Taxonomy Notes Nowicki Biology, Chapter 17

17.1: The Linnaean System of Classification Linnaeus developed the scientific naming system still used today taxonomy – science of naming and classifying organisms hierarchical – multilevel scale in which each level is contained or included in every level above it based on the system developed by Carolus Linneaus 1707-1778

17.1: The Linnaean System of Classification Taxonomy- Discipline of classifying organisms and assigning each organism a universally accepted name. Why classify? Classification makes life easier. What are some ways we classify?

17.1: The Linnaean System of Classification Looking at the Figure 1: Animal Hierarchy: Dogs are _____________ and _________________ Are birds animals? ______ Are fish mammals? _____ Mammals Animals yes no

taxon – a level of classification; the basic level is species; taxa is the plural the diagram below shows 8 taxa in the hierarchical system of classification we use most general/least specific (includes the greatest number of organisms most specific - contains only one single kind of organism

Mnemonic (Dear King Phillip Came Over For Grape Soda) =Domain =Kingdom =Phylum =Class =Order =Family =Genus =Species Did King Philip Come Over For Great Spaghetti? Make your own mnemonic & share with the class! Retrieved November 7, 2012 from: http://t0.gstatic.com/images?q=tbn:ANd9GcStUGGM6A4zpDe9XdIYi5YPTQrwXChoO9OE7t1jckDACHcO3xMu Retrieved November 7, 2012 from: http://t2.gstatic.com/images?q=tbn:ANd9GcT3qsTkcIf39fQlexaQnJ91c2o7a6MoQVLkixdDJXxpg3p67mA9

17.1: The Linnaean System of Classification (Domain is not shown in the diagram to the left) When looking at the taxonomic hierarchy (Domain, Kingdom, etc), Which taxon has the most diverse group of organisms? Kingdom Animalia Which taxon is the least diverse? Species (Dendroica fusca)

17.1: The Linnaean System of Classification Scientific Naming Using common names is confusing because many organisms may have several different common names. The cougar is also known as the mountain lion, puma or catamount, thus the need for a scientific name. We use binomial nomenclature to assign scientific names. The scientific name for a cougar is Felis concolor

17.1: The Linnaean System of Classification binomial nomenclature – a system of naming in which each species has a two-part scientific name Two different species cannot have the same scientific name Importance? Binomial nomenclature provides a standard of communication among biologists, regardless of their native language

17.1: The Linnaean System of Classification scientific name – genus and species names of an organism - basis for our system of naming organisms. - two parts: o genus – first part/word of the scientific name always capitalized and italicized (typing) or underlined (handwriting) can be used alone Homo sapiens Ursus arctos

17.1: The Linnaean System of Classification o species – second part/word of the scientific name never capitalized always italicized (typing) or underlined (handwriting) can never be used alone Homo sapiens Ursus arctos

Scientific Names

Helix pomatia Vespula germanica What do these names all have in common? Helix pomatia Vespula germanica Carcharodon carcharias Crocodylus acutus Capitalized & Italicized

What do these all have in common? When Written: What do these all have in common? Capitalized → ←underlined

Scientific Names EXAMPLE: One of the most commonly used scientific names is Escherichia coli. This is the scientific name of a rod-shaped bacteria that lives in your intestines, helping you digest your food and produce vitamin K (necessary for blood clotting). It is also used in research involving bacteria and is sometimes linked to outbreaks of food-poisoning. When the name has been typed, it should look like this: Escherichia coli When the name has been handwritten, it should look like this: It is okay to abbreviate the full name like this: E. coli or Escherichia, but never like this: coli Why are all scientific names so weird? Why can’t they just be “in English”? Scientific names are written in Latin because it is not a language spoken in any country today; therefore, it is a nonpolitical choice. There are several divisions of the International Code of Nomenlature that govern the naming of all organisms.

examples of scientific names - named after people (ashei named after botanist Ashe), named after location (Lupinus texensis), and characteristics (Mimus polyglottos - mimics many voices), cornutum - crown, novemcinctus - 9 belts,

The Linnaean classification system has limitations Linnaeus based his classification on physical similarities today we have technology that allows us to look at molecular similarities (amino acid sequences in proteins that are based on nucleotide sequences in the genes of the DNA) remember that organisms can look similar due to analogous characteristics resulting from convergent evolution (think back to evolution: bird wings and butterfly wings have the same function, different structure) classification should be based on homologous characteristics resulting from divergent evolution (think back to evolution: homologous characteristics share the same structure, have a common ancestor but have a different function) molecular homology is much more definitive in determining species relationships than physical analogy

17.1: The Linnaean System of Classification The more taxonomic levels that two organisms share, the more closely related they are. Which bears are most closely related? The shared genus name Ursus indicates that the grizzly bear and polar bear are more closely related. The panda bear is more distantly related because it does not belong to the same genus as the other two. Ursus maritimus Ursus arctos Ailuropoda melanoleuca Pictures reproduced with permission from WWF. © 2004 WWF- World Wide Fund For Nature (Formerly World Wildlife Fund). All Rights Reserved. www.panda.org.

THINKING CRITICALLY Kingdom Phylum Class Order Family Genus Species Organism Cat Wolf Fly Kingdom Animalia Phylum Chordata Arthropoda Class Mammalia Insecta Order Carnivora Diptera Family Felidae Canidae Muscidae Genus Felis Canis Musca Species F. domesticus C. lupus M. domestica Have students study this chart. The next slide lists three questions to answer using this chart. You may have to advance to the next slide, let students read the question and then come back to the chart so they can find the answer.

Use the chart Using the chart on the previous slide and your notes 1. What type of animal is Musca domestica? Animal; insect 2. From the table, which 2 animals are most closely related? Cat and Wolf 3. At what classification level does the evolutionary relationship between cats and wolves diverge (become different)? Family Level

dichotomous key – tool used by scientists to identify organisms in the field based on defining characteristics arranged in pairs of questions to which the answer is generally yes or no, followed by a direction of what pair of questions to go to next until the organism has been identified key to using this tool is always starting with the first pair of questions!

Dichotomous Key Norns are a very rare and actually imaginary animals that belong to the genus Norno. There are 8 different species of Norno, generally located in specific regions of the world. Use the key to identify the Norns shown. A = kentuckyus B = californius C = walawala

17.2: Classification Based on Evolutionary Relationships phylogeny – evolutionary history for a group of species can be shown as branching “family trees” think back to evolution and phylogenetic trees: does this reflect convergent or divergent evolution? Divergent

17.2: Classification Based on Evolutionary Relationships Cladistics is classification based on common ancestry. cladistics – classification based on common ancestry goal is to place species in the order in which they descended from a common ancestor cladogram – diagram based on patterns of shared, derived traits that shows the evolutionary relationships between groups of organisms clade – group of species that share a common ancestor

17.2: Classification Based on Evolutionary Relationships derived characters – traits that can be used to figure out evolutionary relationships among a group of species; traits are shared by some species but are not present in others the more closely related species are, the more derived characters they will share outgroup – group of species that shares no derived characters with the other groups being studied

Cladogram 1. Which are the derived characters in the cladogram below? 2. Circle the Hagfish and label it, “outgroup.” Explain why it’s the outgroup.

17.2: Classification Based on Evolutionary Relationships Complete Quicklab: Classifying – Construct a Cladogram, p. 511

17.2: Classification Based on Evolutionary Relationships Cladograms are important tools in classification because they represent true evolutionary relationships based on all available data, especially molecular homology--DNA &/or amino acids.

What derived traits do groupers have? jaw bones, vertebral column Do Lancelets contain a vertebral column? no What organism is closely related to the wolf? turtle

17.3: Molecular Clocks Molecular clocks use mutations to estimate evolutionary time molecular clocks – models that use mutation rates to measure evolutionary time basis for using molecular data to determine relatedness of 2 organisms o more differences between the genes or proteins of 2 organisms means they are more distantly related they are (they shared a common ancestor a long, long time ago) o fewer differences between the genes or proteins of 2 organisms means they are more closely related (they shared a common ancestor more recently)

(Read pages 516-518 for more information on Molecular Clocks)

17.4: Domains and Kingdoms Eubacteria Archaea Eukarya

17.4: Domains and Kingdoms The three domains in the tree of life are Bacteria, Archaea, and Eukarya Bacteria – includes single-celled prokaryotes in the kingdom Bacteria cell wall contains peptidoglycan includes bacteria that live in/on organisms, soil decomposers, disease causing bacteria (everyday bacteria) Archaea – includes single-celled prokaryotes in the kingdom Archaea cell wall does not contain peptidoglycan, has lipids includes bacteria that live in extreme environments such as deep sea vents, hot geysers, salt lakes, etc. classifying Bacteria and Archaea is difficult because they so frequently transfer genes among themselves that defining a “species” is nearly impossible; this process is just beginning and will continue as we learn more about these organisms

17.4: Domains and Kingdoms Eukarya – made up of all organisms with eukaryotic cells – distinct nucleus and membrane-bound organelles can be single-cells, colonial, or multicellular includes the kingdoms Protista, Plantae, Fungi, and Animalia