Classification of Organisms

How many different types of organisms are there on Earth?

More than 2 million! Tremendous diversity Scientists estimate between 2 and 100 million species yet to be discovered

What is classification? Classification –a systematic arrangement of organisms into groups or categories according to specific scientific criteria Taxonomy – science of classifying organisms

Why Classify? Set up an organized system so scientists can communicate Study similarities and propose relationships between organisms Show evolutionary linkages between organisms

Common Names One species can have many different names –Example: Mountain lion, puma, cougar, or panther? Vary among languages and regions

Early Efforts at Naming Organisms Described the PHYSICAL characteristics –Example: Oak with deeply divided leaves that have no hairs on their undersides and no teeth around their edges Different scientists described different characteristics

Swedish botanist Based his system on STRUCTURAL similarities Developed a ranking system that went from broadest to most specific The father of modern taxonomy Carlos Linnaeus

Binomial Nomenclature The system used to identify all organisms using a two part Latin name Each SPECIES is assigned a two-part name –Population of organisms that share common characteristics and breed to produce fertile offspring

Keys to Binomial Nomenclature Felis domesticus Name has 2 part – Genus & species Must be in italics or underlined Genus (1 st word) must be capitalized Species must be lowercase

Correct or Incorrect? Triticum Aestivum - wheat Felis domesticus - cat canis lupus - wolf Canis familiaris - dog Populus deltoides - cottonwood

Hierarchy of Classification Kingdom Phylum Class Order Family Genus Species King Philip Came Over For Good Soup

Linneaeus’s Hierarchy of Classification Kingdom Phylum Class Order Family Genus Species King Phillip Came Over For Good Soup

Classification Example Kingdom – Animalia –Multicellular –Heterotrophic

Classification Example Phylum – Chordata –Nerve cord

Classification Example Class – Mammalia –Mammary glands –Breathes air –Four-chambered hearts –Endotherms (generate internal body heat)

Classification Example Order – Perissodactyla –Hooves –Odd number of toes on each foot –Herbivore

Classification Example Family – Equidae –Long heads and necks –Mane –Long slender tails

Classification Example Genus – Equus –Three toes

Classification Example Species – grevi –Distinctive striping pattern, with black stripes separated by narrow white bands –Stripes continue down the legs to the hooves. –There is a distinctive pattern on the hind quarters

Who am I? Equus grevi

How do scientists classify new organisms? They study their characteristics They try to see if they are similar to other already known organisms They group a new organism with others that have similar characteristics

Summary Scientists use Linnaean classification system to group organisms Organisms are grouped based on structural characteristics and information from all scientific fields Levels of classification start in large non- specific groups and end in small specific groups