Anthropology 1022
Lab 2 – Brain and Body Size Evolution
Assignment
Combining results for your cranial and postcranial measurements, what can you interpret
about the timing and development of locomotion, brain and body size?
How do your
observations fit into the broader patterns of human evolution? (250 words)
Response:
The cranial measurements show that early humans' brains got larger and more complex as
their bodies grew larger and they met new environmental challenges. They were able to
process and store more information because of this cranial and brain alteration. As a result,
early humans had a substantial advantage in their social interactions and contacts with
unfamiliar ecosystems. The only exception to this rule is the evolution of the Neanderthal
head. They possessed larger skulls and brains than modern humans because they also had
larger bodies, demanding greater mental capacity. Human skulls also have less prognathism
than earlier species, which is most likely due to a decrease in the number of teeth and
chewing muscles. This development could be the result of dietary changes caused by human
evolution, which drove them to consume more prepared meals and meat rather than fibre
plants and fruits with tough skins.
The femur measurements show the species' evolution in their bodies. Although both
Australopithecus and Homo erectus originated in East Africa, the femur length differs
significantly. The fossils of Australopithecus preserved climbing features, which may explain
why their femurs are substantially shorter than those of Homo erectus. The Homo
erectus' long, thin structure helped keep the body cool as it adapted to the hot, dry
conditions. Neanderthals' bodies were wider but not much longer than Homo erectus'.
Neanderthals' short and wide bodies helped them retain heat in their cold-climate
surroundings. Finally, Homo sapiens are not significantly taller than Neanderthals, but are
thinner, as evidenced by femur head measurements.
Grading Rubric
Please do not delete this rubric. The TAs will use this rubric to grade your discussion activity.
The discussion activity will be graded out of 10 marks.
Exceptional Response
Meets Expectations
Needs More Details
Marks
Summary and
discussion of the
major differences in
cranial
measurements
All observed differences
in cranial morphology are
accurately described and
thoughtfully interpreted.
The most significant
differences in cranial
morphology are
described and
interpreted
Differences are
inadequately described
and interpreted
4
4 marks
2-3 marks
0 - 1 mark
Summary and
discussion of the
major differences in
femur
measurements
All observed differences
in femur morphology are
accurately described and
thoughtfully interpreted.
The most significant
differences in femur
morphology are
described and
interpreted
Differences are
inadequately
described and
interpreted
3
3 marks
2 marks
0-1 mark
Integration into
discussion of broader
trends in human
evolution
Thoughtful articulation of
how the observed
patterns in these species
relate to broader trends
in human evolution with
Some relevant discussion
of how the observed
patterns relate to broader
trends in human
evolution
No contextualization
of the observed trends
relative to broader
pattern of human
evolution
2
2
