A Population of Salamanders Live Along the Edge of a North-South

question 68

Multiple Choice

A population of salamanders live along the edge of a north-south mountain range.The populations from the east and west slope eventually join in a low northern pass and interbreed,producing fertile offspring,but they do not circle around the southern edge because of a desert barrier.When glaciers move southward,the populations are pushed south of the northern pass and are isolated.While isolated,the two populations develop enough differences over time that when the glaciers retreat north and the salamanders again share the same pass,they no longer mate at the same time,nor can they produce fertile offspring.These salamanders

• A) began as one species and therefore remain one species.
• B) were originally two species and remain two species.
• C) were originally one species but are now two species.
• D) the number of species cannot be determined from the information given.

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Definitions:

Squared Deviation

The square of the difference between an observed value and the mean, used in statistical analysis to measure variance.

Mean

The arithmetic average of a set of values, calculated by summing all the values and then dividing by the number of values.

Variance

A measure of the dispersion or spread of a set of data points around their mean value.

Variance

A measure of how much the values in a data set differ from the mean of that set.