Classification •method of logically grouping organisms based on common characteristics

TaxonomyTaxonomy

•does the actually grouping into the groups called TAXON (s – TAXA) with some kind of biological significance. •EX: Things that fly, swim, walk, have feathers, etc.

Early Systems of Classification

Biologists use a system of classification to organize information about the diversity of living things.

The History of Classification

Organizing Life’s DiversitySection 1

How many different terms can you think of for trying to tell someone

something is really good? WRITE ‘EM DOWN!

Need for common terms of description and classification so

that everyone knows what you are saing

Linnaeus’s System

Organizing Life’s Diversity

The History of Classification

Section 1

• He assigned two Latin names to each different species of organism

• This is their scientific name (binomial nomenclature)

Homo sapiens (human)

Ursus maritimus (polar bear)

Alba rubrum (red oak)

Ursus arctos (grizzly bear)

Taxonomic Categories

Organizing Life’s Diversity

categories used by scientists are part of a

nestednested-hierarchal system.

Each category is contained within another, and theyare arranged from broadest to most specific.

The History of Classification

Section 1

Linked

• Scientific names will always be in Latin.

• Latin is a dead language that will not evolve unlike other languages so it cannot change.• Genus name first– Always CAPITALIZED

• Species name second– Never capitalized

• Can either be…– Italicized– Underlined

ORGANISM Felis domesticus

Canis familiari

s

Haliaeetus leucocephalus

Danaus plexippus

English Cat Dag Eagle Butterfly

Spanish Gato Perro Águila Mariposa

French Chat Chienne L'aigle Papillion

German Katze Hund AlderSchmetterlin

g

Picture

The Taxonomic order:

DOMAIN

KINGDOM

PHYLUM

CLASS

ORDER

FAMILY

GENUS

SPECIES

The Taxonomic order:• From the biggest group to the smallest

group or taxa

Taxa Human Cat DogKingdom Animalia Animalia AnimaliaPhylum Chordata Chordata ChordataClass Mammalia Mammalia MammaliaOrder Primate Carnivora CarnivoraFamily Hominoidae Felidae CanidaeGenus Homo Felis Canisspecies sapiens catuslupusWhich two organisms are more closely related and why?

Organizing Life’s Diversity

Phylogeny is the evolutionary history of a species.

The phylogenic species concept defines a species as a cluster of organisms that is distinct from other clusters and shows evidence of a pattern of ancestry and descent.

Section 2

To classify a species, scientists construct patterns of descent by using characters.

Concepts in Motion p497

Morphological Characters

Shared morphological characters suggest that species are related closely and evolved from a recent common ancestor.

Organizing Life’s Diversity

Analogous characters are those that have the same function but different underlying construction.

Section 2

Homologous characters might perform different functions, but show an anatomical similarity inherited from a common ancestor.

Birds and Dinosaurs

Organizing Life’s Diversity

Compare birds and dinosaurs:

Hollow bones

Theropods have leg, wrist, hip, and shoulder structures similar to birds.

Some theropods may have had feathers.

Modern Classification

Section 2

Biochemical Characters concepts in motion p498

Organizing Life’s Diversity

amino acids and nucleotides are used to determine evolutionary relationships among species

DNA and RNA analyses are powerful tools for reconstructing phylogenies

Section 2

Organizing Life’s Diversity

The similar appearance of chromosomes among chimpanzees, gorillas, and orangutans suggests a shared ancestry.

Modern Classification

Section 2

Organizing Life’s DiversitySection 2

Cladistics reconstructs phylogenies based on shared characters.

ancestral character found within the entire line of descents

derived characters are present for one group line but not in common ancestor

Cladograms (concepts in motion p496)

the closer the clades the more shared characters

Kingdoms and Quiz (video p501)