A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.
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Transcript of A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.
![Page 1: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/1.jpg)
Dichotomous
Keys
![Page 2: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/2.jpg)
Dichotomous
Keys
A dichotomous key is a tool
that scientists can use to identify an unknown
organism or specimen.
![Page 3: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/3.jpg)
Dichotomous
Keys
Examples include…
insects
![Page 4: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/4.jpg)
Dichotomous
Keys
trees
![Page 5: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/5.jpg)
Dichotomous
Keys
rocks
![Page 6: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/6.jpg)
Dichotomous
Keys
and shells.
![Page 7: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/7.jpg)
Dichotomous
Keys
The word dichotomo
us means
“divided in two parts.”
![Page 8: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/8.jpg)
Dichotomous
Keys
Characteristics of a
Dichotomous Key
![Page 9: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/9.jpg)
Dichotomous
Keys
• Consists of a series of two
part statements
that describe the
characteristics of a specimen.
![Page 10: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/10.jpg)
Dichotomous
Keys
![Page 11: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/11.jpg)
Dichotomous
Keys
• The user is
presentedwith two choices.
![Page 12: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/12.jpg)
Dichotomous
Keys
![Page 13: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/13.jpg)
Dichotomous
Keys
As the user
makes a choice,
they are led to a
new branch of the key.
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Dichotomous
Keys
![Page 15: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/15.jpg)
Dichotomous
Keys
• In the end, the
user is led to the
name of the
specimen.
![Page 16: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/16.jpg)
Dichotomous
Keys
![Page 17: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/17.jpg)
Dichotomous
Keys
Constructing a
Dichotomous Key
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Dichotomous
Keys
• Separate the
specimens into two groups
based on one
characteristic.
![Page 19: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/19.jpg)
Dichotomous
Keys
Example:A deck of
playing cards could be
separated into black cards and red cards.
![Page 20: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/20.jpg)
Dichotomous
Keys
• Continue to separate the groups until
each specimen has its own set of characteristic
s.
![Page 21: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/21.jpg)
Dichotomous
Keys
Example:Red cards can be
separatedinto hearts /
diamonds, thenpicture / number
cards thenmale / female
cards, etc.
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Dichotomous
Keys
Make the choice a
positive one –
for example, something
“is” instead of “is
not.”
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Dichotomous
Keys
Example:2a.Black card is a spade…….42b.Black card is a club……….5
4a.Spade is a picture card…64b.Spade is a number card…7
6a.Picture card is male……….86b.Picture card is female…..9
![Page 24: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/24.jpg)
Dichotomous
Keys
•Start both
choices in a pair
with the same word.
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Dichotomous
Keys
Example:2a.Red card is a
heart……….42b.Red card is a diamond……5
![Page 26: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/26.jpg)
Dichotomous
Keys
•Start the next pair
with different words.
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Dichotomous
Keys
Example:2a.Red card is a heart……….42b.Red card is a diamond……5
4a.Heart is picture card…….64b.Heart is number card…….7
6a.Picture card is male……….86b.Picture card is female……9
![Page 28: A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.](https://reader037.fdocuments.in/reader037/viewer/2022103111/55175811550346176e8b46ac/html5/thumbnails/28.jpg)
Dichotomous
Keys
There should be one less
step than the total number
of specimens to
be identified.