BIO 101 - Week 2 Lecture Slides.pdf

Classification of Plants and Other Organisms BIO 101 – General Botany Learning Objectives Define Taxonomy Enumerate the different taxonomic rank based on Linnaean classification 2 Taxonomy 3 Taxonomy How can we...

Classification of Plants and Other Organisms BIO 101 – General Botany Learning Objectives Define Taxonomy Enumerate the different taxonomic rank based on Linnaean classification 2 Taxonomy 3 Taxonomy How can we classify plants into groups? Size, Color, Use? 4 Taxonomy Taxonomy Science of describing, naming, and classifying organisms Classification Arranging organism into groups based on their similarities 5 Learning Objectives Define Taxonomy Enumerate the different taxonomic rank based on Linnaean classification 6 Prior Nomenclature Used up 10-12 word Latin description Ex. Tradescantia ephemerus phalangoides tripetalum non repens Virginianum granineum The annual upright Tadescantia from Virginia with a grasslike habit, three petals, and stamens with hairs like spide legs Linnaeus simplified to Trandescantia virginiana 7 Linnnaean Classification System Designed in mid-18th Century by Carl Linnaeus Published Species Planatarum Linnaean Classification – binomial nomenclature Based on visual observations of flower parts Ex. All flowers of the same kind of plant contain the same number of stamens Still used to the day (with some modifications) Did not anticipate the discovery of the vast number of living and extinct species Provided foundation on which modern biology built Not many 18-century inventions survive today 8 Binomial Nomenclature System of naming organisms based on a unique two-part name for each 1st part: Designates the genus (Generic name) 2nd Part: Designates the species (Specific epithet) Usually a word describing a quality of the plant 9 Binomial Nomenclature Rules Generic (1st part) can be used alone to designate all species in the genus Specific epithet (2nd Part) is never used alone First letter is always capitalized, second is not Both names must be underlined or italicized Zea mays 10 Specific Epithet Can be used in more than one genus Ex. Quercus alba, white oak No other oak species can have alba as an epithet Other species can have the same epithet Nymphaea alba, European white water lily; Salix alba, white willow 11 3rd Part of Scientific Name Citation of person who formally described organism Ex. Spiderwort Trandescatia virgiana Linnaeus → Trandescatia virgiana L. Draft Index for Author Abbreviations Resource for finding the name Useful in finding original description of particular plant 12 Why Latin? Scientific names generally come from Greek or Latin roots Or Latinized versions of persons, places, or characteristicis 13 (1) Precision to Avoid Confusion Acer saccharum, sugar maple tree Called different names in different regions of the US Mirabilis jalapa, four-o’clock Aka marvel-of-peru or beauty-of-the-night Important for accurate identification of organisms Limits confusion of names 14 (2) Universality Organisms only have one scientific name Some may have no common Allows researchers from all over the world to communicate with each other 15 Species is the Basic Unit of Classification Species One or more populations whose members can interbreed to produce fertile offspring but are reproductively isolated from other organisms Share a common evolutionary ancestry 16 Species is the Basic Unit of Classification 17 Species is the Basic Unit of Classification - Subspecies Not the smallest taxonomic group in use - subspecies Species able to interbreed Have certain characteristics that distinguish them from other populations of the same species Usually able to distinguish two subspecies Can get confusing especially at geographic range borders Interbreeding can occur Lead to reproductive isolation and evolution of a separate species Help with studying evolution 18 Species is the Basic Unit of Classification - Cultivars Plants that are produced by selective breeding Abbreviated form of cultivated variety Not equivalent to a subspecies Produced while under cultivation vs evolution by natural selection Nomenclature Used after scientific names Prunus persica cv. Rosea Prunus persica cv. Early Flame 19 Each taxonomic level is more general than the one below Remember: Classification is hierarchical Narrowest is species, broadest is the kingdom More general = broader & inclusive 20 Identification of Plants Primarily done on basis of structural features Dichotomous key Special guide that aids in identification Consists of a series of two contrasting statements made about plants Continues until organism is able to be identified 21 Identification of Plants 22 Systematics Classification of plants/organisms based on evolutionary relationships Based on common ancestry Phylogeny – evolutionary history Monophyletic – all plants within a taxonomic group Represent true evolutionary relationships Includes close relatives Polyphyletic – consisting of several evolutionary lines and not including common ancestor May misrepresent evolutionary relationships 23 Cladistics Emphasizes phylogeny by focusing on evolutionary lineages Use monophyletic and objective criteria to determine brank points Common ancestry is basis for classification 24 Cladistics 25 Questions Which of the following A) The scientific study of plant growth patterns and environmental interactions. best defines taxonomy in B) The classification and naming of the context of biological organisms based on shared sciences? characteristics and evolutionary history. C) The examination of the physiological processes and functions of living organisms. D) The analysis of genetic sequences to determine species relatedness. 26 Questions Which of the following sequences correctly lists the hierarchical ranks in the Linnaean classification system from the broadest to the most specific? A)Kingdom > Phylum > Class > Order > Family > Genus > Species B) Domain > Kingdom > Class > Order > Family > Genus > Species C) Kingdom > Order > Class > Family > Phylum > Genus > Species D) Domain > Phylum > Order > Family > Genus > Class > Species 27