Classification

Why do we need to classify organisms?

· Easier to identifrey similarities and differences.

· Can identify organism through the charcteristics of it

How many species are there?

50 billion(my guess)

157

100 trillion

1.4, 8.7, 1.7 million

100 million

The answer is... 13 billion known species of organisms.

This is only 5% of all organisms that ever live!

New organisms are still being identified.

What is classification?

· Classification à arrangement of organisms/groups based on their similarities

· Also known as taxonomy.

· Taxonomists are scientists that identify and name organism.

Benefits of classifying

· Accurately & uniformly named organisms.

· Prevents misnomers such as starfish & jellyfish that aren’t really fish

· Uses same language (Latin or some Greek) for all names.

Human in scientificàHomo sapiens sapiens

When did scientists begin classifying living things?

· 2000 years ago, Aristotle was the first taxonomist.

· He divided organisms into plants & animals.

· He subdivided by the habitat.

· John Ray, a botanist, was the first to use Latin name

· His names were very long descriptions telling their characteristics.

· 18^th century taxonomist

· Classified by structure

· Developed naming system

Problems in Classifying organisms

· Species are always changing

· Inter-breeding

Standardized Naming

· Binomial nomenclature used

· Genus species

· Latin or Greek

· Italicized in print

· Capitalize genus, but NOT species.

· Underline when writing

For example: Turdus migratorius

When written: Turdus migratorius

Rules for naming

The international code for binomial nomenclature contains the rules for naming organisms. International Naming Congresses must approve all names. This prevents repeated names.

       

 Classification groups

· Taxon (tax-plural) is a category into which related organisms are placed.

· There is a hierarchy of groups (taxa) form broadest to most specific.

· Domain, Kingdom, Phylum, Class, Order,

Domains

· Broadest, most inclusive taxon

· Three domains

· Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles)

· Eukarya are more complex and have a nucleus and membrane-bound organelles.

Taxons

· Most genera (plural) contain a number of similar species, with the exception of HOMO that only contains modern humans.

Kingdom, phylum  (chordateàbackbone), class ( mammalia àmammals), order, family, genus à finer characteristics, speciesàinternal structures

(king Philip came over for gooseberry soup)