Question 19M.3.SL.TZ2.5b
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.SL.TZ2.5b |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Suggest | Question number | b | Adapted from | N/A |
Scientists investigated how relative brain mass varied in primate evolution. The graph shows the relative brain mass for species belonging to different primate groups against time of divergence from the common ancestor of modern humans in million years ago (Mya), 0 being the present era.
[Source: S Herculano-Houzel and J H Kaas, (2011), Brain, Behavior and Evolution, 77, pages 33–44.
© 2011 Karger Publishers, Basel, Switzerland]
Suggest one reason that the relative brain mass of Homo is different from Parapithecus and Australopithecus.
[1]
a. human cerebral cortex has extensive folding producing a greater mass ✔
b. better diet/more protein allowed increase in «relative» brain mass in humans ✔
c. others had larger body to protect them from predators «without increase in brain mass» ✔
In parts (b) and (c) few candidates referred to ‘relative’ brain mass thereby providing incorrect responses.
