Real-Life Math -- Solution
Solve the question by determining the ratio of each insect's measurements.
Insect 1
With a 2-inch wide head and a 2.5-inch long abdomen, the ratio of this insect's head to its abdomen is 2:2.5.
2 inches / 2.5 inches = 0.8 inches
Its eye width measures 0.2 inches and the space between its eyes is 0.3 inches. Therefore the ratio is 0.2:0.3.
0.2 inches / 0.3 inches = 0.66 inches
Compare these ratios to those ratios in species A and species B. The ratios for Insect 1 show it should be categorized as species B.
Insect 2
This insect's head is 4 inches wide and it has a 10-inch long abdomen. The ratio of head width to abdomen length is therefore 4:10.
4 inches / 10 inches = 0.4 inches
Its eye width is 0.3 inches and the space between its eyes is 1.2 inches. Therefore the eye width/eye space ratio is 0.3:1.2
0.3 inches / 1.2 inches = 0.25 inches
These ratios show that Insect 2 should be categorized as species A.
Insect 3
You're down to measuring the last insect. Its head width is 1.5 inches and it has an abdomen length of 2.5 inches. Therefore, the ratio is 1.5:2.5
1.5 inches / 2.5 inches = 0.6 inches
Its eye width measures 0.6 inches and the space between its eyes measures 0.9 inches. Therefore the eye width/eye space ratio is 0.6:0.9.
0.6 / 0.9 = 0.66
According to your previous calculations, this insect's eye width and eye space ratio would classify it as species B but the head width and abdomen length ratio doesn't fall under either group.
So what species do you categorize Insect 3 as?
"There isn't a correct answer," says entomologist Karen Needham. She explains that this is often the case when it comes to biology. "You can either throw the ratio out and find a different set of measurements or you can include a caveat explaining that this particular ratio only works part of the time."
Needham says she spends a lot of time teaching her first-year university students that there is rarely one correct answer when doing biology calculations. "If you're always looking for a perfect answer, then biology isn't for you," adds Needham. "If you look for absolutes, you'll never find them."