Transcript Chapter 15
Chapter 15 Classification Systems 15-1 Why Classify? Why are classification systems useful? What are some characteristics of a good classification system? Why classify? Over 2.5 million kinds of species scientists have classified May be another 10 million or so unknown species still out there No one can keep track of these organisms by their names alone http://www.answers.com/topic/biodiversity Only way to study these organisms is divide them into smaller groups We have systems of biological classification that name and order organisms in a logical manner These systems have two important features 1. Assign a universally accepted name to each organism…Why? So scientists in other countries can know they are discussing the same organism 2. They place organisms into groups that have real biological meaning…Why? So they are in useful groups where they can expect the members to share important traits Dichotomous key style http://www.scholarsjunction.com/Taxonomy.aspx 15-2 Biological Classification One problem was that the names were too long and based off of physical characteristics of a species http://image.tutorvista.com/content/feed/tvcs/binomial-nomenclature-examples.jpeg Secondly, it was difficult to standardize names of organisms because different scientists chose different characteristics to describe http://fstoppers.com/wp-content/uploads/2013/05/photoshop-animals-together-new-species-18.jpg Carolus Linnaeus http://upload.wikimedia.org/wikipedia/commons/6/68/Carl_von_Linn%C3%A9.jpg Linnaeus Video Binomial nomenclature http://bio1151.nicerweb.com/Locked/media/ch26/26_04CarnivoraPhylogeny-L.jpg You give a two-part scientific name to the organism. The first name is the genus name and the second name is the species name http://images.tutorvista.com/content/modern-classification/human-being-and-hibiscus-systematic-position.jpeg They belong to that certain group http://www.glencoe.com/qe/images/b136/q4322/ch17_0_b.gif Their body structures they shared, taxa http://www.bio.miami.edu/~cmallery/150/physiol/c34x2chordates.jpg Taxonomy-The science of naming organisms and assigning them to these groups is called taxonomy http://cristinahenryclassification.weebly.com/uploads/1/1/0/2/11023925/8677203_orig.jpg Species-A population of organisms that share similar characteristics and that can breed with one another. http://www.glacierbayalaska.com/wp-content/uploads/2010/12/alaska-fish-species.jpg Kingdom, Phylum, Class, Order, Family, Genus, Species http://www.biologycorner.com/resources/orca_taxonomy.gif 15-3 Taxonomy Today How do taxa show evolutionary relationships among different organisms? How do modern scientific techniques contribute to the classification of organisms? Taxonomy Today Throughout the many years since Linnaeus, biological taxonomy has changed Species is the only level that has a clear biological identity (share common gene pool) Above species there can be many variations because different scientists believe that some characteristics are more important than others This causes organisms to be moved between taxa quite a bit http://www.nature.com/nature/journal/v438/n7069/fig_tab/nature04338_F10.html Taxonomy and Evolutionary Relationships Taxonomists tend to group organisms in ways that show evolutionary relationships They identify and study homologous structures, embryos and well-preserved fossils Species shown to be closely related are classified together Which structures are most important is up for debate Biochemical Taxonomy All forms of life share organic molecules that are almost, but not exactly, identical from species to species Taxonomists use this as a way to classify as well All forms of life use DNA which carries a common genetic code http://secularpsychedelic.webs.com/apps/photos/photo?photoid=122401939 Genes in many different organisms resemble one another due to the theory of common descent Similar genes direct the synthesis of similar proteins Cytochrome c is a protein used by almost every organism but it is slightly different between species They than compare the DNA sequences for cytochrome c between two species to see relation Cytochrome c http://en.wikipedia.org/wiki/Cytochrome_c 15-4 The Six-Kingdom System Linnaeus started with two kingdoms (vegetabile & animalia) and it is increased since then to 5/6 This increased by discoveries of such different organisms There are three domains Bacteria, Archaea, & Eukarya Make up six kingdoms bacteria, archaea, protista, plantae, fungi, animalia http://www.bioedonline.org/slides/slide01.cfm?q=%22archaebacteria%22&dpg=1 Bacteria Prokaryotic Some are aerobic and some are anaerobic Some are autotrophic and some are heterotrophic More abundant than any other organism (more abundant on your body than there are people in the world Bacteria http://cires.colorado.edu/news/press/2009/bodyBacteria.html Archaea More ancient than bacteria but more closely related to eukaryote ancestors Live an extreme environments (boiling hot springs, salty lakes, thermal vents, and in anaerobic conditions) http://www.microbiologyonline.org.uk/about-microbiology/introducing-microbes/archaea Protista Contains all the single-celled eukaryotic organisms There are animallike protists, plantlike protists, and funguslike protists Scientists believe that evolution came from these protists Amoeba http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20102/bio%20102%20lectures/protists/protists.htm Fungi Build cell walls that do not contain cellulose Heterotrophic and do not photosynthesize Do not always have separate cells divided by complete cell walls http://www.botanicalgarden.ubc.ca/potd/2006/10/fungus_diversity.php Plantae Muticellular, have cell walls that contain cellulose, and are autotrophic Includes all plants such as flowing plants, mosses, and ferns Also includes multicellular algae http://en.wikipedia.org/wiki/Plant Animalia Multicellular Heterotrophic, Have cell membranes without cell walls http://en.wikipedia.org/wiki/Animal