Unit 3 – Chapter 18

 The science of describing, naming, and classifying organisms  Classify – to arrange objects into groups based on their similarities  Carolus Linnaeus, father of modern taxonomy Binomial nomenclature

 A system of naming organisms based on a unique two-part scientific name Capitalize Genus name Lower case specific epithet “species” name Italicize or underline font  Example: Zea mays

 Which is the genus?  Which is the species?  How else can this be written?

 It is a dead language! Therefore it does not change!  To be precise and avoid confusion when describing a particular organism  Scientific names are the same regardless of the language of the speaker or writer

 Domain  Kingdom  Phylum  Class  Order  Family  Genus  Species

 One or more populations whose members can interbreed to produce fertile offspring  Reproductively isolated from other organisms  Share common evolutionary ancestry  Smallest unit of classification

 Geographically distinct populations  Within a species  Display characteristics that distinguish them from other populations of the same species  Can interbreed

Gilia latiflora subsp. excellens subsp. latiflora subsp. davyi Gilia tenuiflora Fig. 18-4, p. 355 Figure 18-4 Same genus, different species.

 A series of two contrasting statements  Useful in identification of unknown plants  Open to page 357

Fig. 18-6a, p. 357 b, a, a, b, b

Fig. 18-6b, p. 357 b, a, b, b

 The scientific study of the diversity of organisms and their natural (evolutionary) relationships  Phylogeny = “evolutionary history”  Monophyletic = a group of organisms that share “one common ancestor”

 Classification of organisms based on recency of common ancestry rather than degree of structural similarity  Focus on when evolutionary lineages (lines of descent) divide into two branches  Form a cladogram A diagram that illustrates evolutionary relationships & braking points