A bird-watcher sees a small yellow bird in a tree. Explain to the bird-watcher how he can use a dichotomous key to identify the bird. Assume he does not know anything about dichotomous keys. Then, write two steps of a dichotomous key that would be helpful for the bird-watcher.(2 points)

Answer 1

To use a dichotomous key to identify the bird, the bird-watcher needs to follow a series of choices based on observable characteristics of the bird. The key will provide pairs of statements about characteristics, and the bird-watcher will choose which statement best describes the bird he is observing. By following these choices, he will eventually narrow down the possibilities and identify the bird.

Two steps of a dichotomous key that would be helpful for the bird-watcher in identifying the small yellow bird could be:

Step 1: Does the bird have a distinct black stripe running through its eye?
- Yes: Proceed to Step 2.
- No: Go to Step 3.

Step 2: Is the bird's beak long and slender, suited for probing into flowers and extracting nectar?
- Yes: The bird is likely a Goldfinch (family Fringillidae).
- No: Consider other possibilities listed in the key.