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
http://en.wikipedia.org/wiki/Cytochrome_c
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
http://cires.colorado.edu/news/press/2009/bodyBacteria.html
Bacteria
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
Multicellular Heterotrophic,
Animalia
Have cell membranes without cell walls
http://en.wikipedia.org/wiki/Animal