Classification

Why do we need to classify organisms?

- easier to find organisms

- easier to see the similarities and differences of the organisms

- easier to see trends in the organisms
- easier to retrieve information from the classification

How many species are there?

:13 billion

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

What is classification?

• Classification is the arrangement of organisms into orderly groups based on their similarities. 
• Classification is also known as taxonomy
• taxonomists are scientists that identify & name organisms                                                                    

Benefits of classifying

• Accurately & uniformly names organisms
• Prevents misnomers such as starfish and jellyfish that aren't really fish
• Use same language (Latin or some Greek) for all names. 

Binomial nomenclature

Genus      species

Problems in classifying organisms

• Species are always changing.
• Mutation
• Interbreeding

Naming of Organisms


Print form

Homo sapiens

Written form

Homo sapiens

Classification Group

• Taxon (Taxa-plural) is a category into which related organisms are placed.
• There is a hierarchy of groups(taxa) from broadest to most specific
• Domain-Kingdom-Phylum-Class-Order-Family-Genus-Species

Domains

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

Taxons

• Most genera contain a number of similar species, with the exception of Homo that only contains more different types of organisms than the preceding category.

Examples

Human classification

Domain Eukarya-->cells with nuclei

King Animalia--> Multicellular, motile, ingestion of food

Phylum Chordata--> Dorsal supporting rod and nerve cord

Class Mammalia--> Hari, mammary glands

Order Primates--> Adapted tp climb trees

Fmaily Hominidae--> Adpted to walk erect

Genus Homo...

Species

Pictures taken from http://sarahfoo26106biologyjournal.blogspot.sg/