Unit 9

Taxonomy

Part I Unit 9: Taxonomy

Finding Order in Diversity !  Taxonomy- the classification system used to

name organisms and group them in a logical manner.

!  Carolus Linnaeus developed a naming system called binomial nomenclature where each species is assigned a two-part scientific name. ! The first word is capitalized, and the second word is

lower cased. They are both written in italics.

Linnaeus’s System of Classification !  Linnaeus’s system of classification includes 7

levels, known as taxon. ! Kingdom: Plantae and Animalia- the largest taxon ! Phylum ! Class: Mammalia, Reptilia, Aves, Amphibia ! Order ! Family ! Genus ! Species- the smallest taxon

!  The binomial name uses the genus and species names.

Why Taxonomy is Important Scientific classification Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Felidae Subfamily: Felinae Genus: Puma Species: Puma concolor

Common Names: Cougar, Mountain Lion, Puma, Panther Scientific Name: Puma concolor

Why Taxonomy is Important

Common Name: Eastern Red Cedar Scientific Name:Juniperus virginiana

Scientific classification Kingdom: Plantae Division: Pinophyta Class: Pinopsida Order: Pinales Family: Cupressaceae Genus: Juniperus Species: Juniperus. virginiana

Why Taxonomy is Important

Common Name: Cedar of Lebanon Scientific Name:Cedrus libani

Scientific classification Kingdom: Plantae Division: Pinophyta Class: Pinopsida Order: Pinales Family: Pinaceae Genus: Cedrus Species: C. libani

Linnaeus’s System of Classification

Dichotomous Keys

!  QUESTION: Once an organism has classified using a taxonomical system, how can you learn to tell it apart from other similar organisms? !  Like those in the same Family or Genus? !  For example: a silver maple tree (Acer saccharinum) , red maple

tree (Acer rubrum), and sugar maple tree (Acer succharum)

!  ANSWER: A key. A dichotomous key is a tool that allows the user to determine the identify of items in the natural world.

Part II Unit 9: Taxonomy

Warm Up Exercise !  Who came up with the system of taxonomy that we still use

today? !  What is the name of the system where each species gets 2

names? !  What do those two names represent?

Evolutionary Classification !  Phylogeny- shows evolutionary relationships among

organisms. !  Biologists group organisms into categories that represent lines

of evolutionary descent, not just physical similarities. This is called evolutionary classification.

Classification Using Cladograms

!  Derived Characters- characteristics that appear in recent parts of a lineage but not in its older members.

!  Cladogram- uses derived characters to show the evolutionary relationships among a group of organisms.

Similarities in DNA and RNA !  The genes of many organisms show important similarities at

the molecular level. Similarities in DNA can be used to help determine classification and evolutionary relationships.

Molecular Clocks !  Molecular Clock- uses

DNA comparisons to estimate the length of time that two species have been evolving independently.

Exit Slip !  Traditional classification groups organisms together based on

!  derived characters. !  similarities in appearance. !  DNA and RNA similarities. !  molecular clocks.

!  In an evolutionary classification system, the higher the taxon level, !  the more similar the members of the taxon become. !  the more common ancestors would be found in recent time. !  the fewer the number of species in the taxon. !  the farther back in time the common ancestors would be.

Part III Unit 9: Taxonomy

Warm Up Exercise ! What are derived characters? ! Can two organisms be classified in the same

family but be more genetically similar to organisms in a different family?

Kingdoms and Domains

! The First 5 Kingdoms: Plantae, Animalia, Protista, Fungi, and Monera. ! In the 1990’s, monera was subdivided into eubacteria

and archaebacteria, for a total of 6 kingdoms.

! The 3 Domains: Eukarya, Bacteria, Archaea. ! Eukarya includes plants, animals, fungus, and protists. ! Bacteria includes eubacteria. ! Archaea includes archaebacteria.

The Three Domains

! Bacteria - unicellular prokaryotes ! Have thick, rigid cell walls that surround a cell

membrane.

! Archaea - unicellular prokaryotes ! Live in extreme environments, and many can

only survive in the absence of oxygen.

The Three Domains ! Eukarya - all organisms containing a nucleus. ! Protista- eukaryotes not classified as plants,

animals, or fungi. ! Fungi- heterotrophs. Most feed on dead or

decaying organic matter ! Plantae- multicellular photosynthetic

autotrophs. Nonmotile. Have cell walls containing cellulose.

! Animalia- multicellular and heterotrophic. No cell walls.

Classification of Living Things

Exit Slip ! What are the three domains of life? ! What are the six kingdoms of life?