Ch 17 Classification of Organisms Flashcards
how many species have biologists classified
2 mil
how many predicted insect species are there
30 mil
why have classification system been modified over the years
to include increasing understanding of how organisms have evolved
what does classification help with
- avoiding confusion when discussing organisms
- organizing info about Earth’s vast biodiversity
- simplifying the studying and sharing of info among scientists
what is taxonomy
the science of describing, naming, and classifying organisms
what is our current classification system based on
Carol Linnaeus’ Linnaean System
what are organisms grouped into in the linnaean system
hierarchical categories called taxa
on what characteristics are organisms grouped
their form and structure
what are the seven levels of grouping from larger to more specific categories
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species (recently added)
what is the binomial nomenclature
a two-part scientific name (genus name)
how can scientists around the world communicate unambiguously about organisms
by following sets of international rules on naming
what are scientific names designed to tell one about the organism
their relationships with other organisms of the same type
es: bears belong the the genus Ursus, so the first part of the sci name of all bears is Ursus
why are sci names often descriptive
to suggest something about the organism
ex: ursus maritimus is a polar bear (maritimus = white bear of ice region)
what are the rules for writing sci names
- genus name is capitalized and the species name is lowercase
- both words are italicized or underlined
- usually the names are “Latinized” or in Latin
what led to changes in the classification system to include 3 domains and 6 kingdoms
the 1977 analysis of rRNA nucleotide sequences by Carol Woese
what are the 3 domains of life
bacteria, archaea, and eukarya
domain bacteria
prokaryotic, aligns with kingdom eubacteria (true bacteria)
domain archaea
prokaryotic, aligns with kingdom archaebacteria. distinctive cell membranes and walls, able to survive in harsh e/ments
domain eukarya
eukaryotic, includes kingdoms protista, fungi, plantae, and animalia
what are most kingdoms divided into
phyla (animals) or divisions (plants)
what are phyla divided into
classes
what are classes divided into
orders, etc.
how may a current classification of an organisms change
as new info is learned about that organism and its relationship to other organisms
what may future investigations of organisms create
a new classification system based solely on DNA similarities
