Based on the information given in the passage, the terms ilium and sacrum most likely are classified as
The Lucy Fossil: Female or Male?
Evolutionary biologists have long debated the origin of the human species. They have spent countless hours looking
for human remains, especially of our most primitive ancestors. Many believe the search ended when paleontologist
Donald Johnson found a single arm bone sticking out of the sandy hillside of a slope in Hadu, Africa. That one bone led
to the unearthing of a skeleton nearly 40 % complete. Its official name is “AL-288-1,” but it was nicknamed “Lucy” by
her discoverer. From the beginning, Lucy was considered an adult female. Recently, however, a group of researchers
has questioned Lucy’s gender. These researchers believe that Lucy may actually be a male. Two scientists present
their viewpoints as to the sex of Lucy below:
The small body size of the Lucy fossil led us to originally believe that Lucy was female. We also put together the
shattered remains of her pelvis, including remains of her ilium and sacrum, and found that she had a wider sacrum and
shallower pelvis. This gives her a small, kidney-shaped birth canal. This canal would be wide enough because her
newborn infant’s head would be small, smaller certainly than modern humans and about the size of a chimpanzee.
We did our own reconstruction of the “AL 288-1” (Lucy) fossil. Our reconstruction shows that the shape of Lucy’s
pelvis was just too narrow to accommodate the birth of a human like fetus, even a small one. Our reconstruction also
showed that her pelvic bones were ridgeless and formed a heart shape, which any anatomist will tell you means the
skeleton is that of a male. One more piece of evidence is seen in the ilium, which has markings for the attachment of
the broad muscle fibers we see only in males.