Evolution Evolution UnitUnit

Learning Goal #5: Explain how species are classified using the science of taxonomy.

Taxonomy• The branch of The branch of

science where science where scientists classify scientists classify organisms and organisms and assign each a assign each a universally universally accepted name.accepted name.

Why use a dead Why use a dead language?language?

•Scientist give a unique scientific name Scientist give a unique scientific name toto each species they know about whether each species they know about whether it’s alive today or extinct. it’s alive today or extinct.

• The scientific name comes from one of The scientific name comes from one of two “dead” languages – Latin or ancient two “dead” languages – Latin or ancient Greek. Greek.

Devil Cat

Ghost Cat

Mountain Lion

Screaming Cat

Puma

Florida Panther

Cougar

•There are at least 50 There are at least 50 common names for the common names for the animal shown on the animal shown on the previous 7 slides.previous 7 slides.

•Common names vary Common names vary according to region.according to region.

•Soooo……why use a scientific Soooo……why use a scientific name?name?

    •A two name system for writing scientific names.

•The genus name is written first.• (always Capitalized)

•The species name is written second.•(never capitalized)

•Both words are italicized if typed or underlined if hand written.

•Example: Felis concolor or F. concolorWhich is the genus? The species?

   

Binomial NomenclatureBinomial Nomenclature

•The evolutionary history of an organism, is the cornerstone of a branch of biology called systematic taxonomy.

Systematics, as systematic taxonomy is commonly called, is the study of the evolution of biological diversity.

                        

Phylogeny

A phylogenetic tree is a family tree that shows a hypothesis about the evolutionary relationships thought to exist among groups of organisms. It does not show the actual evolutionary history of organisms.

Phylogenetic trees are usually based on a combination of these lines of evidence:

    Fossil record

    Morphology

    Embryological patterns of development

    Chromosomes and DNA

Cladogram

• Diagrams that shows the evolutionary relationships between living organism.

• A key is a device for easily and quickly identifying an unknown organism.

• The dichotomous key is the most widely used type in biological sciences.

• The user is presented with a sequence of choices between two statements, couplets, based on characteristics of the organism. By always making the correct choice, the name of the organism will be revealed.

The Dichotomous Key

• Domain Archaea– Includes newly discovered cell types – Contains 1 kingdom – the Archaebacteria

•Domain Bacteria– Includes other members of old kingdom Monera – Has 1 kingdom – the Eubacteria •Domain Eukarya- Includes all kingdoms composed of organisms made up of eukaryotic cells

– Protista – Fungi – Animalia – Plantae

The Three Domains

The major classification levels,from most general to most specific

(several of these have subdivisions)

A group at any level is a taxon.

Kingdoms are divided into groups called phyla Phyla are subdivided into classes

Classes are subdivided into orders

Orders are subdivided into families

Families are divided into genera Genera contain closely related species

Species is unique

Categories within KingdomsCategories within Kingdoms

Six Kingdoms

 

EUBACTERIA

• Prokaryotes (no nucleus)• always unicellular (single-celled). 

• Bacteria.  • May have plant, fungus, or animal

characteristics.

ARCHAEA

• Prokaryotes; • always unicellular.  • Adapted to unusual and/or

extreme conditions, such as very hot, very salty, or no-oxygen environments. 

PROTISTA

• Eukaryotes (nucleus in cell); • mostly unicellular, or collections

of very similar cells.  • May have plant, fungus, or animal

characteristics.

.

PLANTAE

• Eukaryotes; • multicellular; • capable of photosynthesis

ANIMALIA

• Eukaryotes; • multicellular; • must obtain complex food

molecules from external source, • Usually capable of movement.

FUNGI • Eukaryotes; • almost all multicellular; • must obtain complex food

molecules from external source, absorbed through external surface. 

• Almost never capable of movement