Taxonomic Systems

Taxonomic Systems By:Seaneen Richard

The Big Bang Theory • Sheldon’s taxonomic approach to friendship! http://www.youtube.com/watch?v=k0xgjUhEG3U&list=PLzF87B-rWu6j3XXxDp-cWBgfrdx9r6X_v

Today’s Agenda • Curriculum expectations. • What is taxonomy? A brief history. • Binomial nomenclature. • Taxonomic systems and levels of classification. • Dichotomous keys. • Wrap it up.

Curriculum Expectations SB13U: Grade 11U biology Overall Expectation: • B3. demonstrate an understanding of the diversity of living organisms in terms of the principles of taxonomy and phylogeny. Specific Expectation: • B3.1. to explain the fundamental principles of taxonomy and phylogeny by defining concepts of taxonomic rank and relationship, such as genus, species, and taxon.

What is Taxonomy? • Taxonomy is the science of classifying organisms. 2 Main purposes of taxonomy; • To identify organisms. • To represent relationships among them. • Most taxonomists use a hierarchical system known as classificationto arrive at this conclusion.

The History of Taxonomy • Our present system of classification was developed by a Swedish botanist named Carl Linnaeus but it dates back to Aristotle. • He was the first to create rules for assigning names to plants and animals known as binomial nomenclature; a method that provides organisms with a 2 part scientific (Latin or Greek) name. • The two components that comprise an organisms scientific name are known as; • The scientific genus name. • The species name.

Rules of Binomial Nomenclature Genus name • The first letter is ALWAYS capitalized with the remaining part of the name in lower case. • Often based on some characteristic of the organism such as colour or habitat. Species name • The second part of the name and is all lower case. • Often describes similar characteristics of organisms within the same species. (i.e. physical features) Note: the complete scientific name must be italicized, however if this is not possible then the full name must be underlined. Genus name + species name = Scientific name

Levels of Classification • Our present classification system is comprised of 7 main levels of taxa(singular: taxon) (Note: the level is a taxon) • Every organism can be classified into 7 different taxa. Mnemonic: King Philip Came Over For Green Socks Activity

Levels of Classification • Each taxon contains organisms with similar characteristics and various groups within their level. • Each successive taxon contains fewer organisms, but the organisms become more similar in their characteristics. • Kingdom is the largest taxon and is very broad. There are six different kingdoms. • Species is the smallest taxon and is very narrow. Organisms within a species are able to mate and produce fertile offspring.

Kingdom • The highest taxon in the traditional Linnaean system of classification is the kingdom. • At this taxon, organisms are distinguished on the basis of cellular organization and methods of nutrition. • Whether they are single- or multiple-celled and whether they absorb, ingest, or produce food are critical factors. • Based on these types of distinctions, the scientists have distinguished between six kingdoms of living things Activity

The Six Kingdoms

Taxonomy Video and Handout • http://www.youtube.com/watch?v=F38BmgPcZ_I&list=PLRSXRcjfK6cBeGaIxcUlq43YM9B-7ciZR • Taxonomy student handout copy.docx • When using the video and handout often students tune out. • To minimize this and sustain their attention use a resource like this but inform them that their future test will have questions taken directly from this video. This will help them to focus. • Things to consider: If you opt to use questions from the video, ensure the students have the content that you intend on using and also provide them with the link to the video for future studying purposes. Activity

The History of Domains • The Kingdoms grew from two to five thanks to scientist Robert Whittaker who proposed a five kingdom classification system consisting of; animalia, plantae, fungi, protista, and monera. • In the 1970’s microbiologist Carl Woese and other researchers at the University of Illinois conducted studies indicating that a group of prokaryotic microorganisms called archaebacteria were sufficiently distinct from bacteria and other monerans. • As a result they proposed that the Kingdom Monera be divided into two separate Kingdoms known as archaebacteria and eubacteria thus leading to the currently recognized six kingdoms.

The Story of the Three Domains In the beginning Protista Plantae Animalia Monera Fungi

The Story of the Three Domains Eubacteria Archaebacteria

The Three Domains

Phylogenic Trees • Most scientists believe that organisms have changed over time. • Phylogeny is the history of the evolution of organisms. • These relationships are often shown in a type of diagram called a phylogenetic tree. • A phylogenic tree starts from the most ancestral form and includes branching's that lead to all of its descendants.

Dichotomous Keys • Many scientists regularly use classification manuals to conduct their identification work. Usually it involves the use of a dichotomous key. • The key is constructed so that a series of choices must be made which can be answered with a simple yes or no. • Each answer leads to a new branch of the key. If choices are made accurately, the end result is the name of the organism being identified.

Sample Dichotomous Keys Things to Remember: 1) Keep the descriptions simple. 2) Work with one sub-group at a time. 3) Make sure your number correspond to your descriptions! Activity

Sample Homework

Wrap it Up • KOOSH BALL GAME • Taxonomy Koosh Ball wrap it up.notebook Activity

Taxonomic Systems