

general to specific characteristics.1. Kingdom =group of phyla2. Phylum (in plants - division) = a group of classes3. Class = group of related orders4. Order = group of related families5. Family = group of genera that share

characteristics6. Genus (genera) = group of closely related

species7. Species = Latin name for an individual organism

EXAMPLE

lions, tigers, and leopards

Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Felidae Genus: Panthera Each are a different species

SIX KINGDOMS OF LIVING THINGS

o Kingdom Eubacteria Bacteria

o Kingdom Archaebacteria Chemosynthetic Bacteria

o Kingdom Protista Diverse catch-all group

o Kingdom Fungi decomposers

o Kingdom Plantae plants

o Kingdom Animalia animals