Human Evolution Mini-unit Outline/Study Sheet
Test Date: ________
Know this information.
Part 1. Primates
 Primates are members of a group of mammals that includes humans, apes, monkeys,
and about 200 other species of living things.
 Primates share several important characteristics.
1. They have flexible hands with opposable thumbs.
2. Primates tend to have flat faces and very reduced snouts.
3. Their eyes are on the front – not the sides – of their faces. They see in three
dimensions (3-D). This means that primates receive a separate image coming into
each eye, which is translated by the brain as one three-dimensional image.
4. They have different bones in their forelimbs and hindlimbs. (They have arms
and legs.)
5. They have large, complex brains for their body size.
6. Primates care for their young much longer than most other mammals do.
7. They have complicated social behaviors including friendships and fighting
among competing groups.

The earliest known primate was an insect-eating mammal that resembles today’s
tree shrew. These animals are known only from the fossil record.

About 50 million years ago, early primates split into two main groups: prosimians
and anthropoids.

Prosimians are mostly nocturnal animals with large eyes for seeing in the dark.
Examples of prosimians are lemurs, lorises, and aye-ayes.

Anthropoids are humanlike primates that include monkeys, apes, and humans.

The anthropoids split into two groups. One branch evolved into New World monkeys.
The other branch evolved into the Old World monkeys and hominoids.

Hominoids include gibbons, gorillas, orangutans, chimpanzees, and humans.

The relationships among members of the primate is established by studying fossils
and the nitrogen base sequence of proteins.
Part 2. Modern Humans and Early Ancestors

In Africa about 6 million years ago, hominoids gave rise to a small group of
species called hominids, which include modern humans and our early ancestors.

Early hominids experienced changes in their spinal column and their hip and leg
bones. The spinal column began to curve. Hips became smaller. The femur angled in
from the body. These changes enabled them to walk upright.

Walking upright is called bipedalism. An advantage to being bipedal is freedom to
carry things and use tools.

The first recognized hominids were the Australopithecines. They were short – not
much larger than a modern day chimpanzee. The bones of their fingers were curved.
Their brains were about the same size as a chimp’s, but they were bipedal. Lucy, an
Australopithecus afarensis, is the most complete early fossil of a hominid ever
found. Lucy lived between 2 and 3 million years ago.

The first species to be placed in the genus Homo was Homo habilis. Habilis means
skillful. Homo habilis is the first hominid to be associated with making tools.
H.habilis could use fire but probably could not make fire. Homo habilis had a
larger brain than any of the Australopithecines. Homo habilis lived about 2 to 1.8
million years ago.

Homo habilis was followed by Homo erectus. Erectus means upright. H. erectus is
associated with making fire. H. erectus is also the first of the hominids to leave
Africa. Homo erectus lived about 1.5 million years ago.

The first species of hominid to resemble modern humans is Homo sapiens
neanderthalensis. Neanderthals lived during an ice age. They were short, robust
hominids. They made complex stone tools and had large brains. They were very
muscular. Many of their skeletal remains show evidence of a hard life. They buried
their dead and added flowers and artifacts to the grave. They took care of their
old and wounded family members. Neanderthals lived about 150,000 years ago.

The first fossils of modern humans date to about 40,000 years ago. These humans,
called Cro-Magnons, are designated as Homo sapiens sapiens. Modern Homo sapiens
are associated with developing language, culture, art, and music. Their tools were
much more complex and varied than those of the Neanderthals.
In addition to the information above, be able to recognize artifacts associated with some
of the hominid species. Be able to identify some major characteristics of their skulls.