Spotted or Not

The phenotypic pattern of spots on the dorsal side of the spotted salamander are an excellent way to introduce inquiry and observation into a discussion about basic genetics and patterns in nature. There are some suggested varieties of patterns (below) that will be used in the Spotted or Not activity. The patterns identified are not always perfectly displayed in nature and are meant to be a guide. Students may come up with other patterns in their investigation and should be encouraged to discuss these during the activity.

 

Spot Patterns

Alternate: Alternating spots in a zig-zag pattern (7 spots)

Alternate

A pattern where spots alternate, or are diagonal, from each other on the dorsal side of the salamander from the base of the neck to the start of the tail.

 
Opposite: 2 rows of closely-formed spots (14, in all)

Opposite

A pattern where spots are opposite, or straight across, from each other on the dorsal side of the salamander from the base of the neck to the start of the tail.

 
Random/Absent: 3 smaller spots randomly placed, with some trace amorphous smudges

Random / Absent

Sometimes there is a lack of pattern as described above and there may only be faint traces of spots or random arrangements along the dorsal from the base of the neck to the start of the tail.

 

 

Videos

In these videos, there is a single population of spotted salamanders but they congregate randomly into several groups during the brief window of reproductive activity. Take some time to observe the videos and the salamander activity and think about how the patterns are different. After watching each video take time to collect data on spot patterns that are displayed by watching each video again,  Pause videos along the way to make observations easier since the salamanders are very active and tend to move from placer to place in the vernal pool.

 

Video 1


 

Video 2


 

Video 3