Taxonomy

Chapter 17: Organizing Life’s Diversity

What is Taxonomy?

Discipline of classifying organisms and assigning each organism a universally accepted name.

Why Classify?To study the diversity of life, biologists use

a classification system to name organisms and group them in a logical manner.

When taxonomists classify organisms, they organize them into groups that have biological significance.

Common Names vs.

Scientific NamesCommon Names can be confusing

one organism can have many different namesThe Cougar is also known as a: Puma,

Mountain Lion or Catamount

Each organism only has ONE scientific name (species name)No matter where you are in the world the

Cougar is Felis concolor

Assigning Scientific NamesAristotle was a Greek philosopher who

was the first to classify or group living things.

He classified organisms into two groups:

Plants and Animals

He subdivided those groups as well.

Plants were subdivided into: Herbs, Shrubs and Trees

Animals were subdivided based on their habitat and physical characteristics

Assigning Scientific Names A Swedish botanist named

Carolus Linnaeus developed Binomial Nomenclature, a two-word naming system for naming all species on earth. It is based on physical and

structural similarities Still used today

Why does everything have a weird name in Biology?

Everything in science is named using Latin.Why?

Latin is a dead language and won’t change meanings with slang or invention.

Example: “That is SO gay!!!”Merriam Webster Dictionary definition:

Gay – (gA) adjective; 1 a : happily excited : MERRY <in a gay mood> b : keenly

alive and exuberant : having or inducing high spirits <a bird's gay spring song>2 a : BRIGHT, LIVELY <gay sunny

meadows> b : brilliant in color

4 Reasons for using Latin

1. dead language and will not change

2. not misleading like a common name

3. more descriptive

4. basis for many other languages; English, French, Spanish, Italian and Portuguese

Binomial Nomenclature Each organism has a name consisting of two

words

Examples:

Homo sapiens Tyto alba

Common Name: Human Common Name: Barn Owl

Binomial Nomenclature

Homo sapiens Tyto alba

The first part of the scientific name is the genus. This word is always written first and the first letter is

capitalized. It appears in italics or is underlined.

Binomial Nomenclature

Homo sapiens Tyto alba

The second part of the scientific name is the specific epithet or species name. This word is always written second and the first

letter is lower-case. It appears in italics or is underlined.

The 8 Levels of ClassificationThey are, from largest to smallest

1. Domain (this is a relatively new level separates Archaea, Bacteria and Eukaryota)

2. Kingdom (separates plants from animals)

3. Phylum (separates into major groups within the Kingdom; plural: phyla)

4. Class (breaks Phyla down into smaller groups)

5. Order (even more specific)

6. Family (very similar characteristics)

7. Genus (reproductive grouping)

8. Species (most specific)

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

DidKingPhillipComeOverForGoodSoup

8 levels of Classification

Kingdom: AnimaliaPhylum: ChordataClass: AvesOrder: StrigiformesFamily: TytonidaeGenus: Tyto

Species: T. alba

Kingdom: Animalia

Phylum: ChordataClass: MammaliaOrder: PrimatesFamily: HominidaeGenus: Homo

Species: H. sapiens

You vs. Barn Owl

THINKING CRITICALLYOrganis

mCat Wolf Fly

Kingdom Animalia Animalia Animalia

Phylum Chordata Chordata Arthropoda

Class Mammalia Mammalia

Insecta

Order Carnivora Carnivora Diptera

Family Felidae Canidae Muscidae

Genus Felis Canis Musca

Species F. domesticus C. lupus M. domestica

THINKING CRITICALLY1. What are the kingdom

and class of Musca domestica?

2. From the table, which 2 animals are most closely related?

3. At what classification level does the evolutionary relationship between cats and wolves diverge (become different)?

Animal; insect

Cat and Wolf

Family Level

EVOLUTIONARY CLASSIFICATION

Biologists group organisms into categories that represent lines of evolutionary descent, or phylogeny, not just physical similarities.

Define Phylogeny: The study of evolutionary relationships among organisms.

Classification using Cladograms

Cladograms are diagrams that use derived characteristics to

illustrate evolutionary relationships.

Definition of Clade: A group of organisms, such as a species, whose members share homologous features derived from a common ancestor.

EVOLUTIONARY CLASSIFICATION

A B C D E F

Speciation: formation of two new species from one

Clade or lineage

TIME

Classification using Cladograms

The cladogram on the next slide shows the evolutionary

relationship among several vertebrates.

CLADOGRAM

Fur & MammaryGlands

Jaws

Lungs

Claws or Nails

Feathers

HagfishFish

FrogLizard

Pigeon

Mouse

Chimp

Cladogram

“Mini-Lab”

Using a Cladogram to Show Relationships

Procedure

1.The following table shows the presence or absence of six derived traits in the seven dinosaurs that are labeled A - G.

2.Use the information listed in the table below to answer the following questions.

Using a Cladogram to Show Relationships

Derived Traits of Dinosaurs

Dinosaur Trait DinoA

Dino B DinoC

Dino D

Dino E Dino F

Dino G

Hole in hip socket Yes Yes Yes Yes Yes Yes Yes

Extension of pubis bone No No No Yes Yes Yes Yes

Unequal enamel on teeth No No No No Yes Yes Yes

Skull has “shelf” in back No No No No No Yes Yes

Grasping hand Yes Yes Yes No No No No

Three-toed hind foot Yes Yes No No No No No

ANALYSIS1. ClassifyComplete the missing information on the right side of the partially completed cladogram.

1

6

5

4

2

2

B C D E F GA

Grasping Hand

Three-Toed Hind Foot