Here is a graph of actual measurements of body length upper

Here is a graph of actual measurements of body length (upper line) and of the diameters of two particular segments (15 and 50, lower lines) from a sample of resting individuals of the earthworm Lumbricus terrestris. What do these data suggest about whether the geometric scaling of growth in earthworms is isometric? Explain your answer.

500 L=102m,934 102m334 100 10 10E 4-5.3m%0.34 d15o53m 0.34 doy4.2mb0.32 ds0\"4.2m3 32 50 0.01 0.1 10 Body mass (g) (uuu) alaw ep01uaw6as 34 32 7 (uuu) 4]6ual Apog

Solution

Isometric growth means all parts of the body are growing at the same rate. The worms are growing isometrically because the mass exponent is about 1/3 which would be accurate for length (1) to mass (3) scaling.