Taxonomy

The science of naming organisms.

Why Classify?

Aristotle Did It

• Plant or animal?

• If an animal, does it

– Fly

– Swim

– Crawl

• Simple classifications

• Used common names

Carolus Linnaeus did it better

• Based his system on homologous structures

• Developed binomial nomenclature

• First word = genus name (capitalized)

• Second word = species name (not capitalized)

Father of modern

classification

Why binomial nomenclature?

• Much easier than a 10+ word name under old “polynomial system”

• Same name no matter where you go

• Less confusion

• Names used to be…

“Oak with deeply divided leaves that have no hairs on their undersides and not teeth around their edges.”

Taxonomic hierarchy

• Names organisms and

their relationships from

very broad to very specific

Scientific Names You Need to Know

• Homo sapiens

• Canis lupus

• Felis domesticus

• Ursus arctos

• Ursus maritimus

• Ursus americanus

Record the taxa for Homo sapian: • Domain-

• Kingdom -

• Phylum-

• Class-

• Order-

• Family-

• Genus-

• Species-

What is a species anyway?

Species- A group of organisms that can reproduce and produce viable offspring

How many are out there?

Scientists currently estimate that

There are 10 million species worldwide

Over 5 million live in the tropics

Most unnamed species are small or microscopic

Why is taxonomy useful?

• Helps prevent confusion among scientists

• Helps to show how organisms are related

• Can be used to reconstruct phylogenies – evolutionary histories – of an organism or group

Traditional vs Modern Taxonomy

• Linneaus (1700’s)

• 2 Kingdoms

(KPCOFGS)

• Based on homologous structures

• Modern (2000’s)

• 3 Domains

• 6 Kingdoms

(DKPCOFGS)

• Based on evolutionary relationships (DNA, proteins, embryology, fossil record, homologous structures

A note on cladograms

Cladogram- diagram that show evolutionary relationships

• Graph showing when different groups diverged from a common ancestral line

• Points where they diverge are often noted with a feature that was different between ancestral group and a “new” feature in the group that split off.

Bird Cladogram

Classification vs. Cladogram

The 6 kingdoms

• Bacteria - 1.Eubacteria

• Archaea – 2.Archaebacteria

• Eukaryotes – 3.Fungi

– 4.Protista

– 5.Animal

– 6.Plantae

Overview of the 6 kingdoms

• Archaebacteria – Unicellular

– Live in extreme environments

– Prokaryotic

• Eubacteria – Unicellular

– Prokaryotic

– “Common bacteria”

Overview of the 6 kingdoms

• Protista – Eukaryotic

– Unicellular or colonial

– Lots of different life styles

• Fungi – Cell walls made of chitin

– Eukaryotic

– Multicellular

– External heterotrophs

Overview of the 6 kingdoms

• Plantae – Eukaryotic & Multicellular

– Cell walls made of cellulose

– Autotrophic

• Animalia – Eukaryotic & Multicellular

– No cell walls

– Internal heterotrophs

Vocab to review

• Taxonomy

• Classification

• Dom,King, Phyl, Class, Order, Family, Genus, Species

• Binomial Nomenclature

• Autotrophs/ Heterotrophs

• 6 Kingdoms-

• Eukaryotes/Prokaryote

Practice Questions

1. A tool often found in a field guide that is used to identify organisms is called

a. Cladogram

b. Binomial Nomenclature

c. Dichotomous Key

d. taxonomy

2. Organisms that eat other organisms for food are called _________________.

3. The two part naming system developed by Linneus is called _________________.

4. The geologic timeline covers a very long time, how far does the current timeline go back? (How old is the earth?)

5. Which of the following domain includes organisms that can be found in extreme temperatures of deep sea vents?

a. Bacteria

b. Eukarya

c. Archae

d. Animalia

6. Humans are

a. Ingestive autotrophs

b. Absorptive autotrophs

c. Ingestive heterotrophs

d. Absorptive heterotrophs

7. In Aristotole’s system of classification, animals are grouped according to their

a. Size

b. Habitat

c. Structrue

d. ancestors

8. Unicellular eukaryotes belong to the kingdom ______________?

9. Unicellular prokaryotes that are found in the back of your refrigerator are called ___________?

10. Organisms that lack a nuclear membrane are called _______________?