Topic 5.5

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Classification

Why Classify?1. How many

‘different sorts’ of living things are there on the planet?

How many species are there in the world?

Let’s start with some classification!

Take 5 minutes to write down ways in which we can classify the students in class todayKey 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’ categoriesA good classification system allows us to make generalisations AND organise our ideas about organismsClassification involves giving every organism an AGREED NAMEClassification involves arranging organisms into apparently related organisms

The American Robin

(Turdus Migratorius)

The European Robin

(Erithracus Rubecula)

What is taxonomy?

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 systemCladistics (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

CladisticsA taxonomic system based on common evolutionary ancestryThe Method of choice for classifying organisms, since it recognises and involves evolutionary theory

Developed since 1958Any 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 treeAn ‘Evolutionary Tree’Shows inferred evolutionary relationship among species based on similarities/differences in their genetic material or physical appearance

Linnaean ClassificationDeveloped by Carl LinneausSwedish botanist & taxonomistIs 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/watch?v=F38BmgPcZ_I

Binomial NomenclatureEach species is assigned a two part scientific name.Written in italics If handwritten, underline the nameFirst 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

classificationBiological taxonomy is hierarchicalAs 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)KingPhilipCame Over For GoodSpaghetti

From Kingdom…

From Kingdom…Linnaeus originally

divided living things into 2 (then 3) kingdoms…

AnimaliaVegetalia (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 AnimaliaEukaryoticMulticelluarHeterotrophicTerrestrial and aquaticSexual (a few are asexual)Motile (a few are non-motile)

Kingdom Plantae1. Eukaryote2. Multicellular3. Autotrophic4. Mostly terrestrial5. Sexual and asexual6. NonmotileMosses, Ferns,

flowering plants, conifers

Kingdom FungiEukaryoticHeterotrophicUnicellular and multicellularMainly terrestrialAsexual and sexualNon-motile

Mushrooms, puffballs, yeasts, rusts, water moulds

Kingdom prokaryotae (Monera)

ProkaryotesHeterotrophic and autotrophicAnaesrobic and aerobicAquatic, terrestrial and aerosolMostly asexualMostly non-motile (one kind are motile)

Kingdom Protoctistae (Protists)

EukaryotesHeterotrophic and autotrophicUnicellularMostly aquaticMostly asexualMotile and non-motile

Protozoa, slime moulds, algae

Brown Algae

…To SpeciesA 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 interbreedif 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 ClassificationStart 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.htmUse 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