Question 21N.2.SL.TZ0.1b
| Date | November 2021 | Marks available | [Maximum mark: 2] | Reference code | 21N.2.SL.TZ0.1b |
| Level | SL | Paper | 2 | Time zone | TZ0 |
| Command term | Compare and contrast | Question number | b | Adapted from | N/A |
Compare and contrast the effects of temperature on the biomass of autotrophs and heterotrophs with added nutrients.
[2]
a. autotroph biomass decreases and heterotroph biomass increases with higher temperatures;
b. decrease in autotrophs is greater/larger/more than increase in heterotrophs
OR
little difference in biomass (between auto and heterotrophs) at highest temperature/27 °C;
c. autotrophs show smaller and smaller gains in biomass from initial as temperature rises/WTTE;
d. heterotrophs no gain in biomass at 21 °C then larger and larger gains as temperature rises;
Most candidates stated that autotroph biomass decreased and heterotroph biomass increased as temperature increased, but this contrast was only given one mark. Far fewer candidates gave a second worthwhile comparison or contrast. Very few candidates realised that at all temperatures the autotrophs had gained biomass from the initial level, but the gains were less as temperature rose. Similarly, few candidates stated that the heterotrophs had not gained mass at 21°C but gained increasing amounts of biomass as the temperature rose.
