Living Environment Translated English 2014 | Page 40

e. Homo sapiens first appeared about 400,000 years ago.
f. Cro-Magnon humans and Neanderthals coexisted in many
places until Neanderthals disappeared about 30,000 years
ago.
 Neanderthals had short, heavy bodies with thick
bones, small chins, and heavy brow ridges. Family
groups lived in caves and used stone tools to hunt
large animals. They appeared about 125,000 years
ago and disappeared about 30,000 years ago. They
are NOT considered a direct ancestor of modern
humans.
 Cro-Magnons had about the same physical
appearance as modern humans but they were
much shorter. They lived in caves, made store
carvings, and buried their dead. They first painted
bison, horses and people carrying spears. They
seem to have appeared on the earth about 40,000
years ago and disappeared about 10,000 years ago.
g. Homo sapiens looked like modern humans and are
believed to be our direct ancestors.
15.Five factors that can lead to evolution:
a. Genetic drift- gene pool can change due to chance alone.
b. Gene Flow- (migration)- organisms move into and out of
an area. This changes the alleles that are in the
populations.
c. Mutation- new alleles form through mutation. Mutations
create the genetic variation necessary for evolution.
d. Sexual selection- certain traits improve mating success.
Alleles for these traits increase in frequency.
e. Natural Selection- certain traits may be an advantage for
survival. Alleles for these traits increase in frequency.
16.Evolution is a continuous process. Environments are constantly
changing and evolution is a response to these changes.