Classification - Lawrence USD 497

Transcript Classification - Lawrence USD 497

Classification of Living Things

• Classification: Grouping life based on similarities • Why classify? To study the vast diversity of life and organize information in a common language.

Species of Organisms

• There are organisms • This is lived!!!!!

identified 13 billion known species of only 5% of all organisms that ever • New organisms are still being found and copyright cmassengale 2

Confusion in Using Different Languages for Names

Latin Names are Understood by all Taxonomists

Taxonomy: the classification and naming of organisms.

• Scientific names are universal.

Early Taxonomists

•2000 years ago, Aristotle was one of the first taxonomists •Aristotle divided organisms into plants & animals

Carolus Linnaeus 1707 – 1778

• 18th century Swedish taxonomist • Classified organisms by their physical structure • Developed naming system still used today copyright cmassengale 7

Linnaeus

’

s Hierarchical System

Seven taxonomic categories: Kingdom Animal Phylum Arthropoda Class Insecta Order Lepidoptera Family Danaidae Genus Danaus Species plexippus

Taxon

General term for any one of these categories in the hierarchy.

(Plural of taxon is taxa.)

The system can change as scientists gather new information! (DNA, new discoveries) • Now we have “ Domain ” level above the Kingdom

Hierarchy-Taxonomic Groups

• • • • • • • • Domain Kingdom

BROADEST TAXON

Phylum (Division – used for plants) Class Order Family Genus Species

Most Specific

hierarchy

http://www.aquatax.ca/images/classificationFigure.jpg

Now come up with your own mnemonic device to remember the order of taxa from domain to species.

D K P C O F G S

Rules for Naming Organisms

• The

International Code for Binomial Nomenclature

contains the rules for naming organisms • This prevents duplicated names copyright cmassengale 16

Binomial nomenclature = two part name:

Genus species

• • Genus is Capitalized, both words are italicized or underlined in handwriting.

Latin or Greek describes organism • Ex: Homo sapiens, Drosophila melanogaster, Toxicodendron radicans,

Peromiscus maniculatus

Binomial Nomenclature

Domains

• Broadest , most inclusive taxon • Three domains • Archaea and Eubacteria • Eukarya bound organelles are unicellular prokaryotes (no nucleus or membrane-bound organelles) are more complex and have a nucleus and membrane copyright cmassengale 19

ARCHAEA

• Probably the 1 st cells to evolve • Live in HARSH environments • Found in: – Sewage Treatment Plants – Thermal – Hot Springs or Geysers that are acid – Very or Volcanic Vents salty water (Dead Sea; Great Salt Lake) copyright cmassengale 20

ARCHAEAN

EUBACTERIA

micromovie stars

• Our bodies are covered with them!

• Some may cause DISEASE • Found in ALL HABITATS harsh ones • Important decomposers except for environment • Commercially important in making cottage cheese, yogurt, buttermilk, etc.

Live in the intestines of animals

EUKARYA

: Cells have a nucleus!

Divided into 4 Kingdoms:

• Protista

(protists, algae…)

• Fungi

(mushrooms, yeasts …)

• Plantae

(multicellular plants)

• Animalia

(multicellular animals) copyright cmassengale 25

Protista

•Most are unicellular •Some are multicellular •Some are autotrophic , while others are heterotrophic •Aquatic copyright cmassengale 26

Fungi

• Multicellular, except yeast • Absorptive heterotrophs (digest food outside their body & then absorb it) • Cell walls made of chitin copyright cmassengale 27

Plantae

•Multicellular •Autotrophic •Absorb sunlight to make glucose – Photosynthesis •Cell walls made of cellulose copyright cmassengale 28

• Multicellular • Ingestive heterotrophs (consume food & digest it inside their bodies) • Feed on plants or animals

Animalia

Plantae is divided into about 12 phyla and comprise about 270,000 species. Animalia is split into about 33 phyla and contains about 800,000 species (although this is probably a drastic underestimate of the true figure). Fungi have five phyla and about 100,000 species. Eubacteria have three phyla and a number of species that is difficult even to estimate – some authors suggest 1,000,000,000 (a billion) but even this could be a considerable underestimate! Archaea are poorly known and there are currently three main (and five tentative) phyla that have been created based largely on laboratory cultures (estimates of total phyla range from 18 to 23). The most recent list I can find (1999) contains 209 species. Protista comprise some 20 to 50 phyla and about 23,000+ species.

Dichotomous Keys

• An identification key that contains pairs of contrasting descriptions. • After each description, a key either directs the user to another pair of descriptions or identifies an object http://www.amnh.org/learn/biodiversity_counts/ident_help/Text_Keys/arthropod_keyA.htm