Unit 9: Classification

TARGETS  I can create a dichotomous key to classify and identify an organism.  I can use a dichotomous key to identify an organism.  I can create and interpret a cladogram (evolutionary chart) to see relationships between organisms.  I can explain why a two part naming system is important in classifying organisms.

Earth’s great diversity Scientists have identified 1.5 million species but have estimated that there are anywhere between 2 and 100 million additional species yet to be discovered!

With so much diversity, organisms must be classified Taxonomy – a discipline that scientists use to classify organisms and assign each organism a universally accepted name. Why is this important?

What animal is this?

cougar? Puma? Panther? Mountain lion? All of the above? These are all common names for this organism. This can create confusion for obvious reasons.

Binomial Nomenclature Carolus Linnaeus, a Swedish botanist, developed a two-word naming system called bionomial nomenclature. Carolus Linnaeus - bionomial nomenclature. Name is always in italics with the first name capitalized and the second lower case. Ex: grizzly bear (common name) Ursus arctos (scientific name) genusspecies

Linnaeus’s System of Classification Includes seven levels, or taxon or taxonomic category. From smallest to largest- Kingdom Phylum Class Order Family Genus Species Keep Pond Clean Or Froggy Gets Sick Kids Prefer Candy Over Fresh Green Spinach King Phillip Came Over For Grape Soda

Keep Pond Clean Or Froggy Gets Sick ingdomingdom hylumhylum lasslass amilyamily enusenus peciespecies Come up with your own acronym to help remember Linnaeus’s classification system rderrder

Same family

Evolutionary Classification Biologists now group organisms into categories that represent lines of evolutionary descent, or phylogeny, not just physical similarities. All members of a genus share a recent common ancestor. All genera in a family share a recent common ancestor. The higher the level of taxon, the farther back in time is the common ancestor

Cladistic analysis Considers only those characteristics of organisms that are new characteristics. Characteristics that appear in recent parts of a lineage but not in its older members are called derived characters. Derived characters are used to construct a cladogram- diagram that shows the evolutionary relationships of organisms.

Draw in your notes - Cladogram

1.Which traits does a Kangaroo have, that a shark does not have? 2.What traits does a shark have? 3.Is a bullfrog more or less related to a human than the shark? 4.What organism is most closely related to the human? How do you know? 5.What organisms have a vertebrae?

1.Which traits does a Kangaroo have, that a shark does not have? All of the traits that come after the shark branch, two pairs of limbs, mammary glands, placenta 2.What traits does a shark have? Vertebrae 3.Is a bullfrog more or less related to a human than the shark? A bullfrog is more related to a human than a shark is because it is closer in evolutionary ancestry 4.What organism is most closely related to the human? How do you know? The kangaroo is most closely related to the human because they share derived characteristics 5.What organisms have a vertebrae? All of them, shark, bullfrog, kangaroo, human

Creating a Cladogram 1.The organism that has the highest number of traits goes on the far right 2.Organism that has the fewest traits goes on the left 3.Continue to put the organisms in that order

Creating a Cladogram 4. After the organisms are in order, include the derived characters

Dichotomous Key Tool used to identify unfamiliar organisms. A dichotomous key is a series of paired statements that describe physical characteristics of different organisms.

CanaryOyster

Ants and flies have 6 legs!

TARGETS I can create a dichotomous key to classify and identify an organism. I can use a dichotomous key to identify an organism. I can create and interpret a cladogram (evolutionary chart) to see relationships between organisms. I can explain why a two part naming system is important in classifying organisms.

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