Name ___________________________________ Period _______________

Worksheet D -- Taxonomic Key

A taxonomic key is a tools used to identify and classify organisms. Most keys consist of a setof paired statements describing a certain trait. By choosing from a series of these paired traits, abiologist can place an unknown organism in smaller and smaller groups until the organism iseither identified or proved to be something new.Use the following key to identify the leaves on the next page. Write the steps used and thescientific and common name of each tree in the spaces provided. (use the leaf terms at thebottom of the leaf page to help)

1a. Leaves needlelike: Go to 21b. Leaves broad with flattened surface or blade: Go to 6

2a. Needles up to 2.5 cm long: yew, Taxus canadenis2b. Needles 5.0 cm or longer: Go to 3

3a. Needles 5.0 to 12.5 cm long: Go to 43b. Needles more than 12.5 cm long: Go to 5

4a. Needles in cluster of two: Scotch pine, Pinus sylvestris4b. Needles in clusters of four or five: white pine, Pinus strobus

5a. Needles in clusters of two: black pine, Pinus nigra5b. Needles in clusters of three: ponderosa pine, Pinus ponderosa

6a. Leaves divided into separate leaflets or little leaves: Go to 76b. Leaves all in one piece; no leaflets: Go to 8

7a. Leaves with five to seven leaflets, bottom pair smallest: shagbark hickory, Carya ovata7b. Leaves with thirteen to forty one leaflets: tree of heaven, Ailantbus altissima

8a. Leaf edge smooth, no saw-teeth: flowering dogwood, Cornus florida8b. Leaves saw-toothed or lobed: Go to 9

9a. Leaves saw-toothed, veins like barbs on a feather: beech, Fagus grandifolia9b. Leaves three to five lobes, veins radiate from a central point: sugar maple, Acer saccharum

Name ______________________________________ Period _______________

A. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

B. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

C. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

D. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

E. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

F. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

G. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

H. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

I. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

J. steps _____, _____, _____, _____, _____, _____, _____, _______common name ___________________________________scientific name __________________________________

Answer the following questions in complete sentences:

1. Why do scientists classify organisms? _____________________________________

______________________________________________________________________

2. How do you write a correctly punctuated scientific name?_______________________

______________________________________________________________________

3. Why don't we just use the English or common name for organisms in science? ______

_______________________________________________________________________

4. Look at the leaves you classified. What are three leaf traits or characteristics you used toclassify the leaves?

1, _________________________________________________________________

2. ________________________________________________________________

3. _______________________________________________________________

Leaf terms: