Question

Some lizard species show positive allometry in head width, with larger individuals investing disproportionately more in musculature leading to wider heads. To test for positive allometry in a study population, a researcher measures body size and head width for 100 individuals and fits a straight line to a log-log plot of these two traits. Which one of the following estimated values of the slope indicates support for positive allometry?

• A. 0
• B. 0.5
• C. 1
• D. 1.5

Hint:

Positive allometry is indicated by a slope greater than 1 in a log-log plot of body size vs. trait size.

Answer 1

The Correct Option is D

Step 1: Understanding positive allometry.
Positive allometry occurs when larger individuals invest more in a particular trait than smaller individuals. This results in the trait growing faster than body size. In a log-log plot, the slope represents the ratio of growth rates between body size and the trait. 
Step 2: Interpreting the slope. 
- A slope of 0 would indicate no relationship between body size and the trait. 
- A slope of 0.5 would suggest a sublinear relationship, meaning the trait grows slower than body size. - A slope greater than 1 (such as 1.5) indicates positive allometry, where the trait grows faster than body size. 
Step 3: Conclusion. 
The correct answer is (D) 1.5, as it indicates positive allometry, with the trait growing disproportionately faster than body size.