ORGANIZING LIFES DIVERSITY Chapter 17 Classification Ch 17

ORGANIZING LIFE’S DIVERSITY Chapter 17

Classification Ch. 17, Sec. 1

How Classification Began n Classification • grouping objects or info based on similarity n Taxonomy • branch of biology that classifies organisms n based on studies of different characteristics

Aristotle’s Classification System n Aristotle • Greek philosopher who developed one of the first system of classification

Aristotle’s Classification System n Aristotle • Grouped animals according to various characteristics, including habitat • NOT based on evolutionary relationships. n n Bats, birds and flies grouped together. Whales and fish grouped together.

Linnaeus’s Classification System n n Carolus Linnaeus was an 18 th century Swedish botanist Developed a method for classifying organisms still used today. Based on physical and structural similarities of organisms. System called Binomial Nomenclature

n Binomial Nomenclature • 2 word naming system • Always in Latin • Always italicized or underlined n n Ex. Homo sapiens Genus • 1 st word, capitalized • a group of closely related species n n Ex. Homo Species • 2 nd word, lower case • describes a characteristic of the organism n Ex. sapiens (means “wise”)

Scientific names and common names n All organisms have a scientific name and a common name • Common name = human • Scientific name = Homo sapien n The common name of an organism can vary from region to region. • Common Name n n United States: house sparrow Spain: gorrion domestico Holland: huismus The scientific name of an organism is recognized globally. • Scientific Name: Passer domesticus

How Living Things Are Classified n n Organisms are ranked in taxa (categories) that range from broad to specific In order from: • • 1. 2. 3. 4. 5. 6. 7. Kingdom Phylum Class Order Family Genus Species King Phillip Came Over From Germany Sunday

The 6 Kingdoms Ch. 17, Sec. 2

How are evolutionary relationships determined? n Evolutionary relationships are determined by: • Structural similarities n n n Homologous traits Breeding behavior Geographical distribution Chromosome comparisons Biochemistry

Classification Models pg. 452 n Phylogeny • Based mainly on physical or genetic relationships n Cladistics • Based mainly on common ancestry n Cladogram • A branching diagram that models the phylogeny of a species • Similar to family trees

The Six Kingdomes n Six kingdoms of organisms • Classified according to: Cellular structure n Methods for obtaining energy n

The Six Kingdoms n n n Eubacteria (Prokaryotes) Archaebacteria (Prokaryotes) Protists Fungi Plants Animals

Prokaryotes n n n Microscopic, unicellular bacteria Lack membrane-bound organelles Some are heterotrophs, some are autotrophs Oldest fossils are 3. 4 billion years old. Archeabacteria • Several hundred species • live in extreme environments n Eubacteria • Over 5000 species • Some cause diseases

Protists n n n Eukaryotes lack complex organ systems Lives in moist environments Some are autotrophs, some are heterotrophs Oldest fossils are 2 billion years old

Fungi n n Heterotrophs that absorb nutrients from materials in the environment Help decompose, break down organic material Oldest fossils 400 mya 50, 000 known species

Plants n n Photosynthetic eukaryotes Multicellular Autotrophs Oldest plant fossils more than 400 mya There are more than 250, 000 species

Animals n n n Multicellular heterotrophs Cells are organized into tissues and organs Oldest fossils are 600 mya