Download Science of Evolution Jigsaw

Lines of Evidence: The Science of Evolution
Jigsaw Teacher Guide
Directions: The following activity is intended to review or teach the concepts of evolution
through the Jigsaw strategy. Read the steps below for detailed directions.
ƒ Make a transparency, copies, or just read the Introduction to students
ƒ Divide the classroom into 7 groups. For this part of the task, teachers need to divide
students into groups based on different skills if possible because each group
member will be responsible for specific tasks (such as reading out loud, writing
answers, summarizing group thoughts, timing the group, etc.)
ƒ Each group must divide up tasks and identify a reader, a recorder, a timer, and a
presenter. Give each group their designated group sheet which includes directions,
a place to identify each participant’s role, and questions that pertain to their reading.
ƒ The teacher should walk around and facilitate the activity. Additionally, the teacher
should help monitor whether group “timers” are doing their job.
ƒ When groups are finished reading and answering reading questions, the groups
should complete a 2-3 sentence summary. The teacher has to approve each
summary before the group can move to the last step. It is important that the teacher
make sure group summaries give a brief overview of the information without getting
too specific. Students do not need to know specific evidence to support evolution,
but they do need to understand the general evidence (fossils, characteristics of
once-living organisms, geology, natural selection, ecology, etc.) that supports life is
old and has changed over time. The fossil record, although not always clear and has
missing pieces, as well as other evidence is used to show this change over time.
ƒ When all groups are finished, the teacher will re-organize the classroom into 4
groups of 7. One person from each of the original 7 groups should be in each group.
The teacher may want to consider putting all “Readers”, “Timers”, “Recorders”, and
“Presenters” in one group to make things easier. In group order (1, 2, 3, etc.), each
group member should share his/her group’s summary. The other new group
members should record the summary on their Science of Evolution Student Notes
sheet. (You may want to consider providing each person a sheet of plain copy paper
or construction paper to write their summary on in larger print to make it easier for
other group members to copy down instead of just going by the reading)
ƒ When students are finished in groups, have them return to their correct seats, but
keep their notes out. Students then use their notes to complete a graphic organizer.
There are three versions of the graphic organizer to allow for differentiation. One
graphic organizer for low level students provides a word bank that is split into two
sections so the information does not seem too overwhelming. Another graphic
organizer contains boxes and a word bank. Another graphic organizer for higher
level students contains only title boxes and students must come up with the rest.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
The Science of Evolution: Student Notes
Name_______________________ Blk____
At the heart of evolutionary theory is the basic idea that life has existed for billions of years
and has changed over time. Overwhelming evidence supports this fact. Scientists continue to
argue about details of evolution, but the question of whether life has a long history or not was
answered in the affirmative at least two centuries ago.
The history of living things is documented through multiple lines of evidence that converge to
tell the story of life through time. These multiple lines of evidence are described below.
Group 1: Fossil Evidence ____________________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Group 2: Transitional Forms _________________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Group 3: Homologies: Anatomy ______________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Group 4: Homologies: Development Biology ____________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
The Science of Evolution: Student Notes
Name_______________________ Blk____
Group 5: Chronology and Geology ____________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Group 6: Present-day Examples: Artificial Selection and Ecology
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Group 7: Present-day Examples: Experiments and Nested Hierarchies
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution
Introduction
At the heart of evolutionary theory is the
basic idea that life has existed for
billions of years and has changed over
time. Overwhelming evidence supports
this fact. Scientists continue to argue
about details of evolution, but the
question of whether life has a long
history or not was answered in the
affirmative at least two centuries ago.
The history of living things is
documented through multiple lines of
evidence that converge to tell the story
of life through time. We will explore the
lines of evidence that are used to
reconstruct this story.
These lines of evidence include:
ƒ Fossil evidence
ƒ Homologies
ƒ Distribution in time and space (Chronology & Geology)
ƒ Evidence by present-day examples
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 1
Fossil Evidence
The fossil record provides snapshots of the past that, when assembled, illustrate a panorama
of evolutionary change over the past four billion years. The picture may be smudged in
places and may have bits missing, but fossil evidence clearly shows that life is old and has
changed over time.
In the 17th century, Nicholas Steno shook the
world of science, noting the similarity
between shark teeth and the rocks commonly
known as "tongue stones." This was our first
understanding that fossils were a record of
past life.
Two centuries later, Mary Ann Mantell picked
up a tooth, which her husband Gideon
thought to be of a large iguana, but it turned
out to be the tooth of a dinosaur, Iguanodon.
This discovery sent the powerful message
that many fossils represented forms of life
that are no longer with us today.
Today we may take fossils for granted, but we continue to learn from them. Each new fossil
contains additional clues that increase our understanding of life's history and help us to
answer questions about their evolutionary story. Examples include:
Indication of Interaction
This ammonite fossil shows punctures that some scientists have
interpreted as the bite mark of a mosasaur, a type of predatory
marine reptile that lived at the same time as the ammonite.
Damage to the ammonite has been correlated to the shapes and
capabilities of mosasaur teeth and jaws. Others have argued that
the holes were created by limpets that attached to the ammonite.
Researchers examine ammonite fossils, as well as mosasaur
fossils and the behaviors of limpets, in order to explore these
hypotheses.
Clues at the cellular level
Fossils can tell us about growth patterns in ancient animals. The
picture at right is a cross-section through a sub-adult thigh bone
of the duckbill dinosaur Maiasaura. The white spaces show that
there were lots of blood vessels running through the bone, which
indicates that it was a fast-growing bone. The black wavy
horizontal line in mid-picture is a growth line, reflecting a
seasonal pause in the animal's growth.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 1
Fossil Evidence
Group Members: ____________________________________________________________
Directions: Each group member will have a specific role in this task. Identify below which
group member will be responsible for each role. Then, follow the steps:
Reader ____________________________
Recorder ___________________________
Timer _______________________________
Presenter ___________________________
1. Each group member will first read the information and the reading questions silently. The
Timer will make sure that no more than 5 minutes is spent reading silently. However, if
everyone is finished reading, the group can move to the next step.
2. The Reader of the group will read the information out loud to the group. During this time,
group members should be following along as well as looking for answers to the
designated questions.
3. After reading, the group should discuss and identify answers to the reading questions.
When the group is in agreement on correct answers, the Recorder will write the answers
to the questions on the group sheet. The Timer will make sure that no more than 10
minutes is spent answering questions. However, if the group finishes before 10 minutes,
the group can move to the next step.
4. The group will write 2-3 sentences summarizing their information. Use the answers to the
reading questions for the basis of your summary. However, the summary sentences
should NOT include specific fossil names or specific fossil information. Ex. Explain fossil
evidence without using Mosasaur or the Maiasaura.
5. The Reader will read the summary sentences out loud to the group for approval.
6. The Recorder will write the summary sentences on the group sheet.
7. The Presenter will “present” the summary to the teacher for approval. If the summary
needs revisions, the teacher will provide explanations to the presenter. The presenter will
“present” the information to the group for revisions. The Presenter must get approval by
the teacher before the group can move to the next step.
8. Each group member will write the summary sentences of their section on the Science of
Evolution Student Notes sheet.
Reading Questions
1. What does fossil evidence show? _____________________________________________
__________________________________________________________________________
2. What is a problem with fossil evidence? ________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 1
3. What did the early fossil discoveries described demonstrate? _______________________
__________________________________________________________________________
4. What example was used from the fossil record to indicate interaction between once living
organisms?
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
5. What evidence from the fossil record was used to provide clues at the cellular level of
once-living organisms?
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 2
Transitional Forms
Fossils or organisms that show the intermediate states between an ancestral form and that of
its descendants are referred to as transitional forms. There are numerous examples of
transitional forms in the fossil record, providing an abundance of evidence for change over
time.
Pakicetus (below left), is described as an early ancestor to modern whales. Although
pakicetids were land mammals, it is clear that they are related to whales and dolphins based
on a number of specializations of the ear, relating to hearing.
The skull shown here displays nostrils at the front of the skull. A skull of the gray whale that
roams the seas today (below right) has its nostrils placed at the top of its skull. It would
appear from these two specimens that the position of the nostril has changed over time and
thus we would expect to see intermediate forms.
Note that the nostril placement in Aetiocetus is intermediate between the ancestral form
Pakicetus and the modern gray whale — an excellent example of a transitional form in the
fossil record!
Our understanding of the evolution of horse feet, so often
depicted in textbooks, is derived from a scattered sampling
of horse fossils within the multi-branched horse evolutionary
tree. These fossil organisms represent branches on the tree
and not a direct line of descent leading to modern horses.
But, the standard diagram does clearly show transitional
stages whereby the four-toed foot of Hyracotherium,
otherwise known as Eohippus, became the single-toed foot
of Equus. Fossils show that the transitional forms predicted
by evolution did indeed exist.
As you can see to the left, each branch tip on the tree of
horse evolution indicates a different genus, though the feet
of only a few genera are illustrated to show the reduction of
toes through time.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 2
Transitional Forms
Group Members: ____________________________________________________________
Directions: Each group member will have a specific role in this task. Identify below which
group member will be responsible for each role. Then, follow the steps:
Reader ____________________________
Recorder ___________________________
Timer _______________________________
Presenter ___________________________
1. Each group member will first read the information and the reading questions silently. The
Timer will make sure that no more than 5 minutes is spent reading silently. However, if
everyone is finished reading, the group can move to the next step.
2. The Reader of the group will read the information out loud to the group. During this time,
group members should be following along as well as looking for answers to the
designated questions.
3. After reading, the group should discuss and identify answers to the reading questions.
When the group is in agreement on correct answers, the Recorder will write the answers
to the questions on the group sheet. The Timer will make sure that no more than 10
minutes is spent answering questions. However, if the group finishes before 10 minutes,
the group can move to the next step.
4. The group will write 2-3 sentences summarizing their information. Use the answers to the
reading questions for the basis of your summary. However, the summary sentences
should NOT include specific fossil names or specific fossil information. Ex. Explain fossil
evidence without using Pakicetids or horse toes.
5. The Reader will read the summary sentences out loud to the group for approval.
6. The Recorder will write the summary sentences on the group sheet.
7. The Presenter will “present” the summary to the teacher for approval. If the summary
needs revisions, the teacher will provide explanations to the presenter. The presenter will
“present” the information to the group for revisions. The Presenter must get approval by
the teacher before the group can move to the next step.
8. Each group member will write the summary sentences of their section on the Science of
Evolution Student Notes sheet.
Reading Questions
1. What are transitional forms? ________________________________________________
__________________________________________________________________________
__________________________________________________________________________
2. Transitional forms are evidence of ___________________________________________.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 2
3. Although Pakicetids were land mammals, how is it clear they are related to whales and
dolphins?
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
4. What demonstrated that an intermediate form existed between the Pakicetus and today’s
Gray whale?
__________________________________________________________________________
__________________________________________________________________________
5. What do the transitional forms of horse fossils demonstrate about horse evolution over
time?
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 3
Evolutionary theory predicts that related organisms will share similarities that are derived
from common ancestors. Similar characteristics due to relatedness are known as
homologies. Homologies can be revealed by comparing the anatomies of different living
things, looking at cellular similarities and differences, studying embryological development,
and studying vestigial structures within individual organisms.
Homologies: Anatomy
An example of homology is the forelimb
of tetrapods (vertebrates with legs).
Frogs, birds, rabbits and lizards all
have different forelimbs, reflecting their
different lifestyles. But those different
forelimbs all share the same set of
bones - the humerus, the radius, and
the ulna. These are the same bones
seen in fossils of the extinct transitional
animal, Eusthenopteron, which
demonstrates their common ancestry.
Individual organisms contain, within their bodies, abundant evidence of their histories. The
existence of these features is best explained by evolution.
Several animals, including pigs, cattle, deer,
and dogs have reduced, nonfunctional digits,
referred to as dewclaws. The foot of the pig has
lost digit 1 completely, digits 2 and 5 have been
greatly reduced, and only digits 3 and 4 support
the body.
Evolution best explains such vestigial features
(feature that an organism inherited from its
ancestor but that is now less functional than in
the ancestor).
People (and apes) have chests that are broader
than they are deep, with the shoulder blades flat
in back. This is because we, like apes, are
descended from an ancestor who was able to
suspend itself using the upper limbs. On the
other hand, monkeys and other quadrupeds
have a different form of locomotion.
Quadrupeds have narrow, deep chests with
shoulder blades on the sides.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 3
Hoatzin chicks have claws on their wings, as do some chickens and ostriches. This reflects
the fact that bird ancestors had clawed hands.
Organisms that are closely related to one another share many anatomical similarities.
Sometimes the similarities are conspicuous, as between crocodiles and alligators, but in
other cases considerable study is needed for a full appreciation of relationships.
Whales and hummingbirds have tetrapod skeletons inherited from a common ancestor. Their
bodies have been modified and parts have been lost through natural selection, resulting in
adaptation to their respective lifestyles over millions of years. On the surface, these animals
look very different, but the relationship between them is easy to demonstrate. Except for
those bones that have been lost over time, nearly every bone in each corresponds to an
equivalent bone in the other.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 3
Homologies: Anatomy
Group Members: ____________________________________________________________
Directions: Each group member will have a specific role in this task. Identify below which
group member will be responsible for each role. Then, follow the steps:
Reader ____________________________
Recorder ___________________________
Timer _______________________________
Presenter ___________________________
1. Each group member will first read the information and the reading questions silently. The
Timer will make sure that no more than 5 minutes is spent reading silently. However, if
everyone is finished reading, the group can move to the next step.
2. The Reader of the group will read the information out loud to the group. During this time,
group members should be following along as well as looking for answers to the
designated questions.
3. After reading, the group should discuss and identify answers to the reading questions.
When the group is in agreement on correct answers, the Recorder will write the answers
to the questions on the group sheet. The Timer will make sure that no more than 10
minutes is spent answering questions. However, if the group finishes before 10 minutes,
the group can move to the next step.
4. The group will write 2-3 sentences summarizing their information. Use the answers to the
reading questions for the basis of your summary. However, the summary sentences
should NOT include specific fossil names or specific fossil information. Ex. Explain fossil
evidence without using Tetrapods or other organisms.
5. The Reader will read the summary sentences out loud to the group for approval.
6. The Recorder will write the summary sentences on the group sheet.
7. The Presenter will “present” the summary to the teacher for approval. If the summary
needs revisions, the teacher will provide explanations to the presenter. The presenter will
“present” the information to the group for revisions. The Presenter must get approval by
the teacher before the group can move to the next step.
8. Each group member will write the summary sentences of their section on the Science of
Evolution Student Notes sheet.
Reading Questions
1. What are homologies? _____________________________________________________
2. How does homology demonstrate that frogs, birds, rabbits, lizards, and the transitional
form Eusthenopteron share a common ancestor?
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 3
3. How are vestigial features a homology? ________________________________________
__________________________________________________________________________
__________________________________________________________________________
4. What evidence suggests that bird ancestors had clawed hands? _____________________
__________________________________________________________________________
5. How does homology demonstrate that whales and hummingbirds come from a common
ancestor?
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 4
Evolutionary theory predicts that related organisms will share similarities that are derived
from common ancestors. Similar characteristics due to relatedness are known as
homologies. Homologies can be revealed by comparing the anatomies of different living
things, looking at cellular similarities and differences, studying embryological development,
and studying vestigial structures within individual organisms.
Homologies: Developmental Biology
Studying the embryological development of living things provides clues to the evolution of
present-day organisms. During some stages of development, organisms exhibit ancestral
features in whole or incomplete form.
Some species of living snakes have
hind limb-buds as early embryos
but rapidly lose the buds and
develop into legless adults.
The study of developmental stages
of snakes, combined with fossil
evidence of snakes with hind limbs,
supports the hypothesis that snakes
evolved from a limbed ancestor.
Toothed whales have full sets of teeth throughout
their lives. Baleen whales, however, only possess
teeth in the early fetal stage and lose them before
birth.
The possession of teeth in fetal baleen whales
provides evidence of common ancestry with
toothed whales and other mammals. In addition,
fossil evidence indicates that the late Oligocene
whale Aetiocetus (to the right), from Oregon, which
is considered to be the earliest example of baleen
whales, also bore a full set of teeth.
Again, these observations make most sense in an evolutionary framework where snakes
have legged ancestors and whales have toothed ancestors.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 4
Evolutionary theory predicts that related organisms will share similarities that are derived
from common ancestors. Similar characteristics due to relatedness are known as
homologies. Homologies can be revealed by comparing the anatomies of different living
things, looking at cellular similarities and differences, studying embryological development,
and studying vestigial structures within individual organisms.
Homologies: Cellular/Molecular Evidence
All living things are fundamentally alike. At the cellular and molecular level living things are
remarkably similar to each other. These fundamental similarities are most easily explained by
evolutionary theory: life shares a common ancestor.
All organisms are made of cells, which consist of membranes filled with water containing
genetic material, proteins, lipids, carbohydrates, salts and other substances. The cells of
most living things use sugar for fuel while producing proteins as building blocks and
messengers. Notice the similarity between the typical animal and plant cells pictured below
— only three structures are unique to one or the other.
Different species share genetic homologies as well as anatomical ones. Roundworms, for
example, share 25% of their genes with humans. These genes are slightly different in each
species, but their striking similarities nevertheless reveal their common ancestry. In fact, the
DNA code itself is a homology that links all life on Earth to a common ancestor. DNA and
RNA possess a simple four-base code that provides the recipe for all living things.
In some cases, if we were to transfer genetic material from the cell of one living thing to the
cell of another, the recipient would follow the new instructions as if they were its own. These
characteristics of life demonstrate the fundamental sameness of all living things on Earth and
serve as the basis of today's efforts at genetic engineering.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 4
Homologies: Developmental Biology
Group Members: ____________________________________________________________
Directions: Each group member will have a specific role in this task. Identify below which
group member will be responsible for each role. Then, follow the steps:
Reader ____________________________
Recorder ___________________________
Timer _______________________________
Presenter ___________________________
1. Each group member will first read the information and the reading questions silently. The
Timer will make sure that no more than 5 minutes is spent reading silently. However, if
everyone is finished reading, the group can move to the next step.
2. The Reader of the group will read the information out loud to the group. During this time,
group members should be following along as well as looking for answers to the
designated questions.
3. After reading, the group should discuss and identify answers to the reading questions.
When the group is in agreement on correct answers, the Recorder will write the answers
to the questions on the group sheet. The Timer will make sure that no more than 10
minutes is spent answering questions. However, if the group finishes before 10 minutes,
the group can move to the next step.
4. The group will write 2-3 sentences summarizing their information. Use the answers to the
reading questions for the basis of your summary. However, the summary sentences
should NOT include specific fossil names or specific fossil information. Ex. Explain fossil
evidence without using Baleen whales or snakes.
5. The Reader will read the summary sentences out loud to the group for approval.
6. The Recorder will write the summary sentences on the group sheet.
7. The Presenter will “present” the summary to the teacher for approval. If the summary
needs revisions, the teacher will provide explanations to the presenter. The presenter will
“present” the information to the group for revisions. The Presenter must get approval by
the teacher before the group can move to the next step.
8. Each group member will write the summary sentences of their section on the Science of
Evolution Student Notes sheet.
Reading Questions
1. What are homologies? _____________________________________________________
2. How does the development of an embryo provide clues to the evolution of present-day
organisms?
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 4
3. What evidence supports the idea that snakes evolved from a limbed ancestor?
__________________________________________________________________________
__________________________________________________________________________
4. What evidence supports the idea that baleen whales share a common ancestor with
toothed whales?
__________________________________________________________________________
__________________________________________________________________________
5. How do cellular and molecular evidence support the claim of common ancestry?
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 5
Understanding the history of life on Earth requires a grasp of the depth of time and breadth of
space. We must keep in mind that the time involved is vast compared to a human lifetime and
the space necessary for this to occur includes all the water and land surfaces of the world.
Establishing chronologies, both relative and absolute, and geographic change over time are
essential for viewing the motion picture that is the history of life on Earth.
Chronology
The age of the Earth and its inhabitants has been determined through two complementary
lines of evidence: relative dating and numerical (or radiometric) dating.
Relative dating places fossils in a sequence
by noting their positions in layers of rocks,
known as strata. As shown in the diagram,
fossils found in lower strata were typically
deposited first and are deemed to be older
(this principle is known as superposition).
Sometimes this method doesn't work, either
because the layers weren't deposited
horizontally to begin with, or because they
have been overturned.
If that's the case, we can use other methods
to date fossil-bearing layers relative to one
another.
By studying and comparing strata from all
over the world we can learn which came first
and which came next, but we need further
evidence to ascertain the specific, or
numerical, ages of fossils.
Numerical dating relies on the decay of
radioactive elements, such as uranium,
potassium, rubidium and carbon.
Very old rocks must be dated using volcanic material. By dating volcanic ash layers both
above and below a fossil-bearing layer, as shown in the diagram, you can determine "older
than X, but younger than Y" dates for the fossils.
Sedimentary rocks less than 50,000 years old can be dated as well, using their radioactive
carbon content. Geologists have assembled a geological time scale on the basis of numerical
dating of rocks from around the world.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 5
Geography
The distribution of living things on the globe provides information about the past histories of
both living things and the surface of the Earth. This evidence is consistent not just with the
evolution of life, but also with the movement of continental plates around the world-otherwise
known as plate tectonics.
Marsupial mammals are found in the
Americas as well as Australia and New
Guinea, shown in brown on the map at right.
They are not found swimming across the
Pacific Ocean, nor have they been
discovered wandering the Asian mainland.
There appear to be no routes of migration
between the two populations.
How could marsupials have gotten from their
place of origin to locations half a world away?
Fossils of marsupials have been found in the
Antarctic as well as in South America and
Australia. During the past few decades
scientists have demonstrated that what is
now called South America was part of a large
land mass called Gondwana, which included
Australia and Antarctica.
Marsupials didn't need a migration route from
one part of the world to another; they rode
the continents to their present positions.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 5
Chronology and Geography
Group Members: ____________________________________________________________
Directions: Each group member will have a specific role in this task. Identify below which
group member will be responsible for each role. Then, follow the steps:
Reader ____________________________
Recorder ___________________________
Timer _______________________________
Presenter ___________________________
1. Each group member will first read the information and the reading questions silently. The
Timer will make sure that no more than 5 minutes is spent reading silently. However, if
everyone is finished reading, the group can move to the next step.
2. The Reader of the group will read the information out loud to the group. During this time,
group members should be following along as well as looking for answers to the
designated questions.
3. After reading, the group should discuss and identify answers to the reading questions.
When the group is in agreement on correct answers, the Recorder will write the answers
to the questions on the group sheet. The Timer will make sure that no more than 10
minutes is spent answering questions. However, if the group finishes before 10 minutes,
the group can move to the next step.
4. The group will write 2-3 sentences summarizing their information. Use the answers to the
reading questions for the basis of your summary. However, the summary sentences
should NOT include specific fossil names or specific fossil information. Ex. Explain fossil
evidence without using marsupial mammals.
5. The Reader will read the summary sentences out loud to the group for approval.
6. The Recorder will write the summary sentences on the group sheet.
7. The Presenter will “present” the summary to the teacher for approval. If the summary
needs revisions, the teacher will provide explanations to the presenter. The presenter will
“present” the information to the group for revisions. The Presenter must get approval by
the teacher before the group can move to the next step.
8. Each group member will write the summary sentences of their section on the Science of
Evolution Student Notes sheet.
Reading Questions
1. What is relative dating? ____________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 5
2. Explain how relative dating is used. Why doesn’t this always work? __________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
3. On what does numerical dating rely? __________________________________________
__________________________________________________________________________
4. How is volcanic material used to date very old rocks? ____________________________
__________________________________________________________________________
__________________________________________________________________________
5. Explain how geography can provide information about the past histories of both living
things and the surface of the Earth.
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 6
Although the history of life is always in the past, there are many ways we can look at presentday organisms, as well as recent history, to better understand what has occurred through
deep time. Artificial selection in agriculture or laboratories provides a model for natural
selection.
Present-day Examples: Artificial Selection
Artificial selection provides a model that helps us understand natural selection. People have
been artificially selecting domesticated plants and animals for thousands of years. These
activities have amounted to large, long-term, practical experiments that clearly demonstrate
that species can change dramatically through selective breeding.
Broccoli and brussels sprouts bear little superficial
resemblance to their wild mustard relatives (right).
If domesticated dogs were discovered today they would be classified as hundreds of different
species and considered quite distinct from wolves. Although it is probable that various breeds
of dogs were independently domesticated from distinct wild dog lineages, there are no wolf
relatives anywhere in the world that look much like dachshunds or collies.
These observations demonstrate that selection has profound effects on populations and has
the ability to modify forms and behaviors of living things to the point that they look and act
very unlike their ancestors. Artificial selection provides a model that helps us understand
natural selection. It is a small step to envision natural conditions acting selectively on
populations and causing natural changes.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 6
Present-day Examples: Ecology
The environment affects the evolution of living things. As predicted by evolutionary theory,
populations evolve in response to their surroundings. In any ecosystem there are finite
opportunities to make a living. Organisms either have the genetic tools to take advantage of
those opportunities or they do not.
House sparrows arrived in North America from
Europe in the nineteenth century. Since then, genetic
variation within the population and selection in
various habitats, have allowed them to inhabit most
of the continent.
House sparrows in the north are larger and darker
colored than those in the south. Darker colors absorb
sunlight better than light colors and larger size allows
less surface area per unit volume, thus reducing heat
loss — both advantages in a cold climate.
This is an example of natural selection acting upon a
population, producing micro-evolution on a
continental scale.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 6
Present-day Examples: Artificial Selection and Ecology
Group Members: ____________________________________________________________
Directions: Each group member will have a specific role in this task. Identify below which
group member will be responsible for each role. Then, follow the steps:
Reader ____________________________
Recorder ___________________________
Timer _______________________________
Presenter ___________________________
1. Each group member will first read the information and the reading questions silently. The
Timer will make sure that no more than 5 minutes is spent reading silently. However, if
everyone is finished reading, the group can move to the next step.
2. The Reader of the group will read the information out loud to the group. During this time,
group members should be following along as well as looking for answers to the
designated questions.
3. After reading, the group should discuss and identify answers to the reading questions.
When the group is in agreement on correct answers, the Recorder will write the answers
to the questions on the group sheet. The Timer will make sure that no more than 10
minutes is spent answering questions. However, if the group finishes before 10 minutes,
the group can move to the next step.
4. The group will write 2-3 sentences summarizing their information. Use the answers to the
reading questions for the basis of your summary. However, the summary sentences
should NOT include specific fossil names or specific fossil information. Ex. Explain fossil
evidence without using brussel sprouts and House Sparrows.
5. The Reader will read the summary sentences out loud to the group for approval.
6. The Recorder will write the summary sentences on the group sheet.
7. The Presenter will “present” the summary to the teacher for approval. If the summary
needs revisions, the teacher will provide explanations to the presenter. The presenter will
“present” the information to the group for revisions. The Presenter must get approval by
the teacher before the group can move to the next step.
8. Each group member will write the summary sentences of their section on the Science of
Evolution Student Notes sheet.
Reading Questions
1. How does artificial selection serve as a model for natural selection? _________________
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 6
2. What examples of artificial selection were described? ____________________________
__________________________________________________________________________
__________________________________________________________________________
3. How does environment affect the evolution of living things? ________________________
__________________________________________________________________________
4. Why are House Sparrows larger and darker in the North than the South? _____________
__________________________________________________________________________
__________________________________________________________________________
5. How is the House Sparrow an example of natural selection acting upon a population on a
continental scale?
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 7
Although the history of life is always in the past, there are many ways we can look at presentday organisms, as well as recent history, to better understand what has occurred through
deep time. Experiments demonstrate selection and adaptive advantage. And we can see
nested hierarchies in taxonomies based on common descent.
Present-day Examples: Experiments
Experiments show that populations can evolve. John
Endler of the University of California has conducted
experiments with the guppies of Trinidad that clearly
show selection at work.
The scenario: Female guppies prefer colorful males for
mating purposes. Predatory fish also "prefer" colorful
males, but for a less complimentary purpose — a
source of food that is easy to spot. Some portions of
the streams where guppies live have fewer predators
than others and in these locations the males are more
colorful (top frame). Not surprisingly, males in locations
where there are more predators tend to be less colorful
(bottom frame).
When Dr. Endler transferred predatory fish to the
regions with brightly colored male guppies, selection
acted rapidly to produce a population of duller males.
This demonstrates that persistent variation within a
population provides the raw material for rapid evolution
when environmental conditions change.
Present-day Examples: Nested Hierarchies
Evolution predicts that living things will be related to one
another in what scientists refer to as nested hierarchies.
Groups of related organisms share suites of similar
characteristics and the number of shared traits increases
with relatedness. This is indeed what we observe in the
living world and in the fossil record and these
relationships can be illustrated as shown to the right.
In this phylogeny, snakes and lizards share a large
number of traits as they are more closely related to one
another than to the other animals represented. The same
can be said of crocodiles and birds, whales and camels,
and humans and chimpanzees. However, snakes, lizards,
birds, crocodiles, whales, camels, chimpanzees and
humans all share some common traits.
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 7
Present-day Examples: Experiments and Nested Hierarchies
Group Members: ____________________________________________________________
Directions: Each group member will have a specific role in this task. Identify below which
group member will be responsible for each role. Then, follow the steps:
Reader ____________________________
Recorder ___________________________
Timer _______________________________
Presenter ___________________________
1. Each group member will first read the information and the reading questions silently. The
Timer will make sure that no more than 5 minutes is spent reading silently. However, if
everyone is finished reading, the group can move to the next step.
2. The Reader of the group will read the information out loud to the group. During this time,
group members should be following along as well as looking for answers to the
designated questions.
3. After reading, the group should discuss and identify answers to the reading questions.
When the group is in agreement on correct answers, the Recorder will write the answers
to the questions on the group sheet. The Timer will make sure that no more than 10
minutes is spent answering questions. However, if the group finishes before 10 minutes,
the group can move to the next step.
4. The group will write 2-3 sentences summarizing their information. Use the answers to the
reading questions for the basis of your summary. However, the summary sentences
should NOT include specific fossil names or specific fossil information. Ex. Explain fossil
evidence without using guppies or other organisms.
5. The Reader will read the summary sentences out loud to the group for approval.
6. The Recorder will write the summary sentences on the group sheet.
7. The Presenter will “present” the summary to the teacher for approval. If the summary
needs revisions, the teacher will provide explanations to the presenter. The presenter will
“present” the information to the group for revisions. The Presenter must get approval by
the teacher before the group can move to the next step.
8. Each group member will write the summary sentences of their section on the Science of
Evolution Student Notes sheet.
Reading Questions
1. Why were more colorful male guppies found in some portions of the stream but not in
others?
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Group 7
2. How did Dr. Endler produce a population of duller males throughout the stream?
__________________________________________________________________________
__________________________________________________________________________
3. What factor can cause rapid evolution? ________________________________________
4. What does a nested hierarchy illustrate? _______________________________________
__________________________________________________________________________
__________________________________________________________________________
5. What did the phylogeny diagram demonstrate? _________________________________
__________________________________________________________________________
__________________________________________________________________________
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Answer Key
Group 1: Fossil Evidence
1. What does fossil evidence show? life is old and has changed over time.
2. What is a problem with fossil evidence? It is not always clear and it can have missing pieces
3. What did the early fossil discoveries described demonstrate? that many fossils represent forms of
life that are no longer with us today
4. What example was used from the fossil record to indicate interaction between once living
organisms? punctures on an ammonite fossil that are believed to be bite marks of a Mosasaur, a
once living marine reptile
5. What evidence from the fossil record was used to provide clues at the cellular level of once-living
organisms? empty spaces in a fossil thigh bone of a duckbill dinosaur Maiasaura which showed that
it had lots of blood vessels that indicates a fast-growing bone
Group 2: Transitional Forms
1. What are transitional forms? fossils or organisms that show the intermediate states between an
ancestral form and that of its descendants
2. Transitional forms are evidence of change over time.
3. Although Pakicetids were land mammals, how is it clear they are related to whales and dolphins?
based on a number of specializations of the ear relating to hearing
4. What demonstrates that an intermediate form existed between the Pakicetus and today’s Gray
Whale? Pakicetus has nostrils at the front of the skull whereas the Gray Whale has nostrils at the
top of the skull
5. What do the transitional forms of horse fossils demonstrate about horse evolution over time?
there was a reduction of toes on horses over time
Group 3: Homologies: Anatomy
1. What are homologies? similar characteristics due to relatedness
2. How does homology demonstrate that frogs, birds, rabbits, lizards, and the transitional form
Eusthenopteron share a common ancestor? their forelimbs share the same bones-the humerus, the
radius, and the ulna
3. How are vestigial features a homology? vestigial features are inherited from ancestors and show
relatedness even though the vestigial features are less functional
4. What evidence suggests that bird ancestors had clawed hands? Hoatzin chicks have claws on
their wings as do some chickens and ostriches
5. How does homology demonstrate that whales and hummingbirds come from a common
ancestor? except for bones that have been lost over time, nearly every bone in each corresponds to
an equivalent bone in the other
Group 4: Homologies: Developmental Biology
1. What are homologies? similar characteristics due to relatedness
2. How does development of an embryo provide clues to the evolution of present-day organisms?
during some stages of development, organisms exhibit ancestral features in whole or incomplete
form
3. What evidence supports the claim that snakes evolved from a limbed ancestor? some species of
snakes have hind limb-buds as early embryos but then lose the buds; also evidence from fossils
4. What evidence supports the idea that Baleen Whales share a common ancestor with toothed
whales? Baleen Whales possess teeth in the early fetal stages and lose them before birth
5. How do cellular and molecular evidence support the claim of common ancestry? all organisms
are made of cells which are very similar and are made up of the same substances; additionally,
organisms are made up of the same important molecules
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Lines of Evidence: The Science of Evolution – Answer Key
Group 5: Chronology & Geography
1. What is relative dating? placing fossils in a sequence by noting their positions in layers of rock
2. Explain how relative dating is used. Why does this not always work? Fossils found in lower
layers of rocks were typically deposited first and are deemed to be older. This does not always
work because sometimes the layers were not deposited horizontally or they were overturned.
3. On what does numerical dating rely? the decay of radioactive elements such as uranium,
potassium, rubidium, and carbon
4. How is volcanic material used to date very old rocks? dating volcanic ash layers above and
below a fossil layer “older than…”, but “younger than…” can be determined
5. Explain how geography can provide information about the past histories of both living things and
the surface of the Earth. Fossils such as those of marsupial mammals have been found on
different continents but not in oceans which suggests the continents were once joined together
Group 6: Artificial Selection & Ecology
1. How does artificial selection serve as a model for natural selection? artificial selection amounts
to large, long-term practical experiments that demonstrate species can change dramatically
through selective breeding; artificial selection illustrates natural conditions acting selectively on
populations causing natural changes
2. What examples of artificial selection were described? Broccoli and Brussels sprouts not
resembling wild mustard; domesticated dogs having so many different species that are very
different from wolves
3. How does environment affect the evolution of living things? populations evolve in response to
their surroundings
4. Why are House Sparrows larger and darker in the North than the South? Darker colors absorb
sunlight better and larger size reduces the amount of heat loss-both advantages in a cold climate
5. How is the House Sparrow an example of natural selection acting upon a population on a
continental scale? Genetic variation within the population and selection in various habitats has
allowed the House Sparrow to inhabit most of the continent
Group 7: Experiments & Nested Hierarchies
1. Why were more colorful male guppies found in some portions of the stream but not others? there
were less predators in those areas to spot and eat the more colorful guppies
2. How did Dr. Endler produce a population of duller males throughout the stream? by introducing
predatory fish to the areas with brightly colored male guppies
3. What factor can cause rapid evolution? environmental conditions change
4. What does a nested hierarchy illustrate? that groups of related organisms share characteristics
and the more closely related organisms are, the more traits they share
5. What did the phylogeny diagram demonstrate? snakes, lizards, birds, crocodiles, whales,
camels, chimpanzees and humans all share common traits
Adapted from Understanding Evolution from http://evolution.berkeley.edu/evolibrary/article/lines_01
Shows interaction
among organisms
Clues at
cellular level
Selective
breeding
Incomplete
Genetic
Engineering
Fossil
Evidence
Artificial
Selection
# of shared traits
shows relatedness
Unclear
Nested
Hierarchies
Transitional
Forms
Present-day
Examples
Ecology
Fossils that
connect ancestors
Science of
Evolution
Environment
impacts
Experiments
Similar physical
features
Anatomy
Similar
Characteristics
(Homologies)
Numerical
Dating
Vestigial
features
Similar bone
structures
Similar features
during development
Humans
changing
conditions
Development
Similar
molecules
Decay of radioactive
elements
Similar cells
Chronology
& Geography
Relative
Dating
Same fossils
different continents
Sequence by
rock layers
Artificial
Selection
Fossil
Evidence
Nested
Hierarchies
Transitional
Forms
Present-day
Examples
Ecology
Science of
Evolution
Experiments
Anatomy
Similar
Characteristics
(Homologies)
Numerical
Dating
Chronology
& Geography
Relative
Dating
Development
Name _______________________________________________ Blk ______
Science of Evolution Graphic Organizer
Word Bank
Use this list for Fossil Evidence and Similar Characteristics:
Incomplete
Shows interaction among organisms
Similar cells
Similar bone structures
Unclear
Similar physical features
Similar molecules
Fossils that connect ancestors
Clues at cellular level
Similar features during development
Vestigial features
Use this list for Present-day Examples and Chronology & Geology:
Selective breeding
Humans changing conditions
Genetic Engineering
Decay of radioactive elements
Environment impacts
Same fossils different continents
Sequence by rock layers
# of shared traits shows relatedness
Name _______________________________________________ Blk ______
Fossil
Evidence
Present-day
Examples
Science of
Evolution
Similar
Characteristics
(Homologies)
Chronology
& Geology
Name ______________________________________________ Blk _____
Science of Evolution Graphic Organizer
Word Bank
Unclear
Clues at cellular level
Ecology
Transitional Forms
Anatomy
Nested Hierarchies
Incomplete
Environment impacts
Experiments
Similar bone structures
Development
Similar physical features
Similar cells
Sequence by rock layers
Relative Dating
Humans changing conditions
Selective breeding
Decay of radioactive elements
Genetic Engineering
Fossils that connect ancestors
Artificial Selection
Same fossils different continents
Vestigial features
# of shared traits shows relatedness
Numerical Dating
Shows interaction among organisms
Similar molecules
Similar features during development
Name ______________________________________________ Blk _____
Fossil
Evidence
Present-day
Examples
Science of
Evolution
Similar
Characteristics
(Homologies)
Name _________________________________________ Blk ___________
Chronology
& Geography