Some last minute tips and sample questions:

The midterm will be held in the regular lecture room. Remember to bring an HB pencil and a calculator.

I have had some questions regarding interpretation of slope estimates in allometric equations. I hope this summary will be helpful.

If log y is regressed on log x:

1) when b > 1: y increases with x at an increasing

rate

2) when b = 1: y increases with x at a constant rate

(isometric relationship)

3) when 0 < b < 1: y increases with x at a decreasing

rate (e.g. whole-body metabolic rate).

4) when b = 0: no relationship between y and x (no

scaling)

5) when b > 0: y decreases with x at a decreasing

rate (e.g. mass-specific metabolic rate).

See figures below to help visulize this.

Sample questions:

1. Among a group of mammals, organ “y” scales allometrically with body mass. For species weighing 1 kg, organ “y” = 2.3% of body mass. For species weighing 10 kg, organ “y” = 1.8% of body mass. What is the slope of the regression of log”y” on log body mass?

A: b > 0

B: 0 < b < 1

C: b = 1

D: b > 1

Answer : B

2. An organism in an aquatic environment that varies from 5°C to 8°C has a constant body temperature of approximately 9°C. This organism is a:

A: homeothermic ectotherm

B: poikilothermic endotherm

C: poikilothermic ectotherm

D: homeothermic endotherm

Answer : A

3. Which of the following statements is false?

A: Traits may be lost through genetic drift

B: Convergent evolution occurs when closely related organisms exhibit similar traits

C: Only natural selection on genetic variation can give rise to adaptations

D: Mutations appear by chance, but may be maintained by selection

Answer : B

Good luck and contact me if you have questions...