1. Taxonomy The science of naming organisms.

2. Aristotle 2000 years ago – only 1000 or so organisms had been “discovered” Classification system developed by Aristotle consisted of: PLANT ANIMAL - woody stems- motile (move) - non-woody stems- sessile (can’t move)

3. What are the levels of biological organization?

4. Biotic OR Abiotic?

5. Carolus Linnaeus Described organisms with two word names – all in Latin (why?) Developed binomial nomenclature First word = genus name (upper case) Second word = species name (lower case)

6. Why binomial nomenclature? Much easier than a 10+ word name under old “polynomial system” Same name no matter where you go Less confusion – same language throughout the world (Latin) Binomial = SCIENTIFIC NAME

7. Do you know what these animals are? Homo sapiens - Canis lupus – Canis lantrans - Felis domesticus - Pan troglodytes – Ursus arctos – Equus caballus- Turdus migratorius – Orcinus orca -

8. Do you know what these animals are? Homo sapiens - human Canis lupus – wolf Canis lantrans - coyote Felis domesticus - house cat Pan troglodytes – chimpanzee Ursus arctos – grizzly bear Equus caballus- horse Turdus migratorius - robin Orcinus orca - killer whale

9. Taxonomic hierarchy Names organisms and their relationships from very broad (ie includes a lot of organisms in a variety of categories) to very specific (ie includes much fewer organisms with fewer diversifying traits)

10. All organisms classified in a hierarchy Domain (broadest) Kingdom Phylum Class Order Family Genus Species (most specific) Danish King Phillip Came Over For Green Spinach

11. 3 domains of life EUKARYA BACTERIA ARCHAEA

12. Classify a human and a bobcat: GROUPHUMAN BOBCAT Domaineukarya eukarya Kingdomanimalia animalia Phylumchordata chordata Classmammalia mammalia Orderprimates carnivora Familyhominidae felidae GenusHomo Lynx Speciessapien rufus

15. What is a species anyway? Biological species concept –A group of actually or potentially breeding natural groups that are reproductively isolated from other groups. »Ernst Mayr, 1924 Extended definition of species to include: –Hybrids Sterile offspring of two different species

16. How many are out there? Scientists currently estimate that –There are 10 million species worldwide –Over 5 million live in the tropics –Most unnamed species are small or microscopic

17. Why is taxonomy useful? Helps prevent confusion among scientists Helps to show how organisms are related Can be used to reconstruct phylogenies – evolutionary histories – of an organism or group

18. A note on cladograms Graph showing when different groups diverged from a common ancestral line Points where they diverge are often noted with a feature that was different between ancestral group and a “new” feature in the group that split off.

19. Bird Cladogram

20. Dichotomous Key A dichotomous key is a device that can be used to easily identify an unknown organism. The word dichotomous comes from two Greek words that together mean, "divided in two parts". A dichotomous key consists of a series of two part statements that describe characteristic of organisms. At each step of a dichotomous key the user is presented with two choices. As the user makes a choice about a particular characteristic of an organism they are led to a new branch of the key. Eventually the user will be led to the name of the organism that they are trying to identify. Saskatchewan Education. (1992) Science: A Curriculum Guide for the Secondary Level Biology 20/30. Saskatchewan Education. p. 106

21. For example: Construct a dichotomous key with a few school supply items:

22. When constructing a dichotomous key, the first step is to look at the group of objects or organisms and separate them into two groups based on a single distinguishing characteristic. Then continue to separate each of the groups until each object has its own separate set of characteristics. Arrange the items in a “spider key” before putting them into the traditional dichotomous key format.

23. SPIDER KEY

24. DICHOTOMOUS KEY