Track Trait Frequency
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Middle School Life Science › Track Trait Frequency
A class studies a constant population of 30 guppies over 5 generations. The trait is tail color: bright or dull. Trait frequency can be tracked by comparing the proportion of bright-tailed guppies across generations.
Which statement about trait frequency is supported by the table?
Bright tails become more common from Generation 1 to Generation 5, even though they do not increase every generation.
Bright tails are the most common in Generation 2, so the frequency must keep increasing after Generation 2.
Because bright tails decrease after Generation 2, the trait is gone forever and cannot return.
The frequency of bright tails cannot change because the population size stays 30 each generation.
Explanation
The core skill is tracking how the frequency of a trait, such as tail color in guppies, changes over generations in a population. Frequency tracks the proportion of the population that has a particular trait, like bright tails versus dull tails, to observe long-term patterns. Data in a table can show these changes by comparing proportions across generations, showing an overall increase in bright tails despite not rising every time. To check the frequency change, calculate percentages for each generation and assess the net trend from beginning to end. A common misconception is that a decrease in one generation means the trait is gone forever, but frequencies can rebound and change direction over time. Tracking trait frequency helps explain population changes over time through evolutionary mechanisms. This understanding reveals how traits adapt and persist in dynamic ecosystems.