Station 1– DNA Evidence

Cytochrome-c is a protein found in the mitochondria that is used in cellular respiration. This protein consists of a chain of 104 amino acids. The chart below shows the amino acid sequence for cytochrome-c of five vertebrates.

Animal Amino Acid Sequences in Cytochrome-C

Horse gln pro phe thr thr ala lys asn lys thr lys glu glu thr leu met glu lys ala thr asn glu

Shark gln gln phe ser thr asp lys ser lys thr gln gln glu thr leu arg ile lys thr ala ala ser

Human gln pro tyr ser thr ala lys asn lys ile gly glu asp thr leu met glu lys ala thr asn glu

Turtle gln glu phe ser thr glu lys asn lys thr gly glu asp thr leu met glu asp ala thr ser lys

Monkey gln pro tyr ser thr ala lys asn lys thr gly glu asp thr leu met glu lys ala thr asn glu

A. Compare the amino acid sequence of human cytochrome-c with that of the other four vertebrates.

For each vertebrate, count the number of amino acids that differ from those in the human.

Write the number in the data table on your student page. Then answer the questions below the data table on your student page.

B. Based on the data, list the order in which these vertebrates are related to humans using the data table on your student page. Place the vertebrates more similar to humans in sequence from the top.

Station 2 – Embryology

Can you tell a chicken from a fish? How about a human from a pig? Sure you can, you say. Chickens have wings, fish have fins, humans have arms and pigs have hoofs. But what about when they are just starting to form? The drawings below represent three developmental stages of five different animals. They have been all mixed up -- see if you can tell what's what.

Procedure

1. Arrange the squares with your group members and see if you can correctly match the embryos with the animals, placing them in order from earliest to latest stages of development.

2. Fill in the chart on your student page with the number that is on the card.

3. Answer the questions below the chart on your student page.

Station 3 – Homologous Structures

Procedure:

1. Color the homologous bones on your student page according to the color scheme below:

Green = humerus Red = radius Blue = ulna Yellow = metacarpals Purple = phalanges

2. Answer the questions on your student page.

Station 4 –Phylogenetic TreesA phylogenetic tree is a diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor. The trees have branches, the length of which is proportional to the hypothesized time between the divergence of the organisms. Each node at the fork represents a common ancestor.

1. Look at organisms B, C, and D. These are organisms that can be found in present time. Sequence the common ancestors shown from oldest to most current. 2. Look at organisms B and C. They share three common ancestors, X, A, and Z. How many common ancestors do organisms D and B share?

3. Which of the present day organisms are the most closely related?

Station 5 –Cladograms

What is a cladogram? It is a diagram that depicts evolutionary relationships among groups. It is based on phylogeny, which is the study of evolutionary relationships.

Cladistics form of analysis that looks at features of organisms that are considered "innovations", or newer features that serve some kind of purpose. (Think about what the word "innovation" means in regular language.) These characteristics appear in later organisms but not earlier ones and are called derived characters.

Procedure

1. Examine the sample cladogram, each letter on the diagram points to a derived character, or something different (or newer) than what was seen in previous groups. Match the letter to its character on your student data sheet. Note: This cladogram was created for simplicity and understanding, it does not represent the established phylogeny for insects and their relatives.

2. To make a cladogram, you must first look at the animals you are studying and establish characteristics that they share and ones that are unique to each group. For the animals on the table, indicate whether the characteristic is present or not. Create a cladogram like the one pictured above. (Write the name of the organism only. You do not need to draw a picture of the organism. Replace the letters with the characteristic.)

  Cells Backbone Legs Hair Opposable Thumbs Slug (snail)          Catfish          Frog          Tiger          Human          

Station 7–Biogeography

Biogeography is the study of the distribution of species across the globe. Scientists refer to biogeography as evidence of evolution. Species that developed from a common ancestor are usually found geographically near each other.

Procedure:

1. Compare the appearance of the six penguins. Record your observations in the data table on your student handout.

2. Write the letter for each penguin on the map according to their given latitude and longitude.

3. Answer the questions that follow on your student data sheet.

Station 6-Fossil Evidence for Evolution

Paleontology: Scientists use the fossil record as a way to determine the age of fossils and to show evidences of evolution. There are two ways of dating fossils: Relative dating and absolute dating. Relative dating uses a fossil’s location in rock layers to determine a fossil’s approximate age. Fossils found deeper in the ground are usually the oldest. Using the chart to the right, a paleontologist can therefore know that a fossil found in layer 1 at the dig site is older than a fossil found at layer 6. Absolute dating determines the fossil’s actual age by measuring the amount of an element called carbon-14 in the fossil. There is a mathematical formula that will calculate the rate of decay of this element. By measuring the carbon-14 levels and plugging it into the math formula, the scientist can know an actual number of years old a fossil is.

Answer the questions 1-5 on your student data sheet.

Study the picture of the evolution of the horse to the right to complete the CER.

Claim: How has the horse evolved over time?

Evidence: Use two pieces of evidence from the diagram to the left.

A. B.

Student Data Sheet

Station 1

1. Using the amino acid differences, which organism is most closely related to humans?

2. Using the amino acid differences, which organism is least closely related to humans?

Station 2

Stages Lizard Tortoise Pig Human

Early Embryo

Middle Embryo

Late Embryo

1. Based on embryological development, which organism has the most recent common ancestor with the lizard?

2. Which organism has the most recent common ancestor with the human?

Station 3

1. Do homologous structures have the same function in different organisms?

2. What do homologous structures have in common?

3. Are the wings of a butterfly and the wings of a bat homologous or analogous structures? Explain.

Station 4

1. How many common ancestors do organisms D and B share?

2. Which of the present day organisms are the most closely related?

3. According to the phylogenetic tree, which organisms are extinct?

Station 5

1. ______ Wings2. ______ 6 legs3. ______ Segmented body4. ______ Double set of wings5. ______ Jumping legs6. ______ Crushing mouthparts7. ______ Legs8. ______ Curly antennae Draw your cladogram below.

Station 6

1. What are two ways of finding the age of a fossil?

2. Describe how relative dating works?

3. What does absolute dating do?

4. Why is the element carbon-14 important for paleontologists?

5. Which layer has the oldest fossils?

Claim:

Evidence:

Station 7

Penguin Distinguishing Characteristics

Most similar to:

African penguin

Galapagos penguin

Humboldt penguin

Chinstrap penguin

Adelie penguin

Gentoo penguin

1. Do your observations support biogeography as an evidence of evolution? Explain.