Let’s start with some classification! Take 5 minutes to write down ways in which we can classify the students in class today Key features of a classification key are that it must be clear, consistent, and easily implemented
Why Classify? In order to sort out and compare living things, we need to organise them into ‘manageable’ categories A good classification system allows us to make generalisations AND organise our ideas about organisms Classification involves giving every organism an AGREED NAME Classification involves arranging organisms into apparently related organisms
The American Robin (Turdus Migratorius) The European Robin (Erithracus Rubecula)
Taxonomy is the process of (scientific) classification Taxis: Greek for ‘Arrangement or Division’ ‘Nomos’: Greek for ‘Method or Law http://www.youtube.com/watch? v=F38BmgPcZ_I
Systems used to classify living organisms Linnaean Binomial Nomenclature system Cladistics ( Ancient Greek –Branch ) Phylogenetics
The evolution of taxonomy… The Linnaean classification system was created long before scientists understood that organisms evolved. Because the Linnaean system is based on morphology (form and structure) rather than on evolutionary theory Most biologists are switching to a classification system that reflects the organisms' evolutionary history Phylogenetic tree Cladogram
Cladistics A taxonomic system based on common evolutionary ancestry The Method of choice for classifying organisms, since it recognises and involves evolutionary theory Developed since 1958 Any group of organisms are related by descent from a common ancestor. There is a bifurcating pattern of cladogenesis. Change in characteristics occurs in lineages over time. Cladistics introduction
Phylogenetic tree An ‘Evolutionary Tree’ Shows inferred evolutionary relationship among species based on similarities/differences in their genetic material or physical appearance
Linnaean Classification Developed by Carl Linneaus Swedish botanist & taxonomist Is still used today, basis for classification and naming of all new species. Based on physical traits, most of his classifications are still accurate. http://www.youtube.com/watc h?v=F38BmgPcZ_I
Binomial Nomenclature Each species is assigned a two part scientific name. Written in italics If handwritten, underline the name First word is capitalized (Genus): NOUN Second word is lowercase (Species): ADJECTIVE
Binomial Nomenclature Homo sapiens Modern human Hawksbill Turtle ( imbricate: arrange so that they overlap like tiles) Genus species The genus name can be abbreviated if you have already used the full name in your text Eretmochelys imbricata
Linnaeus also defined four groups of humans, and the divisions were based on both physical and social traits. By 21st-century standards, his descriptions can be regarded as racist. How does the social context of scientific work affect the methods and findings of research? Is it necessary to consider the social context when evaluating ethical aspects of knowledge claims?
There are seven (err, actually 8) levels of classification Biological taxonomy is hierarchical As we move from kingdom (domain) to phylum, all the way to species, organisms share more and more characteristics. This system allows us to group organisms while also assigning unique species names.
(Domain) K ing P hilip C ame O ver F or G ood S paghetti
Linnaeus originally divided living things into 2 (then 3) kingdoms… Animalia Vegetalia (Plants) Mineralia (Minerals, since abandoned) We now widely recognise FIVE kingdoms: 1. Kingdom Plantae (the plants) 2. Kingdom Animalia (the animals) 3. Kingdom Fungi (the fungi and moulds) 4. Kingdom Protocista (protozoa and alga) 5. Kingdom Prokaryote [Monera] (the euBacteria and archebacteria)
Kingdom Animalia Eukaryotic Multicelluar Heterotrophic Terrestrial and aquatic Sexual (a few are asexual) Motile (a few are non- motile)
…To Species A group of organisms which can interbreed and produce fertile offspring. Species are named: Genus species Heliconius charithonius The smallest taxonomic group, though many subspecies are recognized. Might potentially interbreed if a barrier or other challenge was removed (ie: distance)
5.5.3 Distinguish between the following phyla of plants, using simple external recognition features: bryophyta, filicinophyta, coniferophyta and angiospermophyta.
5.5.4 Distinguish between the following phyla of animals, using simple external recognition features: porifera, cnidaria, platyhelminths, annelida, mollusca and arthropoda.
Now…Action! Go to Mr T@s slideshow in Classification Start on Slide 14 (use the buttons at the bottom of the viewer to navigate). By clicking on each picture you can link to information about each type of plant. Slide 15: Make this table in your notebook. Slide 15: Fill in this table. If you're not sure what is meant by sporangia, look it up! Don't simply write things down if you don't understand them. You can also click back to slide 14 click on the image of the plant type to get more information.
For tomorrow… http://www.scenicoregon.com/webanic/play.htm Use the Scenic Oregon I-animal website to write information about each specific animal phylum. You don’t need to prepare information about each class. You will be sharing your information in class tomorrow