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Phylogenetic trees & dichotomous keys

Classifying Life on Earth. Phylogenetic trees & dichotomous keys. Carolus Linnaeus developed the two-word naming system called binomial nomenclature. ex. Grizzly bear is called Ursus arctos . The first part of a name is the genus to which the organism belongs.

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Phylogenetic trees & dichotomous keys

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  1. Classifying Life on Earth Phylogenetic trees &dichotomous keys

  2. Carolus Linnaeus developed the two-word naming system called binomial nomenclature. • ex. Grizzly bear is called Ursusarctos. • The first part of a name is the genus to which the organism belongs. • A genus is a group of closely related species. • The second part of a name is unique to each species within a genus Binomial nomenclature

  3. Linnaeus’s hierarchical system of classification includes seven levels. From smallest to largest they are: species, genus, family, order, class, phylum, and kingdom. Linnaeus’s System of classification

  4. Evolutionary Family Trees Used to show how certain organisms evolved into other organisms As organisms change they branch away from ancestors Phylogenetic trees

  5. Phylogenetic trees usually connect all species to a common ancestor. What is the biggest evidence for a common ancestor? Common Ancestor

  6. At first, Aristotle said there were only Plants and Animals. • What was wrong with his system?

  7. Tolls used to help classify organisms based on yes/no questions • There are always 2 choices! That’s why it’s DI-chotomous Dichotomous Keys

  8. A Key to the leaves of some common trees of the northeastern USA 1 a. Leaves are evergreen, thin, needle-like…...………………………………………..……go to 2 b. Leaves are broad, deciduous……………...…………………………………….……..….....go to 6 2. a. Needles are over one inch long, in clusters…..………………………………........ go to 3 b. Needles are one half inch or less…………………………………………………..…..... go to 4 3. a. Needles in clusters of three……………..………............…….….Pitch pine (Pinusrigida) b. Needles in clusters of five……………..……………....… Eastern White Pine (Pinusstrobus) 4. a. Needles scale-like, sharp, cover twigs……..Eastern Red Cedar (Juniperusvirginiana) b. Needles protrude from the twigs…………..……………………………………….…… go to 5 5. a. Needles flat, rounded tips in 2 rows along twig…Eastern Hemlock (Tsugacanadensis) b. Needles in whorl around the stem………………..……….…White Spruce (Piceaglauca) 6. a. Compound leaves divided into 7 leaflets……………....White ash (Fraxinusamericana) b. Simple leaves…………………………………………………………………………..………….. go to 7 7. a. Lobed, rounded leaves with 7 to 9 lobes…….………...……….White Oak (Quercus alba) b. Toothed leaves……………………………………………………….…………………………... go to 8 8. a. Long slender leaves which droop down………....…………Weeping Willow (Salix babylonica) b. Leaves are less than twice as long as broad………………………….……….. go to 9 9. a. Leaves have an elliptical shape…………....…………………American Beech (Fagusgrandifolia) b. Leaves are toothed and lobed………….……..………………….Sugar Maple (Acer saccharum

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