General Biology II (BIOL 1020) Spring 2009
KEY FOR HOMEWORK ASSIGNMENT #1:
Below each question I’ve given the general answer I was looking for. Answers are in blue
Tahoma font, questions in black Times New Roman.
ANSWERS FOR THE GREAT HUMAN MIGRATION
1. (A) According to the article, what two theories have been proposed to explain where
and when humans originated? (B) Which of these theories has the most support, and what
is the evidence that supports it?
(A) The two theories are the Out-of-Africa theory, which suggests that
modern humans originated in Africa and then moved to other parts of
the world. The multi-regional theory suggests that an ancestor of
modern humans migrated out of Africa, and modern humans evolved
separately in several locations.
(B) The Out-of-Africa theory has the most support. Mitochondrial DNA
evidence has traced our ancestry to a common origin, which was in
Africa. More recent use of nuclear DNA has also found a common
origin in Africa. Also, all of the oldest modern human fossils have been
found in Africa.
2. (A) What was found in the caves of Qafzeh and Skhul, and why were they considered
important? (B) Why does it appear that the modern humans who lived in or near these
caves are a “dead end” as far as human migration is concerned?
(A) Remains of 11 modern humans were found (along with more
Neanderthal-looking tools), dated to 90-100,000 years ago. These are
the oldest modern human remains located outside of Africa.
(B) These humans died out rather rapidly, perhaps due to competition
with Neanderthals. There’s no evidence that this group of migrants
expanded beyond this point.
3. (A) What are the two main departure points for ancient humans leaving Africa, and
which pathway seems to currently have the most archeological support? (B) After leaving
Africa, when do modern humans show up in each of the other continents?
(A) The two main routes are across the Sinai peninsula in northern Africa,
and across an ancient land bridge near the Bab el Mandeb strait at the
southern end of the Red Sea. The southern land bridge has more
support, because it kept migrant closer to the sea, with probably a
better climate and more food.
(B) Modern humans arrive in Asia around 70-80,000 years ago, to
Australia around 45,000 years ago, to Europe around 40,000 years
ago, and to North America around 15,000 years ago.
