| Date | November 2017 | Marks available | 2 | Reference code | 17N.3.HL.TZ0.04 |
| Level | Higher level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | 04 | Adapted from | N/A |
Question
The graph shows the correlation between the cerebral cortex mass and the number of neurons in the cerebral cortex of three groups of mammals (rodents, primates and insectivores). Each point indicates the mean number from different research studies for the species.
[Source: S Herculano-Houzel (2009) Frontiers in Human Neuroscience, 3, p 31, Frontiers Research Foundation
http://journal.frontiersin.org/article/10.3389/neuro.09.031.2009/full]
State which group has the lowest percentage of cerebral cortex mass.
Suggest advantages of the cerebral cortex containing a high percentage of the brain’s neurons.
Suggest a role for the cerebral cortex in rodents such as rats and mice.
Explain how the cerebral cortex in humans differs from other mammals.
Markscheme
rodents
a. more neurons means more synapses/connections
b. higher cognitive ability
c. capacity for information processing increased
OWTTE
[Max 2 Marks]
a. sensory function
b. information processing
c. memory/learning
d. motor function
Do not accept “language”
[Max 1 Mark]
a. parts/lobes/proportions more highly developed in humans «than in other animals»
b. folding/wrinkles/sulci/gyri
c. increases surface area
d. larger mass of cerebral cortex «relative to body mass»
e. enables higher order functions
Do not accept answers that only refer to the “brain” in general instead of the “cortex”
[Max 3 Marks]
