HL 2 Biology

D.3c: Human Evolution & Culture

Cranial Capacity and Diet (p.320)

1 a) As the cranial capacity increases the dietary energy increases as well. The most largest cranial capacity in seen in the Early H. sapiens compared to the other primates, as it has a high dietary energy. Anomalies include the Modern chimpanzee and P.boisei which did not have a increase in dietary energy in relation to its increase in cranial capacity. 

b) As the cranial capacity increased, the hominids may have obtained a greater intelligence, enabling them to   earn a greater diet quality. With a greater intelligence, the hominids can use their tools in a more sophisticated manner. Using the tools, they may be able to hunt and kill animals with more ease and more efficiently than how the early hominids obtained resources.

2 a) The prognathism, the lower part of the face, of the fossil will enable to suggest that there was an increase in meat consumption as the size of the jaw and teeth evolved over time. The jaw has become more flattened and teeth have become smaller in size as the hominids diet has evolved to become more rich in meat consumption, which needs less force to chew down compared to vegetables.

b) This change to a more carnivorous diet might have been important in the evolution of humans as the consumption of this diet may have enabled more nutrients to be consumed. With more nutrients stored in the bodies, it enables humans to live a longer life and provide further brain growth. As the brain developed, greater intelligence was able to be obtained and helped humans to live a more efficiently.

3 a) As the relative diet quality increased, so did the relative brain size.

b) A reason for humans being above the trend line for this relationship includes how humans were able to obtain a larger brain size compared to other primates, enabling them to have greater intelligence and were able to develop more efficient ways of obtaining a better diet quality.


One thought on “D.3c: Human Evolution & Culture

  1. Grade 6 A consistent and thorough understanding of the required knowledge and skills, and the ability to apply them in a wide variety of situations. Consistent evidence of analysis, synthesis and evaluation is shown where appropriate. The student generally demonstrates originality and insight.

    Data-based question: Page 320

    • positive relationship
    • as cranial capacity increases, % of resting energy allocated to the brain increases
    • the primates with the smallest cranial capacity used as little as 9% of resting energy to the brain
    • the primates with the largest cranial capacity used as much as 24% of resting energy to the brain

    • the brain consumes larger amounts of energy than other organs
    • neurons require much ATP for active transport

    • butchery marks found on animal bones associated with hominid fossils
    • stone tools suitable for hunting/scavenging associated with hominid fossils
    • hominid tooth morphology adapted for meat eating
    • large concentrations of large animal bones associated with hominid fossils

    • carnivorous diets have more calories than herbivorous diets
    • carnivorous diets have more protein/amino acids than herbivorous diets
    • carnivorous diets have more fat than herbivorous diets
    • more calories/protein/fat provides more energy for a larger brain

    • positive relationship/ as relative diet quality increases, relative brain size increases

    • human brain might use energy more efficiently
    • other factors than diet/ sexual selection/ social competition for intelligence

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