Dichotomous Keys

Warm-up

Our planet is home to a very diverse group of species. But how many different species of living organisms do you think there are?

Why do we classify organisms?

Understand the natural world

Catalogue living organisms

Universal system of identifying organisms

Understand how species evolved

Background

Linnaeus developed the classification system that we use to group organisms

Binomial nomenclature (2 names)

3 domains, 6 kingdoms

Levels of Classification

Kingdom Phylum Class Order Family Genus Species

Animalia Chordata Mammalia Primates Hominidae Homo sapiens

Kingdom-Animalia

Phylum-Chordata

Class-Mammalia

Order-Carnivora

Family-Canidae

Genus-Canis

Species-lupus

Binomial Nomenclature

2 part species name, or scientific name Genus species

Caretta caretta

Eubalaena australis

Homo erectus

Homo sapien

Three-Domain System

Domain Archaea› Kingdom Archaebacteria

Domain Bacteria› Kingdom Eubacteria

Domain Eukarya› Kingdom Protista› Kingdom Fungi› Kingdom Plantae› Kingdom Animalia Staphylococcus

epidermidis

Six Kingdom SystemArchaebacteria

Prokaryotic

Unicellular

Nannoarchaeum equitans

Eubacteria Prokaryotic

Unicellular

Chlorobi

Protista Eukaryotic

Unicellular/multicellular

Euglena gracilis

Fungi Eukaryotic

Unicellular/multicellular

Penicillium candida

Plantae Eukaryotic

Multicellular

Carnegiea gigantea

Animalia Eukayotic

Multicellular

Homo sapiens

How does a dichotomous key classify organisms?

Uses pairs of contrasting, descriptive statements to separate and lead to the identification of an organism

What are some descriptive differences between these two objects?

Activity

Use the dichotomous key to identify the creatures

#2

Broadus archus

#6

Broadus anderson

#8

Narrowis georginia

Questions

Was it easy to identify the creatures even though you knew nothing about them?

What characteristics did they use?

Did they start with general or specific characteristics?

Group Activity

Break into groups to make your own dichotomous key