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.
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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.
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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.
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2 class periods for research, filling in the table, and
answering a few questions
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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?
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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?
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