BIOLOGY

Introduction to Taxonomy

The affinities of all the beings of the same class have sometimes been represented by a great tree... As buds give rise by growth to fresh buds, and these if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications.Charles Darwin, 1859

Taxonomy

Imagine two scientists . . .

One is from the United States and the other is from Germany

Both studying this organism

English: Hippopotamus German: Nilpferd

(translation, Horse of the Nile)

Taxonomy

The creation of a universal language for scientists so that (regardless of language or dialect) precise naming for organisms will occur

Latin was the selected universal language

Hippopotamus amphibus

Notice how this is written.

Genus capitalized,

species lowercase, in

italics

Taxonomy

Taxonomy is the science of grouping organisms based on their evolutionary similarities. Taxonomists analyze shared characteristics to determine evolutionary relationships between species.

Aristotle

Aristotle was the first person to attempt to classify things. He grouped everything into two groups; plants and animals. This system survived for nearly 2,000 years despite many mistakes. There was not an understanding of the microscopic world.

Carolus Linnaeus

In the 1700’s, a Swedish naturalist named Carolus Linnaeus designed a new system of classification in which every organism had a unique name.

He grouped organisms with similar structures together as a species. He also classified similar species into a group called genus. Every organism had a scientific name.

Linnaeus is known as the Father of Taxonomy

Categories of Classification

The organization for the taxonomy of organisms falls into eight levels.

DomainDoes Kingdom King Phylum Phillip Class Chews Order On Family Fat Genus Green Species Stems

The closer the evolutionary link between two organisms, the closer they will be placed taxonomically. Only members of the same species can interbreed and produce fertile offspring.

Categories of Classification

Humans are classified in the following way:

Domain – Eukarya Kingdom – Animalia Phylum – Chordata Class – Mammalia Order – Primate Family – Homonidae Genus – Homo Species – Sapien

Binomial Nomenclature

Classifying organisms is important because it:

1) Eliminates confusion caused by name differences in various regions

ex) The cougar, puma, panther, and mountain lion are all the same organism

2) All scientists will use the same language (Latin).

3) Organizes vast amounts of information.

4) Reveals evolutionary relationships.

Rules for Writing a Scientific Name

The scientific name of an organism is comprised of two words;the genus and the species name.

1) Genus name always comes first and is capitalized (Homo)

1) Species name comes second and is NOT capitalized (sapien)

Both names are either underlined or italicized (Homo sapien)

Common Name Scientific Name

Killer whaleHorseLionCrocodileDolphinCatDogGrizzly bearBoa constrictor

Equus caballusOrcinus orcaDelphinus delphisPanthera leoCrocodylus miloticusConstrictor constrictorUrsus arctosFelis domesticusCanis familiarus

Match the Common to the Scientific Name

The Six Kingdoms

Linnaeus classified all organisms into two kingdoms; Plantae and Animalia.

Kingdom Protista was added in the 1800’s Kingdom Monera and Fungi were added in the

1950’s. Eubacteria and Archaebacteria were added in the

1990’s

The number of Kingdoms used by taxonomists is still a subject of debate. A six Kingdom system is commonly used today.

The Six Kingdoms

Domains

A larger, more inclusive category than a kingdom.

3 domains: Bacteria (corresponds to kingdom Eubacteria) Archaea (corresponds to kingdom

Archaebacteria) Eukarya (kingdoms Fungi, Plantae, Animalia, &

Protista)

Three Domains

Domain Bacteria

• Unicellular• Prokaryotic (no nucleus)• Some photosynthesize/others don’t• Ecologically diverse

Domain Archaea

Unicellular Prokaryotic Live in extreme environments (volcanic hot

springs) Many can survive only in the absence of

oxygen Cell membranes contain unusual lipid not

found in any other organisms

Domain Eukarya

All organisms that have a nucleus Corresponding to kingdoms:

Fungi Plantae Animalia “Protista”

Kingdom Protista

EukaryoticMostly unicellular, some colonial (live in a group)All eukaryotes that don’t fit in the other kingdomsExample organisms: ameoba, and paramecium

Kingdom Fungi

EukaryoticMostly multicellularCell wallHeterotrophs (other–feeder)Secrete digestive enzymes into their food source,

and then absorb the small molecules into their bodies!

Example organisms: molds, mushrooms, and yeasts

Kingdom Plantae

EukaryoticMulticellularCell wallNonmotile (can’t move)Autotrophs (self–feeder)Photosynthetic – use energy from sunlight to

make their own foodExample organisms: green algae, mosses, ferns,

conifer, angiosperms

Kingdom Animalia

EukaryoticMulticellularHeterotrophicNo cell wallsMobile (able to move)Example organisms: sponges, corals, fish, frogs,

snakes, birds, and humans

The Six Kingdoms

Cladogram

Cladogram

Cladogram

Cladogram

Cladogram