answer

Alewives ar small fish found in oceans and lakes, Alewives eat prey such as zooplankton, which come in different sizes, Alewives with a bigger gape width, which is the distance between the comers of the fish's mouth, are better at catching bigger zooplankton. Alewives with a smaller gape width are better at catching smaller zooplankton. an alewife with its gape width shown The graphs below describe an isolated population of alewives over a time period long enough for natural selection to occur. The graphs show gape width measurements for a representative sample of the population at the start of this period and for another representative sample at the end. At the start of this time period, the alewives' environment changed. Sample at start Sample at end S e S & eS ars ee 6 > * a_____+_+ + +> 3 4 #5 6 3 4 #5 6 Gape width fmm) Gape width (mm) Describe how the alewife population changed over this time period. Use the theory of natural selection to construct a possible explanation for this change. The average gape width * in the population. This suggests that alewives with larger gape widths were * likely to survive and reproduce than alewives with smaller gape widths. This may have occurred because the average size of zooplankton in the alewives' environment * . After the environment changed, alewives with larger gape widths were likely to be * at catching food