Have you ever visited the primate house at
a local zoo or watched a television program
about primates? Many people are amused at the
antics of gorillas, chimpanzees, monkeys, and
lemurs as they eat, play, and explore. Did
you know that humans are primates, too? All
primates have opposable thumbs, a relatively
large brain, good binocular vision, and flexible
joints. The earliest primates were prosimians,
a group that includes present-day lemurs. Humanlike
primates were called anthropoids. Present-day
anthropoids include the monkeys and the hominids-apes
and humans. Although humans, gorillas, and
chimpanzees are close cousins genetically,
humans did not evolve from the great apes.
Instead, humans and apes probably evolved from
a common ancestor between 8 and 5 million years
ago. These two different groups formed the
hominids - primates that can walk upright on
two legs. Whereas the apes continued to evolve
into the gorillas, chimpanzees, bonobos, orangutans,
and gibbons of today, humans followed a different
path. What hominids were the ancestors of present-day
humans? How long ago did human ancestors split
off from the rest of the hominids? Where did
humans first evolve? Why is there just one
species of humans alive today? These are some
of the questions you will explore in this WebQuest
on hominid fossils.
Top
Your job in this WebQuest is to learn all
about the evolution of humans. You will learn
about the earliest hominids that may be part
of the evolution of humans, and about the fossils
that have been found which support this idea.
You will look at photographs of these fossils
and read about their similarities and differences.
You will find out how scientists have pieced
together the story of human evolution, and
discover that the story is far from complete.
You will fill in a table that lists which hominids
play a part in human evolution. Finally, you
will answer a few questions about hominid fossils
to demonstrate what you have learned in your
Internet research.
Top
Look at the web sites given here to find the
information that will enable you to complete
your table on hominid fossils and answer a
few questions.
- Prominent
Hominid Fossils. Visit this site
for a comprehensive listing of all hominid
fossils that are important either for
their scientific or historic interest.
Scroll down and click on any photo to
see a larger image and a description
of the fossil.
- The
Evidence: Hominid Fossils. Go
to this University of Texas site to learn
about the more important hominid fossils
and what they can tell us about the evolution
of humans. This is a very interesting
site.
- Human
Evolution. Visit this site to
see a proposed chart of human evolution
from 5 million years ago to the present.
This chart illustrates the best fit for
known fossil specimens to date, but it
is not accepted totally. As new fossils
are found, they tend to impact thoughts
about human evolution.
- Human
Evolution: The fossil evidence in 3D. Go
to this site for an interactive comparison
of the crania of five modern and five
fossil primates. You will need shockwave
plugin (available here) to view the gallery.
Hold down the lefthand button on your
mouse and move the cursor over each photograph
to see the front and side views of each
cranium.
- A
Science Odyssey: You Try It: Human Evolution
Activity. At this site you can
use your mouse to move through a timeline
of human evolution. You can stop at any
time from 5 million years ago to the
present to learn about the hominid species
that may, or may not, be a part of human
ancestry
- Early
Human Evolution. Visit
this site by Palomar College, San Marcos,
California for an online course on human
evolution. Click on early transitional
humans to learn more about the earliest
hominid species. Then scroll down and
click on nest topic to read more about Homo
erectus.
- Human
Ancestry: Species. Go to this
site to see a timeline with the hominid
species from each time period. Click
on any highlighted species name to read
a short article about that species. This
is a very detailed and excellent site.
- Early
Human Phylogeny. At this
Smithsonian Institution site you can
see another timeline showing the evolution
of hominids over the last 5 million years.
Scroll down and click on any species
name to learn more about that species.
Or you can click on catalog to see a
particular specimen in the National Museum
of Natural History's collection.
- New
Hominid Species Complicates Early Hominid
Evolution. Visit this site to
read about a 3.5 million-year-old skull
found in Kenya in 1998-1999. This skull
is a new species called Kenyanthropus
platyops. It is strikingly different
from Australopithecus afarensis fossils
from the same place and time period.
- Guided
Tour - Hominid Evolution. At
this site you can learn about the earliest
hominids and see photographs of the fossils.
You can also learn more about associated
topics, such as bipedalism, at this site.
Top
2 class periods for research, filling in the
table, and answering a few questions
Top
Now that you have completed your research
on hominid fossils, prepare a table like the
one below with the information that you have
gathered on each of the species listed. For
each species, list the location in which the
first fossils of its type were found and the
estimated age of that fossil. You will need
to look at all of the web sites listed in order
to complete the table. Once the table has been
filled in, answer the questions that follow.
Table 1. Hominid Fossils
| Genus
and species |
Location
of Fossil |
Estimated
Age of Fossil |
Ardipithecus
ramidus |
|
|
| Australopithecus
anamensis |
|
|
| Australopithecus
afarensis |
|
|
| Australopithecus
africanus |
|
|
| Australopithecus
aethiopicus |
|
|
| Australopithecus
robustus |
|
|
| Australopithecus
boisei |
|
|
| Homo
habilis |
|
|
| Homo
erectus |
|
|
| Homo
ergaster |
|
|
| Homo
heidelbergensis |
|
|
| Homo
neanderthalensis |
|
|
| Homo
sapiens |
|
|
Questions about Hominid Fossils
- A new species named Kenyanthropus platyops was
found recently in Kenya. Between what two
species would you place this species in the
above table, and why?
- Another new species was discovered in Ethiopia
in 1999. What is the genus and species of
this fossil? Where would you place it in
the above table?
- Name three of the clear trends in the evolution
of hominids from early australopithecines
to recent humans. For example, one clear
trend is increasing brain size.
- Which step in hominid evolution came first - bipedal
locomotion or larger brains? How do scientists
know this?
- What happened about 8 to 5 million years
ago in Africa that may have led to the development
of many different species of hominids?
- Why are Neanderthals sometimes given the
name Homo sapiens neanderthalensis?
- Why is there still so much controversy
over the evolution of humans from hominids?
Top
In the process of completing this WebQuest,
you've become informed about the hominid fossils
that may be part of the story of human evolution.
You have learned about many hominid fossils
and the species they represent. You have developed
critical thinking skills as you explored the
environmental changes that may have led to
the evolution of bipedal hominids. Do you think
scientists have enough information to draw
a clear timeline of the evolution of humans?
Top
