Topic 5.5 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 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)

What is taxonomy?

Taxonomy is the process of (scientific) classification Taxis: Greek for ‘Arrangement or Division’ ‘Nomos’: Greek for ‘Method or Law 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. 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

How is Life Classified? Pre-1969: Life is classified into 2 Kingdoms: Plantae and Animals 1969 – 1999: Life is classified into 5 Kingdoms: Monera, Protista, Plantae, Fungi, Animalia: using Linnaean Classification System – based on anatomy, morphology, embryology and cell structure BUT: The Traditional 5 kingdom System does not explain how kingdoms may be related through evolutionary relationships among the kingdoms

The Three Domains Karl Woese discovery of Archae

The 3 domains were proposed by Dr Karl Woese Dogma The eukaryote-prokaryote dichotomy was the central dogma of biology. Woese was making a claim of extraordinary scope. He was saying that we had missed one-third of all living things. People did not like that (5). "I hadn't been trained as a microbiologist, so I didn't have this bias" [about impossibility of bacterial classification]. (Woese)

Classification is a ‘messy’ branch of science… Just compare the University of Oxford and the University of Berkeley…

Oxford University Museum of Natural History 5 Kingdoms: one prokaryotic, four eukaryotic

University of California Berkeley

Classification in the Animal Kingdom

Kingdom Animalia Contains organisms as diverse as coral and mice….

Classification in the Plant Kingdom

Plant Classification (UMCB)

From Kingdom… 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)

Kingdom Plantae 1. Eukaryote 2. Multicellular 3. Autotrophic 4. Mostly terrestrial 5. Sexual and asexual 6. Nonmotile Mosses, Ferns, flowering plants, conifers

Kingdom Fungi Eukaryotic Heterotrophic Unicellular and multicellular Mainly terrestrial Asexual and sexual Non-motile Mushrooms, puffballs, yeasts, rusts, water moulds

Kingdom prokaryotae (Monera) Prokaryotes Heterotrophic and autotrophic Anaesrobic and aerobic Aquatic, terrestrial and aerosol Mostly asexual Mostly non-motile (one kind are motile)

Kingdom Protoctistae (Protists) Eukaryotes Heterotrophic and autotrophic Unicellular Mostly aquatic Mostly asexual Motile and non-motile Protozoa, slime moulds, algae Brown Algae

…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)

Test yourself

Classification of the malaria parasite, Plasmodium falciparum Kingdom Protista (Subkingdom) Protozoa Phylum: Apicomplexa Class: Sporozoasida Order: Eucoccidiorida Family: Plasmodiidae Genus : Plasmodium Species : falciparum, malariae, ovale, vivax

Classification of the malaria vector: Aedes Aegyptae Kingdom : Animalia Phylum : Arthropoda Class : Insecta Order : Diptera Family : Culicidae Subfamily : Culicinae Genus : Aedes Species : Aegyptae

Now your turn : IB Classification Requirements 5.5.2: List seven different levels in the hierarchy of taxa: kingdom, phylum, class, order, family, genus and species, using an example from two different kingdoms for each level Scenic Oregon Hierarchical Classification Use the Scenic Oregon I-animal website to write information about an animal of your choice Use the University of Berkeley Website to write information about a plant species of your choice

5.5.3 Distinguish between the following phyla of plants, using simple external recognition features Resources: Clegg, P. 165 – 168 Evolution Drop-down menu in the Blog has resources on all major plant phyla

5.5.4 Distinguish between the following phyla of animals, using simple external recognition features: porifera, cnidaria, platyhelminths, annelida, mollusca and arthropoda Resources: Clegg, P. 165 – 168 Evolution Drop-down menu in the Blog has resources on all major invertebrate phyla

Classification of the Kingdoms: Synonyms One prokaryote kingdom Bacteria Monera No nucleus Divide by binary fission (asexual) Four eukaryote Kingdoms Protoctista Fungi Plantae Animalia

Dichotomous Keys

From classification to dichotomous keys… Classification and identification go hand in hand. Once identified, organisms can be classified by placing them in groups that have similar characteristics. To determine the scientific name of an organism, taxonomists use a process of elimination, called keying, to assist them. A dichotomous key is constructed so that pairs of contrasting characteristics are set up in a precise sequence. Each step in the identification process involves the selection of a characteristic from each pair.

Now try some yourselves… Dichotomous keys trees of oregon Florida Keys Flowers life.html Simple Tree dichotomous key

Wednesday/ Thursday Starting on Topic G3: Impacts of Communities on Ecosystems