Glencoe BiologyUnit 4:
History of Biological DiversityWebQuestThe Fossils of Antarctica Hominid Fossils
THE FOSSILS OF ANTARCTICA Introduction Two hundred million years ago, all of the continents on Earth were
joined in one large supercontinent scientists call Pangaea. The formation
of Pangaea dried up many shallow seas, which led to the evolution of
new species on land. This is the time during which mammals first began
to appear. During the Mesozoic Era, around 190 million years ago, Pangaea
began to break up. The breakup resulted in two landmasses: Laurasia,
the northern group of continents, and Gondwanaland, the southern group
of continents. Gondwanaland included South America, Antarctica, Australia,
Africa, and India. By the end of the Cretaceous Period 65 million years
ago, Africa and South America had moved apart. By 43 million years
ago, Australia and Antarctica had separated and moved to their present
locations. How do we know that these events actually happened? You have probably
noticed that South America and Africa seem to fit together like puzzle
pieces. Because of this fit, many people wondered if the continents
once were joined. A German scientist named Alfred Wegener proposed
that all of the continents once had been joined in a supercontinent
that he called Pangaea. He suggested that Pangaea began to break apart
millions of years ago, and that the continents continued to move until
they reached their present locations. He called his hypothesis continental
drift. Today, Wegener’s hypothesis is known as the theory of plate
tectonics. Wegener was the first scientist to base his hypothesis on
more than the fit of the continents. He collected data on rock formations,
fossils, and climates to support his hypothesis. Wegener found the
same rock formations and fossils in Africa, South America, and Antarctica.
Some of the fossils were of species that grew in only one type of climate,
yet the fossils were found on continents with differing climates. How
could there be fossils of tropical and temperate climate species in
Antarctica, a continent that is permanently covered with ice and snow?
Have any fossils been found in Antarctica that can support Wegener’s
hypothesis, and thus, the theory of plate tectonics? Top
Task Your job in this WebQuest is to discover what fossils have been found
in Antarctica, and to identify how those fossils either support or
disprove Wegener’s hypothesis and the theory of plate tectonics. You
will have to find out what kinds of fossils have been found in Antarctica.
You will have to discover how to interpret the meaning of these fossils
as indicators of the climate that once prevailed in Antarctica. Finally,
you will answer a set of questions about the fossils of Antarctica
to demonstrate what you have learned. Top
Resources Look at the web sites given here to find the information that will
enable you to answer questions about Antarctica fossils. - Marine
Fossils from Antarctica. Visit this site for an overview of
the fossils found in Antarctica and what they reveal about the past
climate and geographical location of Antarctica. Scroll down to see
photographs of some of the fossils found on Vega Island, an island
just off the coast of Antarctica.
- Antarctic
Dinosaurs. At this site you can learn more about the
first dinosaur fossils found in Antarctica, including a Late Cretaceous
ankylosaur found on James Ross Island in 1986. Scroll down to find
out why so few dinosaur fossils have been found on this continent.
- Fossils
From Mesozoic Era Antarctica. Go to this site for a brief
discussion of continental drift (now called plate tectonics) and how
it affected Antarctica. There is a good map of Antarctica here. Scroll
down to see an interactive graphic of continental drift with a key
to the continents. Continue to scroll down to see a list of fossils
found in Antarctica.
- When
Dinosaurs Roamed Antarctica... Visit this site to read about
dinosaur and reptile fossils found in the Transantarctic Mountains.
These fossils are from the middle Jurassic, about 175 million years
ago.
- The
Lost World Discovered? At this site you can read an
overview of the fossils found in Antarctica from the first expeditions
to the present. This site includes a short history of human presence
on Antarctica as well.
- Secrets
of the Ice: Antarctica in the Past. Visit this site to learn
about the geologic history of Antarctica. Scroll down to see an interactive
graphic of the breakup of Gondwanaland and the subsequent movement
of Antarctica to its present location.
- Antarctic
Summer - Fossils in Antarctica This report by ABC News Online
discusses the issues surrounding fossils that were found in Antarctica
in 1978. Read the report to learn what types of fossils were found
and what is being done to preserve the exposed fossils that still
exist.
Top
Time 1 class period for Internet research and answering the set of questions Top
Process Read through the following set of questions before you begin your
Internet research. As you explore each site, look for answers to the
questions. Questions about the Fossils of Antarctica - What were the first fossils found in Antarctica? Where and when
were they found?
- What was the first dinosaur fossil found in Antarctica? Where and
when was it found?
- What dinosaur fossil was found on Vega Island in 1986?
- What are the two reasons the fossil found on Vega Island is of
particular importance to understanding the climate and location of
Antarctica millions of years ago?
- The first dinosaur fossil and the fossil found on Vega Island in
1986 were representative of what geologic time period?
- What dinosaur fossil was found in the Transantarctic Mountains
in the summer of 1990-1991? During what geologic time period did this
dinosaur live?
- Besides the fossils already discussed, name the other fossil animals
that have been found in Antarctica.
- Why have so few dinosaur fossils been found in Antarctica?
- Early expeditions to Antarctica reported on seeing fossils, but
they did not collect them. Who first reported seeing fossils of leaves
and stems of plants? Who reported finding beds of coal near the South
Pole?
- How do plant fossils and beds of coal support the idea that Antarctica
once was warmer than it is today?
Top
Conclusion In the process of completing this WebQuest, you’ve become informed
about the fossils found in Antarctica, and what those fossils tell
us about the climate and location of Antarctica millions of years ago.
You have learned that some dinosaur fossils found in Antarctica were
previously found only in the Americas. You have discovered that some
Antarctica fossils were of species that could live only in temperate
or tropical climates. You have developed research skills as you explored
the web sites given and identified the relevant information to answer
the set of questions above. Do you agree with Wegener that Antarctica
must have had a warmer climate millions of years ago? Do you think
that the information you have gathered about Antarctic fossils supports
the theory of plate tectonics? Top
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HOMINID FOSSILS Introduction 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
Task 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
Resources 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
Time 2 class periods for research, filling in the table, and answering a few questions Top
Process 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
Conclusion 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
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