Download Evidence of Evolution Lab Stations

EVIDENCE OF EVOLUTION STATIONS
Station 1: Fossil Records
1. First, write the scientific definition of the following key terms in your NB, under the heading
Fossil Records, write definitions in your own words but be sure not to leave out important
parts.
Fossil __________________________________________________________________________
Sedimentary rock _________________________________________________________________
Natural selection__________________________________________________________________
Next, examine the
diagram (left) to
answer the
questions below in
complete
sentences.
2. Explain what
this diagram is
communicating.
3. Is this
diagram showing
direct evidence
or an inference
based on
reasoning?
Explain.
This diagram shows insects and a
lizard trapped in fossilized tree sap
(amber) from millions of years ago and
how they look today.
4. Explain how organisms
could not change over time
and natural selection still
be true and happening?
EVIDENCE OF EVOLUTION STATIONS
Which layers are oldest?
Can you put them in order from youngest to oldest?
EVIDENCE OF EVOLUTION STATIONS
Station 7: Descent with modification
Examine the diagrams and descriptions in the table about horse evolution on the back and use that information
to answer the questions in complete sentences in your NB
1. Define: Descent with modification
2. Hyracotherium lived in a dense forest area dominated by a rich undergrowth of ferns.
Discuss why the small body size might be an advantage in this type of environment?
3. A change in vegetation from dense forest to grasslands occurred due to climate changes and
this selected for changes in the shape of the horse’s leg and body size. Explain how these
changes in vegetation could lead to the evolution of the horse.
4. The teeth of the browsers* (such as Mesohippus) were covered with a thick layer of enamel
(hard outer-coating of teeth). The teeth of the modern-day horses, by comparison, have less
enamel and appear to be much wider and flatter. Provide scientific reasoning to explain
these changes seen in horse teeth over time.
*Browsers vs. Grazers: Browsers strip off and eat leaves, bark, and green stems from plants, while grazers clip vegetation like grasses at
or near ground level. Deer, such as white-tailed deer in the Rocky Mountains, are browsers. The disadvantage of browsing is that
height may make vegetation inaccessible (hence the long neck of the browsing giraffe), and often-times browsers eat parts of the
vegetation that are low in nutrients, chemically defended (bitter/poisonous), or both. Grazers, such as sheep and cattle, can feed on the
much more nutrient-rich grasses.
Examine the images of
modern horse variations
at left.
5. All of these
variations have come
about in the last
4,000 to 6,000 years
as humans
domesticated horses
for work, travel, and
show. Explain how all
of these variations
can happen in such a
relatively short period
of time when
previous changes
took millions of
years.
EVIDENCE OF EVOLUTION STATIONS
modern-day horse
Pliohippus
1.6 million years ago
Equus
Time
frame
Diagram
Description of horse
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Hyracotherium
37 million years ago
Mesohippus
24 million years ago
Merychippus
5 million years ago
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This horse lives in the grassy plains area
It eats grasses and is classified as a grazer
It is approximately 1.6 m (5.2 ft.) tall
It has a single visible digit
This horse lived in areas with shrubs and
on the grassy plains
It ate grasses and is classified as a grazer
It was approximately 1.0 m (3.2 ft.) tall
It had a single visible digit
This horse lived in areas with shrubs and
on the grassy plains
It ate leafy vegetation and grasses and is
classified as a grazer
It was approximately 1.0 m (3.2 ft.) tall
It has three visible digits
This horse lived in thinly wooded areas.
It ate leafy vegetation and is classified as
a browser
It was approximately the size of a small
dog, about 0.6m (2 ft.) tall
It had four visible digits
This horse lived in thickly wooded areas
It ate leafy vegetation and is classified as
a browser
It was approximately the size of a small
dog, about 0.4 m (1.3 ft.) tall
It had four visible digits
EVIDENCE OF EVOLUTION STATIONS
Station 2: Vestigial structures
Examine the diagrams and visuals below with your group. Based on your observations and discussion, answer
the following questions in complete sentences.
1. Write a definition of a vestigial structure.
2. Name 3 vestigial organs that humans have and hypothesize what their purpose probably was.
3. Explain why snake legs are vestigial.
4. Explain the scientific reasoning of how a vestigial organ is evidence of evolution.
Snakes evolved from four legged animals similar
to lizards.
Most species of snakes have lost all traces of
limbs but snakes in the boa and python family
have a tiny pair of hind legs.
Unlike whales, the python's (or boa's) vestigial
legs can actually be seen as a pair of "spurs" that
stick out where the body ends and the tail
begins. (Admittedly, it is difficult for an untrained
person to tell where that is!)
The vermiform
appendix had
digestive
functions in the
ancestral human
species, probably
helping the
cellulose in grass
breakdown in the
intestine, as they
were herbivours.
The appendix has
become vestigial
in human beings because they have
become very small in size and don’t
contribute in cellulose fermentation.
However, several appendix problems
occur in people and the removal of this
part in the body will do no harm and is
relatively common.
Whales still have bones (not seen from
outside) that are remnants from hind
legs.
EVIDENCE OF EVOLUTION STATIONS
Station 3: Comparative Anatomy & Homologous Structures
Analyze the diagram above then answer the following questions in complete sentences after discussing with
your group.
1. Describe how the limbs of these seven organisms are similar and how are they different.
2. Explain why they are so similar in structure and yet can be used differently by the organism?
How did this happen?
3. What does this help explain about how related or
not these species are to each other?
4. Explain how these structures are evidence of
evolution.
This picture of bones is from a seal fin I found on the beach. My own
piece of evidence collected from a backpacking trip to the Lost Coast
in Northern California, summer 2013 (Me and a member of the
Pinniped family (seals) both gesturing for world peace).
EVIDENCE OF EVOLUTION STATIONS
Station 4: Comparative Embryology
Examine the diagrams of four
different vertebrate organisms
at the early embryo stage.
Discuss differences with your
group and then answer the
questions in complete
sentences.
1. Try to determine which embryo will develop into which organism- reptile, human, bird, fish.
2. Which ones out of the four do you think are most closely related, and why?
3. After reading the passage below, construct an explanation for which animal is more closely
related to humans- chickens or fish? (put answer in CER format, complete sentences)
Claim:
Evidence:
Reasoning:
EVIDENCE OF EVOLUTION STATIONS
Station 5: Genetic Evidence
Gene sequence & protein sequences comparisons
DNA is the code for making proteins, the closer the DNA, the closer the amino acid sequence, and thus the
closer the final proteins are.
Analyze the following data with your group:
Amino Acid Sequences
Baboon ASN THR THR GLY ASP GLU VAL ASP ASP
Chimp SER THR ALA GLY ASP GLU VAL GLU ASP
Lemur ALA THR SER GLY GLU LYS VAL GLU ASP
Gorilla SER THR ALA GLY ASP GLU VAL GLU ASP
Human SER THR ALA GLY ASP GLU VAL GLU ASP
SER
THR
SER
THR
THR
PRO
PRO
PRO
PRO
PRO
GLY
GLY
GLY
GLY
GLY
GLY
GLY
SER
GLY
GLY
ASN
ALA
HIS
ALA
ALA
ASN
ASN
ASN
ASN
ASN
1. For each primate in the table above, count the number of amino acids that are different from
the human sequence. Record these numbers in a data table on your handout, draw one like
the one shown below.
2. Calculate the percentage of differences of each primate compared to humans by dividing the
number of amino acid differences by 15 and then multiplying by 100. Record these numbers
in the data table you drew as well.
Primate
# of Amino Acids
Different from
Humans
Percent
Difference
Baboon
Chimpanzee
Gorilla
Lemur
3. Use this data to create a graph to better communicate your findings. Remember which graph
type is good for comparing categories? Include title, label each axis with “x” and “y” AND the
label (category/unit), make a key, include an appropriate scale.
4. Are your results surprising? Why or why not?
EVIDENCE OF EVOLUTION STATIONS
Chromosome comparisons:
Another line of genetic
evidence
5. Summarize the argument: what
evidence exists that humans and
great apes shared a common
ancestor?
EVIDENCE OF EVOLUTION STATIONS
Station Six: Biogeography
1. Define Biogeography
2. Define a species
3. How did these three members of the camel family become different species?
Claim:
Evidence:
Reasoning:
EVIDENCE OF EVOLUTION STATIONS
Biogeography Cont.
Endemism is the ecological state of a species being unique to a defined geographic location, such as
an island, nation, country or other defined zone, or habitat type; organisms that are indigenous to a
place are not endemic to it if they are also found elsewhere.
Madagascar—an island off the coast of Africa—has some of the world's most
interesting animals. About 75 percent of the species found in Madagascar are
endemic, found nowhere else on the planet.
1.) What kind of selection would be responsible for giving rise to so many different species on this one island?
Would it be a different kind of selection for just the endemic species? What is doing the selecting?
EVIDENCE OF EVOLUTION STATIONS
Station 8: Evolution of a Scientific Theory
Building Ideas to Explain How Evolution Happens
1.) Science is a communal effort- which scientists laid the foundation
for Darwin’s theory of natural selection? What ideas did they
contribute that were crucial for Darwin to build on? (see back side)
2.) What do we know now about DNA and genetics that further
disproves LaMarck’s theory?
2.) Are humans subject to natural selection? Does our human
population have all 4 required factors?
EVIDENCE OF EVOLUTION STATIONS