#12: Using simple keys

The identification of biological organisms can be greatly simplified using tools such as dichotomous keys. It is a written set of choices, each involving two statements, that leads to the name of an organism. Scientists use these to identify unknown organisms.



Consider the following animals. They are all related, but each is a separate species. Use the dichotomous key below to determine the species of each.

Answers:

A: Deerus magnus     B: Deerus pestis     C: Deerus octagis

D: Deerus purplinis    E: Deerus deafus    F: Deerus humpis 

As seen above:

• the keys are mutually exclusive characteristics of biological organisms. 
• they often begin with general characteristics and lead to more specific characteristics.
• you simply compare the characteristics of an unknown organism against an appropriate dichotomous key.
• if the organism falls into one category, you go to the next indicated couplet. 

By following the key and making the correct choices, you should be able to identify your specimen to the indicated taxonomic level.

Try this

Figure above shows single leaves from six different trees. Use the key below to identify which tree each leaf comes from. 

Make a table similar to the one below and put a tick in the correct box to show how you identify each leaf. Give the name of the tree. Leaf A has been identified for you as an example.

Additional sources:

http://www.biologycorner.com/bio1/notes_taxonomy.html

http://biology.clemson.edu/bpc/bp/Lab/104/Labmanual/LabEx/09Keys.pdf

http://www.biologyjunction.com/dichotomous_keying.htm