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Identifying Organisms. Dichotomous Key. What: A dichotomous key is a series of questions, each with only two answers. Who: Scientists Where: All over the World When: If you need to identify an unknown organism Why: To help identify an organisms genus and species. Field Guide.
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Dichotomous Key What: A dichotomous key is a series of questions, each with only two answers. Who: Scientists Where: All over the World When: If you need to identify an unknown organism Why: To help identify an organisms genus and species
Field Guide What: A book using pictures and descriptions to help identify organisms. Who: Anyone Where: All over the World When: If you need to identify an organism, and know exactly what it looks like Why: To identify the name of an organism
Field Guide and a Dichotomous Key Field guides are very different than dichotomous keys. For example, field guides use pictures and dichotomous keys use questions to identify an organism. Field guides are harder to use because you have to decide which organism throughout the whole book looks exactly like the one you are trying to identify.
Dichotomous Key or Field Guide? 1 a. Leaves are evergreen, thin, needle-like…………...………..2 b. Leaves are broad, deciduous……………...…………..6 2. a. Needles are over one inch long, in clusters…………..……3 b. Needles are one half inch or less………………………..4 3. a. Needles in clusters of three………….Pitch pine (Pinus rigida) b. Needles in clusters of five…… Eastern White Pine (Pinus strobus) 4. a. Needles scale-like, sharp, cover twigs....Eastern Red Cedar (Juniperus virginiana) b. Needles protrude from the twigs………………………5 5. a. Needles flat, rounded tips in two rows along twig….Eastern Hemlock (Tsuga canadensis) b. Needles in whorl around the stem…...……White Spruce (Picea glauca) 6. a. Compound leaves divided into 7 leaflet…....White ash (Fraxinus americana) b. Simple leaves.………………………………..7 7. a. Lobed, rounded leaves with 7 to 9 lobes…...…..White Oak (Quercus alba) b. Toothed leaves……………………………….8 8. a. Long slender leaves which droop down....…Weeping Willow (Salix babylonica) b. Leaves are less than twice as long as broad………………..9 9. a. Leaves have an elliptical shape………American Beech (Fagus grandifolia) b. Leaves are toothed and lobed…..………Sugar Maple (Acer Saccharum)
If you said Dichotomous Key, you were right!! 1 a. Leaves are evergreen, thin, needle-like…………...………..2 b. Leaves are broad, deciduous……………...…………..6 2. a. Needles are over one inch long, in clusters…………..……3 b. Needles are one half inch or less………………………..4 3. a. Needles in clusters of three………….Pitch pine (Pinus rigida) b. Needles in clusters of five…… Eastern White Pine (Pinus strobus) 4. a. Needles scale-like, sharp, cover twigs....Eastern Red Cedar (Juniperus virginiana) b. Needles protrude from the twigs………………………5 5. a. Needles flat, rounded tips in two rows along twig….Eastern Hemlock (Tsuga canadensis) b. Needles in whorl around the stem…...……White Spruce (Picea glauca) 6. a. Compound leaves divided into 7 leaflet…....White ash (Fraxinus americana) b. Simple leaves.………………………………..7 7. a. Lobed, rounded leaves with 7 to 9 lobes…...…..White Oak (Quercus alba) b. Toothed leaves……………………………….8 8. a. Long slender leaves which droop down....…Weeping Willow (Salix babylonica) b. Leaves are less than twice as long as broad………………..9 9. a. Leaves have an elliptical shape………American Beech (Fagus grandifolia) b. Leaves are toothed and lobed…..………Sugar Maple (Acer Saccharum)