The Science of Classification

1. The Science of Classification

2. Why do we need to be able to identify and classify organisms? • To avoid confusion surrounding common names • Eg. Puma, cougar, mountain lion, panther • Has more than 40 common names! • Only one scientific name: Felisconcolor Not what I mean!

3. What would you call this animal? • Groundhog • Woodchuck • Whistle pig • Forest marmot Marmotamonax

4. Why do we need to be able to identify and classify organisms? • Farmers and gardeners need to be able to identify weeds that might be competing with their crop plants

5. Why do we need to be able to identify and classify organisms? • Infections need to be identified so that the correct medicine is prescribed • E.g. bacterial infection vs. viral infection vs. fungal infection vs. parasitic protist or animal infection

6. Correct identification of plants for medicinal use is essential! Safe Poisonous!

7. Malaria – A Case for Classification • Malaria is caused by the parasitic protozoan (Kingdom Protista) Plasmodium and is transferred by mosquitoes into new hosts

8. Malaria – A Case for Classification • Early 1900s, insecticide use failed to control the spread of malaria • Close inspection of mosquitoes revealed several differences in banding patterns, food habits, and other behaviour Curse you scientists!

9. Malaria – A Case for Classification • Once the different types of mosquitoes were identified and classified, scientists discovered that differences in their physiology resulted in the insecticide killing the wrong types of mosquitoes; had to develop new insecticides • Insecticide impregnated mosquito netting for beds

10. Taxonomy – the science of naming, identifying, and classifying species • Carl Linnaeus (1707-1778) established the naming system binomial nomenclature • (Genus species) • grouped species into taxonomic ranks or levels according to shared morphological characteristics • Pros and cons (see handout) The “father” of taxonomy

11. Traditional Taxonomic Ranks of Classification

12. Dichotomous Keys • An identification tool used to help identify organisms, usually to the genus and species level • Poses a series of questions about an organism, and each question asks users to choose between two possible characteristics that the organism may have

14. Assignment: Whale Classification

15. Modern Classification of Species • Morphological Species Concept: anatomical similarities and differences • Biological Species Concept: ability to mate and produce fertile offspring • Phylogenetic Species Concept: evolutionary development of a group of organisms; examine evolutionary relationships among species to infer how closely related they are; can compare physiologies, biochemical similarities (e.g. proteins), DNA

16. Phylogenetic Trees • a diagram that shows the hypothesized evolutionary relationships between different species • The tips of the branches represent species (descendents). • Each node represents a common ancestor of the species above.

17. Clades • A CLADE is a taxonomic group that includes a single common ancestor and all its descendents How many clades are shown at left? above?

19. Assignment: • Using Phylogenetic Trees to Infer Evolutionary Relationships and to Identify Clades

20. Domains of Life • All organisms can be classified into three distinct groups called domains. These groups show distinct differences in their genetic makeup which is evidence of their distinct evolutionary kinships. The 3 Domains

21. 6 Kingdoms Kingdoms of Life

22. Assignment: • Complete the Kingdom comparison chart using your textbook as a reference. • Answer text questions.