Classification Unit 3

Classification Activity• Please sit down if you:• Are taller than 5’9”• Have blonde Hair • Have brown Eyes• Are left-Handed

Why Classify?• To study the diversity of life, biologists use a classification system to

name organisms and group them in a logical manner.

• Taxonomy: science of classification

• By using a scientific name, scientists can be sure everyone is discussing the same organism.

mountain lion ? puma? cougar ? panther?

 Scientific name = Felis concolor

Assigning Scientific Names• Aristotle attempted to classify organisms based on where they lived

- land, water or air.

• With the invention of the microscope, classifying the diversity of life became difficult.

• A major step was taken by Carolus Linnaeus who developed binomial nomenclature (two-name naming system.)

• In binomial nomenclature, each species is assigned a two-part scientific name, which is always written in italics. First name is capitalized and second is lowercase.

Binomial Nomenclature

Ursus arctos

Genus Species

Dichotomous Key• Tool to help user identify living and non-living things.

• Dichotomous comes from two Greek words that together mean, “divided into two parts”.

• In each step of the key, only two choices are given; a direction is given or the organisms scientific name.

Dichotomous Key

Dichotomous Key Activity

Class Activity!

Make your own Dichotomous Key

Warm-Up!

Linnaeus’s System of Classification

• Linnaeus's hierarchical system of classification includes eight levels:• Domain • Kingdom•  Phylum•  Class•  Order•  Family•  Genus•  Species

• Each level is called a taxon (pl. taxa).• Species: organisms that look alike and inter-breed under

natural conditions.

Trick!• Definitely Domain• Keep Kingdom• Pond Phylum• Clean Class• Or Order• Froggy Family• Gets Genus• Sick Species

Read and Respond

Warm-Up!• What are the eight levels of classification?

• What are the 3 domains?

• What are the 6 kingdoms?

Kingdoms and Domains• Linnaeus's two kingdoms, Animalia and Plantae did not adequately

represent the diversity of life.• Microorganisms became kingdom Protista.• Mushrooms, yeasts and molds were placed in Fungi.• Later, bacteria were named kingdom Monera.• More recently, kingdom Monera was subdivided into two groups:

Eubacteria and Archaebacteria.

Domains• Three domains• Eukarya (Protists, Fungi, Plantae, Animalia)• Bacteria (Eubacteria)• Archaea (Archaebacteria)

Domain Bacteria

Domain Bacteria• Extremely Diverse• Some photosynthetic • Some pathogenic (causing disease)• Some need oxygen to live, others are killed by oxygen

StreptococcusEscherichia coli

Domain Archaea

Domain Archaea• Live in extreme environments• Volcanic hot springs• Brine pools• Bottom of the ocean

• Many can only survive in the absence of oxygen

Methanogens

Halophiles

Domain Eukarya

Eukarya-Protista• Great variety• Three basic groups• Animal-like• Plant-like• Fungi-like

Amoeba Paramecium

Eukarya-Fungi• Feed on dead or decaying matter• Secrete digestive enzymes, then absorb small molecules • Cell walls made of chitin

Eukarya-Plantae• Non motile-cannot move from place to place• Cell walls made of cellulose

Eukarya-Animalia• Heterotrophic – must eat others to survive • No cell walls

Time to Practice!• Pg 461: # 3-5• Pg 463: Classify the leaves using dichotomous key• Pg 465: #1-5, 8-10