Name: ______________________________ Date:__________

Station Lab: Examining the Evidence for

Evolution(Write your answers in complete sentences)

Directions: The goal of this investigation is to learn about the various lines of evidence that

support macroevolution; evolution changes on a long-term timescale. Examples of the different

types of evidence are presented in stations around the room. You see, scientists don’t have

video footage with the story of how life came about, or a textbook that fell from the sky

describing how life has changed on earth over time. Instead, scientists have the very difficult

task of using the clues around them that have been left by past organisms in order to deduce

how organisms evolved, and their relationship to one another.

You must visit each lab table in the room, and figure out how the objects and information

at the table provide evidence for macroevolution. This packet will help to guide you through.

You can begin at any table around the room. Rotate clockwise.

Station 1: Fossil Evidence

(Optional materials: Human Skull, Ancient hominid skull, yard stick)

Fossils are the preserved remains of deceased organisms. They can be skeletons or

impressions, and they are usually found in sedimentary rock (rock that forms in layers over

millions of years. The fossil record shows the history of how species change over millions of

years.

Sedimentary rock forms as bits of earth are compressed over thousands of years or more,

forming rock. Layer after layer compacts on top of each other over millions of years, forming

many layers of rock. As organisms die, they can become preserved in the layer of sedimentary

rock being formed, which preserves and protects them for millions of years.

1. According to the picture above, which layer contains:

a. The oldest fossils? ______________________

b. The most recent fossils? __________________

2. How can the fossils found in each layer show scientists how life has changed over time?

3. Examine the skull(s) on the lab table (if you do not have any actual skulls at the table, just

refer to the image below) One is the skull of a modern human being, like yourself, and the

other is of an ancient primate fossil named Afarensis. CAREFULLY turn the skulls upside down,

and examine the hole on the bottom. Note its position. This hole is called the foramen

magnum, and this is where your spinal cord comes out of, connecting your brain to the rest of

your body. The picture below shows the position of the foramen magnum of three different

species of primates: modern day gorilla, Australopithecus africanus (2-3 million year old

primate), and modern human.

A. Write the name of the hominid species in the order of position of the foramen magnum; from

the farthest position on the back of the skull, to the most forward location on the skull.

1._______________ 2._______________ 3._______________ 4._______________

(Farthest back of head) (closest to front of skull)

B. What could the position of the Foramen Magnum tell you about how each species walked?

(hint: If you have a skull in front of you, sometimes it helps to CAREFULLY insert a meter stick

in the foramen magnum, to visualize the angle at which the spinal column comes out.)

C. Based on the position and function of the foramen magnum, predict where the FM is located

in the following organisms. Draw on the skull models to the right to show where they would be

located. (the black ovals represent where the eyes would be)

A. Domesticated Dog -

B. Boa Constrictor -

C. Kangaroo -

D. Most people have seen some version of the image below (to the right), showing the evolution

of the upright-walking humans from more hunched-over ancestors. Examine the diagram of

hominid (human-like) fossils, and then describe why the evidence supports the diagram to right.

Station 2: DNA / Molecular Evidence(Materials: Human DNA graphic, DNA% circles for 12 organisms)

Every organism on the planet contains DNA, from bacteria, plants, fungus, to humans. We all

share the same type of chemical instructions.

A. If scientists were to sequence (figure out the code) your DNA, and compare that to your

sibling's, and your friend's DNA, who would have DNA closer in sequence to yours? Justify

your response.

B. The graphic on the table shows a person’s DNA, and 12 different locations on the DNA,

representing percentages of the total DNA that is shared between an organism and a human.

Your task is to match the organism listed on the circle to the correct percent DNA shared

between that organism and humans. DO NOT LIFT THE FLAP UNTIL YOUR GROUP IS DONE

WITH arranging the circles.

C. What does the percentage of DNA shared between an organism and a human tell you about

the relatedness of the organism. Use at least two organisms, and percentages, in your

response.

D. ALL organisms on Earth contain DNA as their chemical “instruction manual”. How does this

fact provide evidence for the fact that all organisms share a distant common ancestor?

Station 3: Embryological Evidence(Materials Needed: Embryo Poster)

*DO NOT LIFT THE FLAPS ON THE POSTER, and DO NOT READ AHEAD FOR THIS

LAB TABLE ACTIVITY*

An embryo is what we call an organism early on during development. We call humans embryos

from when fertilization occurs up until eight weeks of development. Almost all multicellular

organisms exist as an embryo for some period of time.

1. Lift the first flap, on the top of the poster. What do you see? Compare/Contrast the

specimens.

2. You are looking at eight embryos. Each embryo will become a mature vertebrate.

Vertebrates are organisms with backbones. The embryos will become a pig, turtle,

rabbit, cow, salamander, human, chicken, and fish. Can you tell, at this stage, which

embryo is which (they aren’t in the order I listed)? List your guesses on the lines below.

Flap 1 guesses:

1._______ 2. _______ 3. _______ 4. _______ 5. ________ 6. ________ 7. ________ 8. ________

3. Lift flap 2. Flap 2 shows the same embryos, but now they are further in development.

How are the embryos different from the first image? Is it easier to tell them

apart? List your guesses again below.

Flap 2 guesses:

1._______ 2. _______ 3. _______ 4. _______ 5. ________ 6. ________ 7. ________ 8. ________

4. Lift flap 3. Flap 3 shows the same embryos, but now they are even farther in their

development. List your guesses again below.

Flap 3 guesses:

1._______ 2. _______ 3. _______ 4. _______ 5. ________ 6. ________ 7. ________ 8. ________

5. Lift flap 4. Flap 4 shows the answers to your guesses. Were your guesses more accurate

for the later stages of the embryos? ___________. Make a generalization about how

vertebrate embryos start out, and what happens during development.

6. How can scientists use vertebrate embryo development to build evidence for the claim

that vertebrates are somewhat closely related in the evolutionary history of life on

earth? Incorporate your answers from the two questions above. Explain.

7. There are folds labeled “Gill Arches” in the first image of the embryos. How many gill

arches does each embryo begin development with? ________. In fish and salamanders,

the gill arches become internal and external gills in the adults. In the land vertebrates,

they become parts of the mouth, muscles in the head and neck, and parts of their throat.

Why do they start out the same, but develop into very different structures? Explain.

Station 4: Vestigial Structures(Materials: String, ruler, possibly ancient primate skull)

Archeologists (study fossils) have found many skull fossils of primates/ humanoids that

date back from thousands, to even millions, of years ago. They measure the length of the

mandible (jaw bone) from where it hinges in the back to the chin, and then up to the other side,

where it hinges. Located on your table is a replica of the skull of one of these ancient primates,

Measure the length of its mandible using the materials provided. Note: If you don't have a

skull at your desk, assume the length of the mandible is 11.5 inches.

1. Length of Australopithecus africanus mandible _________________ inches

Use the materials provided (string, ruler, your mandible) to calculate the average length of the

mandible for the people in your lab group. SUBTRACT 0.5 inches from the average, to account

for the fact that skin and muscle cover your mandible.

2. Average length of your lab group’s mandible: _________________ inches. (don't forget

to subtract 0.5 inches)

3. How do human mandibles compare to ancient primate mandibles?

4. Your mandible, like the mandibles of ancient primates, helps you digest food by grind your

teeth together to break up food. Count the number of bottom teeth you have {include

wisdom teeth (even if you have had them removed, count them in)}. Average the number

of bottom teeth for the humans at your lab table.

Average number of bottom teeth

(including wisdom teeth that were removed) _______________ teeth

5. By counting up all the teeth (and missing teeth holes) in the ancient primates jaws’,

archeologists found that, on average, ancient primates had 16 teeth on the bottom.

Compare the amount teeth per inch of mandible that you have by filling in the chart

below. INCLUDE YOUR WISDOM TEETH, EVEN IF THEY WERE REMOVED.

Average # of teeth

on bottom jaw

Average length of

bottom jaw (inches)

Average number of

teeth per inches of

space of bottom jaw

(teeth/inch)

Human (Average)

Ancient Primates

6. What is your conclusion? Do modern humans, or ancient primates, have more room for

teeth in their mouth? Explain.

7. Many humans have the misfortune of wisdom teeth. Wisdom teeth are molars, found all

the way in the back of your mouth that can cause a person pain and problems because

there is not enough room in your mouth to comfortably fit wisdom teeth. Thanks to

modern dentistry, these annoying “extra teeth” can be removed. What is a possible

explanation for why we have these extra teeth? (hint: Could ancient primates fit these

teeth into their mouths’?)

Station 5: Homologous Structures(Optional materials: mini human skeleton, cat skeleton, chicken skeleton)

1: Explain how each of the following organisms specifically use their limbs.

A. Human’s arm - _______________________________________________________

__________________________________________________________________

B. Dog's front leg - ______________________________________________________

__________________________________________________________________

C. Bird's wing -_____________________________________________________

__________________________________________________________________

D. Whale's front fin - ___________________________________________________

__________________________________________________________________

2. Do these organisms use their front limbs (forelimbs) for the same function? Explain.

3. Now, let’s examine the skeletal anatomy of these forelimbs by looking at the bones in each.

Using the human skeleton model, and the cat skeleton model, compare the bones of the

Forelimbs. If you don't have skeletons in front of you, then use the pictures on the table.

How are the bones arranged similarly? Differently?

4. If they have such different functions (gripping, flying, swimming, running), then why are the

bones arranged so similarly? Explain why the arrangement of bones in these animals is so

similar.(like cats, dogs, bats, and even whales). Hint: from where did all these organisms likely

inherit these bones? Incorporate your answers from the previous question.

Lab Table 6: Convergent & Divergent Evolution

(Materials: Pictures of organisms)

1. In your own words, define the words converge, and diverge.

Converge: __________________________________________________________

Diverge: ___________________________________________________________

2. Next, examine the image of the humming bird, and humming bird moth on your table, and

answer the following questions:

A. Describe, in a list, all of the SIMILARITIES that you see between the bird and moth.

B. Are birds and insects (like this moth) closely related groups of organisms? Explain.

3. Next, examine the image of the salmon, dolphin, and ichthyosaur on your table, and

answer the following questions:

A. Describe all of the SIMILARITIES that you see between the salmon, dolphin and

ichthyosaur.

B. Are dolphins, fish, and dinosaurs closely related groups of organisms? Explain.

4. CONVERGENT EVOLUTION explains the patterns that you saw with the organisms on

the previous page. Write a definition for convergent evolution below.

5. The humming bird is a vertebrate, with bones arranged like yours in its wings. The

hummingbird moth is an invertebrate, and has no bones, but possess wings that are similar in

shape to the hummingbird. The wings of the hummingbird, and wings of the moth, are called

analogous structures, and evolved separately from one another. Why do certain species of

organisms look/behave similar to other organisms, despite the fact that the two species are

not closely related at all?

6. DIVERGENT EVOLUTION works in the opposite way that convergent evolution works.

In other words, divergent evolution occurs when species that are closely related to oneanother have differences in appearance or behavior.

If you look at the graphic of mammals, on the table, you can see that mammals vary greatly

in size, shape, color, and behavior. Yet, despite looking very different, all mammals are arelatively closely related category of animals. The fossil record suggests that the first

mammal appeared only recently (220 million years ago).

What causes closely related species to look so different (hint: what factors influence the

appearance of organisms)?

Provide at least two more examples of divergent evolution (research examples only after

you've tried to come up with some with your lab group first.

Station 1 Materials: Examine any skulls you have at your table. If there are no skulls, then refer to the

image below.

Station 2 Materials: Place the circles with the organism's name on it in the circles arrows below to predict

the percentage of DNA that the organisms share with humans. After your group is satisfied with you

prediction, lift the flap, and answer the questions in your packet.

Station 2 Materials (continued): This page is for the teacher.

Cut these circles out, and leave them at station two for students to make predictions.

Cut out the rectangle, and staple it flap onto the dotted line from previous page (it serves as a flap to hide

the answers).

Flap 4 is on the next page.

Here is a picture of what the poster (with flaps) should look something like.

Station 5 Materials

Station 6 Materials: Convergent Evolution

Station 6 Materials (continued): Convergent Evolution

Station 6 Materials (continued):

Divergent Evolution