Chapter 18 Classification Taxonomy: The branch of biology that names and groups organisms according to their characteristics and evolutionary history.

Aristotle’s classification system Ancient Greek philosopher more than (2000) ago. He classified things as plant or animal He grouped animals into land dwellers, water dwellers, and air dwellers. What is the problem with this system? He grouped plants into three categories based on their stems.

Linnaeus’s classification system Carolus Linnaeus (1707-1778) Developed a system of grouping organisms into hierarchical categories. His system was based on an organisms morphology, its form and structure.

Levels of Classification Domain Kingdom Phylum/Division Class Order Family Genus Species

Examples: panther, human Eukarya Anamalia Chordata Mammalia Primates Hominoide Homo Sapien

Binomial Nomenclature (Scientific Name) Two part naming system for each species. Ex.1 Humans: Homo sapien Ex. 2 Ameba: Chaos chaos This two part name is also called the scientific name.

Modern taxonomists classify organisms according to phylogeny Phylogeny: The evolutionary development of an organ or other part of an organism evolutionary history

All cells can be divided in two groups Prokaryotes: unicellular, no nucleus, no membrane bound organelles Eukaryotes: Have nucleus and membrane bound organelles

Prokaryotic

Eukaryotes can be divided into two groups Autotrophs: make their own food Heterotrophs: obtain their food by consuming another organism

Plant Cell

Animal Cell

Recent changes in classification Three domains 1. Bacteria (eubacteria) True bacteria, unicellular prokaryotes 2. Archea (archeabacteria) Ancient bacteria, unicellular prokaryotes, some are photosynthetic, others are chemosynthetic Live in harsh environments without oxygen 3. Eukarya (eukaryotes)

Why do you think the number of kingdoms changed? Two kingdoms Five kingdoms Six kingdoms Scientific process: new information is discovered previous ideas are modified.

Six kingdoms 1. Eubacteria 2. Archaebacteria 3. Protista 4. Plantea 5. Fungi 6. Animalia

Eubacteria Have three basic shapes. round rod spiral

Archaebacteria Archaebacteria are found in extreme condition. Some are autotrophic Photoautotrophs Chemoautotrophs

Plantae Multicellular Photosynthetic Cell walls contain cellulose Non-motile

Protista Mostly single celled Very diverse group Some multicellular (Seaweeds) Eukaryotes Many are autotrophic

Fungi Heterotrophic Have cell wall Eukaryotes Very diverse

Animalia Heterotrophic Eukaryotic Motile

Activity: Classifying Organisms Using Dichotomous Keys pg 462 Do not cut out the fish just name them at the bottom of each picture