Evolution Notes and Activities. Can eyeballs be fossilized? Then, how can we know how ancient animals were able to

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1 Name: Evolution Notes and Activities Day 1 What is meant by evolution? Video: Your Inner Fish Explore Your Inner Animals (click LAUNCH then click on the body parts spin the body to find them all) Head What will you be exploring? Can eyeballs be fossilized? Then, how can we know how ancient animals were able to see? Explain how the position of eye sockets changed over time and why. Legs How are human legs adapted for walking? Back How is our back shaped and what is the reason for that shape? Teeth There is an evolutionary history between teeth and. They all share a common gene, the gene. What is ectodermal dysplasias?

2 Evolution 101 What is biological evolution? What is the central idea of evolution? Mechanisms of Evolution Descent with Modification Evolution only occurs when Which of these 2 scenarios is an example of evolution? Explain your choice. A. Beetles on a diet OR B. Beetles of a different color Mechanisms of Change What are the 4 processes for evolutionary change? Explain each in your own words

3 Genetic Variation What are the sources of genetic variation? Briefly explain each in your own words Stop here for today Day 2 What is genetic drift? What does it need to occur? Genetic Drift Driftworms: GENETIC DRIFT Simulation Evolution (change over time) is how modern organisms have descended from ancient ancestors over long periods of time. It is responsible for the remarkable similarities we see across all life and the amazing diversity of that life. Evolution is often described as "descent with modification." (passing changes down to offspring) Evolution only occurs when there is a change in gene frequency (how often a gene occurs) within a population over time. These resulting genetic differences can be passed on to the next generation over time (i.e., inherited), which is what really matters in evolution - long term change. The major forces of evolution are mutations (changes or errors in DNA), gene flow (immigration and emigration), non-random mating (using criteria to select a mate), natural selection (survival of the fittest) & genetic drift (the disappearance of an allele from a population). These forces cause changes in genotypes (the genetic code) & phenotypes (the physical appearance) over time and also determine the amount & kind of variation seen in a population. Genetic drift is the RANDOM decrease in gene frequency within a population due to the role of "chance" and/or unpredictable "accidents." Small populations that are isolated from one another can differ greatly as a result of genetic drift. The cheetah is a great example. Driftworms have only one gene that controls skin color. These worms reproduce asexually and are connected to their parents by lines. In any population of driftworms, each worm gives rise to exactly one worm in the next generation. It doesn't matter how good your driftworm genes are if you get squished by a shoe before producing offspring!

4 How can alleles disappear? An ant may get stepped on A rabbit may get swept up by a tornado An elephant may drink a parasitic protozoan living in a puddle A plane may crash killing a Nobel Prize winner Procedure 1. On the Driftworm Worksheet, color each of the five worms in Generation 0 (zero) a different color. You may choose the colors. Number the worms 1-5 (top to bottom). 2. Roll the die and put a dot (.) next to the corresponding worm. If you roll a 6, roll again. 3. Repeat Step 2 five times. This is the population size of the worms 4. Starting at the bottom, draw a line from each dot to the bottom-most worm in the next generation. 5. Color the worm(s) in the next generation the same color as its/their parent. 6. Repeat Steps 2-5 until ALL the worms in a generation are the SAME color. This is when that gene s allele is fixed Please be patient since it may take a while. Group data will vary accordingly. (Next page has the worksheet to be completed before these questions) Which gene (allele) became fixed in your gene pool? Why is there no point in adding more generations after an allele (gene) has become fixed? Using your group's data, what was the number of generations until an allele became fixed? Which genes drifted from your gene pool? If the color of your driftworm was determined by the color of the environment it lived in, would the disappearance of all the other colors still be considered genetic drift? Why or Why not?

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6 Video: Lizards in an Evolutionary Tree What made the lizards in the video different species? What caused this to happen? Does environment have anything to do with it? Speciation What is a species? What is speciation? How can speciation occur? 1. isolation - 2. isolation - Stop here for today

7 Day 3 What is natural selection? Natural Selection (Class Activity) WOOLYBOOGER LAB Which Beak is Best? Background: You and your team are crewmembers on the Beagle in Darwin has asked your team to assist him in collecting data on a strange and unusual bird that he has discovered on the Galapagos Islands. He has called this bird the Woolybooger. Darwin and your team search the islands and find three different populations of this creature. During your observations of these three populations, you discover that each group is similar in appearance except for mouth variations. Some Woolyboogers have a knife-shaped mouth, some have a clip-shaped mouth, and some have a tweezer-shaped mouth. All of the birds have migrated to an island that only has dried beans for them to eat and the hours of daylight needed for finding food is steadily decreasing due to the change in seasons. Darwin and your team study the Woolybooger s life on the Galapagos Islands. During your last few months on the islands, you discover a new rare Woolybooger, which has a spoon-shaped mouth. On the Beagle, Darwin and your team discuss which beak type of Woolybooger will survive the best on the island and how the population of Woolyboogers will change over time or evolve. MATERIALS: dried beans knives clothes pin tweezers spoons paper plate (1 per group) cups (1 per person)

8 PROCEDURE: 1. You will run through five trials of feeding by the Woolyboogers. You will be assigned a feeding tool to gather your favorite food, beans. You must use your utensil as demonstrated to capture food. You cannot scoop the beans into the cup, which represents your stomach. You must lift the beans, one at a time, with your utensil. The cup must stay in your hand during feeding. 2. You will be required to capture at least 20 beans in a trial in order to survive. If 20 beans are not captured, your Woolybooger has died. When a Woolybooger dies, in the next trial you will play the role of the offspring of the most successful surviving Woolybooger (the woolybooger capturing the most beans). 3. The first trial will last 1 minute 15 seconds, the second 1 minute, the third 45 seconds, the fourth 30 seconds and the fifth will be 15 seconds. Because Woolyboogers with spoon-shaped mouths are rare, only a few of you will be assigned this tool for the first generation of Woolyboogers. Hypothesis: Which beak do you think will work best? How do you think the Woolybooger population will change over time (evolve)? DATA TABLE: Number of Woolyboogers at beginning of each trial Mouth shape 1 minute 15 seconds 1 minute 45 seconds 30 seconds 15 seconds Final Number Knife Clothespin Tweezer Spoon

9 Describe how the Woolybooger population evolved (changed over time)? How did this compare to your hypothesis from before we ran this simulation? (at least 3 sentences) Which variation of Woolybooger beak was best adapted to survive on the island? Why? What happened to the Woolyboogers who were less adapted to survive on the island? What would be necessary in nature for all the variations of Woolyboogers to be able to coexist and all reproduce without one beating out another? What is a real-life example of the Woolybooger, where one organism has a definite advantage over another organism of the same species? Explain. In what ways was this simulation realistic? In what ways was this simulation unrealistic? Stop here for today

10 Day 4 What is Natural Selection? How does it happen? Video: The Beak of the Finch The Evolution Experience Run the simulation. How did the population of beetles change over time? How many generations did you survive? Why? Natural Selection at Work Here you will see one of the most famous examples of natural selection: The Peppered Moths. Click on The Life Cycle of the Peppered Moth Briefly describe what the Peppered Moth looks like: Who eats peppered moths? What adaptation do moths have that help keep them from getting eaten? What do moths do to prevent death in the colder months? What colors can the peppered moth come in?

11 Click on Impact of Pollution What happened to the peppered moth population by 1900? Why did people think the moths were all of a sudden becoming much darker? Why do you think there were more dark moths than before? Who first proposed Natural Selection? What is natural selection? How are the peppered moths turning from light colored to dark colored and example of natural selection? Why has the number of dark moths decreased in the last 50 years? Click on Bird s Eye View and read the instructions for the Peppered Moth Game Do the light forest first and then you can go back and do the dark forest. The number of dark and light moths was equal when the simulation started. How did the number of dark and light moths compare at the end of the simulation? Why?

12 Go back and do the dark forest simulation. What happened to the number of light and dark moths in this simulation? Why? Explain how the color of the moths increases or decreases their chances of survival. Explain the concept of "natural selection" using your moths as an example. What would happen if there were no predators in the forest? Would the colors of the moths change over time? Defend your answer? Day 5 What are the Galapagos Islands and why are they important? Video: Jeff Corwin and The Galapagos Islands Stop here for today 1. What do scientists say makes the Galapagos Islands unique? A) the different kinds of plants living on the islands B) the large numbers of species living on the islands C) the different animal species living on the islands D) the large numbers of marine iguanas on the islands 2. Which choice BEST explains why each island in the Galapagos has unique kinds of iguanas? A) Iguanas prefer a marine environment. B) Some iguanas are better swimmers than others. C) The species arrived on the islands in different ways. D) The species adapted to each islands unique habitat.

13 3. Sea lion bulls stake out the best territory on the water in order to attract other bulls. A) true B) false 4. Why do Galapagos sharks lie still on the ocean floor? A) They are sleeping. B) They are being social. C) They are waiting for food. D) Scientists still dont know why. 5. Penguins are an unusual species to find in the Galapagos Islands because. A) the islands are tropical and penguins live in very cold regions B) the islands are very cold and the penguins live in tropical regions C) the islands tropical waters dont have an adequate food source for the penguins D) the islands arctic waters can easily cause the penguins to suffer from hypothermia 6. Why is the tortoise breeding program on Santa Cruz Island important? A) The tortoise population has increased. B) No one knows how long a tortoises lifespan is. C) No one knows how two tortoise species became extinct. D) The tortoise population has decreased. 7. Masled boobies lay two eggs. Which of the following does NOT occur when the eggs hatch? A) One egg hatches before the other. B) The parent raises both hatchlings. C) The parent ignores the second hatchling. D) The first hatchling pushes the second one out. 8. Marine iguanas on Espanola Island each show a different coloration of their scales in order to, A) dig nests B) stand out in the sand C) identify their territory D) appear healthy for a mate 9. Why is the giant iguana a good example of Charles Darwins theory of adaptive radiation, or the way a species adapts to its environment? A) Giant iguanas help each other survive. B) Giant iguanas are larger than other iguana species. C) Giant iguanas live on the largest island in the Galapagos. D) Giant iguanas live on the smallest island in the Galapagos.

14 10. If Charles Darwin could return to the Galapagos Island today, which of the following is an example of a change he might see? A) no changes B) more islands C) more tortoises D) new species of iguanas Explain how Natural Selection is evident on the Galapagos Islands. Use at least 1 organism from the video to support your answer. Survival of the Sneakiest Read the cartoon and answer the questions When it comes to crickets, what does fitness mean? Is calling good or bad for a cricket's fitness? Give some examples of selection at work in this cricket story. How does selection favor calling? How does selection favor not calling? Stop here for today

15 Day 6 Who was Charles Darwin? Darwin Stations Station I: England Here we are going to look at some animals that Darwin typically saw around his home in England. Look at the sheet labeled DOGS. 1) A species is a group of organisms that can breed to produce babies. Two elephants can reproduce and have elephant offspring, but an elephant and a chicken cannot reproduce and have a baby chickephant. Are all of these dogs the same species? Why or why not? 2) List three differences between the dogs: ) I have a male and female of each of these dogs. I want to have a dog that is very small and black and has long hair. Which two dogs should I breed? 4) Why do the dogs look so different from one another? 5) Look at the sheet labeled PIGEONS. Do you think that these pigeons are all the same species? Why or why not?

16 Station II: South America 1) What is the main difference between the ground sloth and the three-toed sloth? 2) What is the main difference between the ancient capybara (Phoberomys) and the modern capybara? 3) Darwin found the bones of the ground sloth and what he thought was an ancient capybara in South America. He asked around, but nobody in South America had ever seen either of those animals alive. What had happened to them? 4) List two reasons why that might that have happened

17 Station III: Galapagos Islands 1) When Darwin reached the Galapagos Islands, he saw many of the finches that are shown in the picture. He noticed that they had different-shaped beaks. Why do the different finches have different beak shapes? 2) According to the diagram, what does the Warbler finch eat? 3) These three finches eat seeds. Draw a line between each finch and the seed that it likes to eat. 4) All three of the birds from the previous question live on one island. The island becomes warmer and the hickory trees (that produce hickory nuts) produce fewer nuts. Sunflowers like the heat and more sunflowers grow and produce seeds. What will happen to the population sizes of the birds on the island? Bird A s population will increase / decrease / stay the same (circle one). Bird B s population will increase / decrease / stay the same (circle one). Bird C s population will increase / decrease / stay the same (circle one).

18 Station IV: Australia Look at the paper with the skulls on it. These are two skulls photographed from different angles. All those labeled 1 are from one animal, and those labeled 2 are from another animal. 1) List three ways that skull #1 is similar to skull # ) Look at the picture labeled A. Count the number of teeth on each jaw. The jaw of skull #1 has teeth. The jaw of skull #2 has teeth. 3) List two more differences between the two animals skulls ) What do you think these animals eat? 5) Do you think these two animals are closely related to one another? 6) Skull #1 is from a marsupial wolf and skull #2 is from a gray wolf. Why do you think the skulls look so similar even though the animals are not closely related to each other. Day 7 Who is Charles Darwin? Stop here for today Darwin On the bottom of the main image, click on More about Darwin. What was the name of the ship that Darwin traveled on? Where in the world did Darwin make his most important discoveries? What was the name of Darwin s most famous book?

19 Click on Natural Selection on the top of the main image. Fill in the blanks. Part 1: Every exhibits. Not all members within a are exactly the. What variations can individuals exhibit? Part 2: Many are passed from parents to their. Part 3: Life in the wild is and organisms with the most beneficial will prosper (succeed and reproduce). This is known as. If an organism has traits that help it survive or attract mates, what will it be able to do? Eventually, traits can spread throughout a species. Survival Game: Who wants to live a million years? You will now play this survival game to model evolution. This game is not easy so I would be sure to look at the hints. Also, when the game starts be sure to pay attention to the environment, the years that have gone by, and what hints Darwin gives you. Finally, there is one part of the game called the Life Preserver. This is not accurate as far as evolution is concerned, but will help you win the game. Note: It is difficult to win but not impossible. Notice that there is initially a lot of variation in the population. What are some variations that you see? Choose your population. The animals with most suited to the new will.

20 After the first cycle ( 140,000 years), what has happened to the population of animals? After the second cycle ( years), what has happened to the population of animals? If your animals died (which they probably did), why did they die? Play the game again. How long could you keep your animals alive? Why did some animals die, while others thrived? Why did the physical characteristics (phenotypes) of the overall population change? Now take the Natural Selection Quiz! What was your score? Stop here for today Day 8 Who is Darwin? Who is Lamarck? What are their theories of evolution? Comparing Evolutionary Theories The theory of evolution emerges from different lines of evidence, such as fossil records, modification by descent, and the evidence from biogeography, genetics and other forms of evidence. Jean-Baptiste Lamarck ( ) and Charles Darwin ( ) had different theories about how life on earth got to be the way it is now. Jean-Baptiste Lamarck ( ) Lamarck was a French biologist who is best known for his Theory of Inheritance of Acquired Characteristics, first presented in He believed that evolution was the acquired traits of a species that is inherited by its offspring. His theory was that if an organism continually used a structure to carry out a certain task, the structure used would become physically modified over time to make the task easier. This modified structure would then be passed on to any offspring. For example, if a short-nosed elephant was continually stretching out its trunk to try to reach the leaves high up in trees, it s trunk would stretch and become longer over time, and any babies that it had would be born with longer trunks.

21 Lamarck also believed that when body parts were not being used, such as the human appendix, they gradually disappear. Eventually, people will be born without these parts. Lamarck believed that evolution happens according to a prearranged plan and that the results have already been decided. Charles Darwin ( ) Charles Darwin is famous for the theory of evolution and Natural Selection, or Survival of the Fittest. He dedicated his life to studying plants and animals and believed that the desires of animals have nothing to do with how they evolve. He said that organisms, even of the same species, are different in some ways, and over time those creatures which are adaptable, survive, while those that do not adapt to changing conditions, such as climatic and environmental change, do not live to breed and pass on their genes. He came to the conclusion that there was a variation of physical and behavioral features within a species. Organisms which had features that helped them to adapt to their environment and circumstances had a better chance of survival than individuals who lacked these features. These adaptable organisms survived to breed and produce offspring which generally inherited the successful features of their parents. He called this process natural selection. Darwin knew that organisms evolved and changed from generation to generation, but did not know how traits were passed on from one generation to another. Only after more was understood about genetics, was this explained. Darwin also suggested that each species evolves over time and adapts to the environment in which they live. Thus, the same species living in different environments will evolve differently and become more and more differentiated (different) over time. He believed that all species of life on Earth are interrelated and have a common ancestor. Is natural selection a fact or a theory? Explain your answer. What science was developed later which was found to support Darwin s theory? Which theory sounds like an explanation that Lamarck might give? Explain your answer.

22 Which theory sounds like an explanation that Darwin might give? Explain your answer. What are the specific clues that most clearly distinguish a Darwinian explanation from a Lamarckian explanation? What term did Lamarck use to explain how new species emerged? What term did Darwin use to explain how new species emerged? Do you think there is any similarity in the theories proposed by the two scientists? Explain. Evolutionary biologists studied both Lamarck and Darwin s theories very carefully. Darwin s theory has been supported by a lot of evidence. Lamarck s Theory of Inheritance of Acquired Characteristics has been disproved. Write a paragraph on why we should believe Darwin and disprove Lamarck. Give suitable examples to back your argument. Stop here for today

23 Day 9 How was the Earth made? Video: How the Earth was Made Directions: Complete the first prediction column of the anticipation guide before the movie and the actual answer column at the end of the movie. Predictions Questions Actual Answer (circle one) True/False Scientists believe that Earth is 4.5 billion years old. True/False Pangea is the only theorized supercontinent formation True/False Without the burning of Earth s core, life would not be able to survive. True/False Scientists believe that we are living between 2 ice ages True/False Pangea Ultima is believed to form in 2 million years from now True/False Earth s core will one day cool and share the fate of Mars Introduction Questions: Directions: While watching the video, answer each question for the introduction of the movie. 1. How did scientists discover the age of the Earth? 2. Who is known as the father of modern geology? 3. What was Hutton s conclusion based on his observations? 4. How old did Arch Bishop Usher claim that the Earth was? 5. What year did Hutton find his proof? 6. What was the proof he found? 7. What did Lord Kelvin believe about the Earth? 8. Who discovered Radiometric Dating? Timeline: Directions: Complete the timeline below during the movie. 4.5 Billion Years Ago Earth forms from colliding The surface is a molten ocean Earth is preparing to change into a When is pillow lava formed?

24 4.4 Billion Years Ago Gradual cooling of the is allowing the planet to solidify Water begins to form on the surface Surface rocks begin emitting 4 Billion Years Ago Thick form from large amounts of water off the surface. The water in the atmosphere rained down for millions of years on the Earth causing of the surface to be covered with water. Small volcanic islands appear The seas are rich, giving them a color CO2 covered the skies causing them to appear Temperature exceeded degrees F 3.5 Billion Years Ago Underwater volcanoes gave rise to This granite begins the formation of the Granite is produced by superheated water and basaltic water o Why is granite special? o Why is granite good material for continental plates?

25 2.5 Billion Years Ago Single celled organisms trigger the production of oxygen o What is the name of this organism? o Where can you find these organisms today? Why was the discovery of stromatolites a revolution in the fossil record? 1.5 Billion Years Ago Iron begins to leave the oceans Increased levels make the sky and ocean look blue Earth begins to resemble the planet we know The continents begin to move o What is the science of Plate Tectonics? o What fresh water organism was used to link the theory of plate tectonics? o What year was the Theory of Continent Drift proposed? o Who was the scientist who proposed this theory? o Why did geologists have a hard time believing Wegner? 1 Billion Years Ago The first is formed. It is called This continent is very different because it does not support life. Rodinia triggers SNOWBALL EARTH due to: The land begins to freeze which reflects the sun s light away from the planet o Why is it called SNOWBALL EARTH? 700 Million Years Ago Surface temperatures on Earth are below degrees F Oceans are covered in an ice sheet mile deep Much of the life in the oceans is dying o What is causing the death of these organisms? 25

26 650 Million Years Ago Beneath the ice, were erupting breaking the continent apart The heat from the eruptions creates a temporary effect and melts the snowball. Ice retreats to the poles 500 Million Years Ago Life in the oceans begins to become complex due to the increase in levels. o This is known as the explosion Diamond mines are discovered to be the mouths of very deep volcanoes Movement of the continents caused the super eruptions which bear these diamonds Over the next few 100 million years, life will flourish and large animals called dinosaurs will rule the Earth. 65 Million Years Ago Vegetation is lush Dinosaurs rule the Earth o is found large amounts in the tombstone layer An enormous meteor lands in Mexico. Along with eruptions, the meteor causes a huge cloud of dust which This dust cloud causes of the Earth s life to become extinct. 50 Million Years Ago Life begins to recover begin to flourish Plate tectonics, weathering and erosion create the continents that we know today. o How was the Alpine chain formed o What do the quartz crystals reveal? 6 Million Years Ago How was the Grand Canyon formed? What makes the Colorado River so powerful? 26

27 2 Million Years Ago Ancestors of humans begin to spread out of Africa from the North Pole begin to descend Earth enters the first ice age. o What is believed to have caused the ice ages? How was the Ice Age Theory formed? o What is some evidence that supports this theory? The future What are some of the theories that scientists have about the future of Planet Earth? Day 10 What evidence do we have that supports the theory of evolution? Evidence of Evolution Stop here for today Complete the chart as you move through the interactive. Evidence What it tells us: Past Lives 1. growth rings in fossil trees or shells Growth rings tell us the number of years that individual lived. 2. curled up fossil trilobites 3. the contents of fossil nests 4. fossils of many individuals of the same species together 5. a change in the shape of a feature over time Geologic Time 1. layers in the rocks 2. index fossils 3. fossil shells on mountain tops 4. identical fossils on widely separated continents 27

28 Evidence What it tells us: Paleoecology 1. fossil marine animals in the desert 2. shapes of leaf edges 3. tooth marks in fossil shells 4. fossil pollen Biodiversity 1. fossils of organisms no longer alive today 2. features that are shared by more than one species 3. the extinction of many fossil species at the same time 4. the extinction of one group of organism, like corals, on which other organisms depend Day 11& 12 How do fossils show evolution? Stop here for today Examining the Fossil Record (small group activity; will take 2 days) Objectives: analyze characteristics of fossils compare placement of fossils and determine relative ages develop a model evolutionary tree based on the morphology and age of fossils Background Information: Fossils are traces of organisms that lived in the past. When fossils are found, they are analyzed to determine the age of the fossil. The absolute age of the fossil can be determined though radiometric dating and determining the layer of rock in which the fossil was found. Older layers are found deeper within the earth than newer layers. The age and morphologies (appearances) of fossils can be used to place fossils in sequences that often show patterns of changes that have occurred over time. This relationship can be depicted in an evolutionary tree, also known as a phylogenetic tree. 28

29 There are two major hypotheses on how evolution takes place: gradualism and punctuated equlibrium. Gradualism suggests that organisms evolve through a process of slow and constant change. For instance, an organism that shows a fossil record of gradually increased size in small steps, or an organism that shows a gradual loss of a structure. Punctuated equilibrium suggests that species evolve very rapidly and then stay the same for a large period of time. This rapid change is attributed to a mutation in a few essential genes. The sudden appearance of new structures could be explained by punctuated equilibrium. Speciation The fossil record cannot accurately determine when one species becomes another species. However, two hypotheses regarding speciation also exist. Phyletic speciation suggests that abrupt mutations in a few regulatory genes occur after a species has existed for a long period of time. This mutation results in the entire species shifting to a new species. Phyletic speciation would also relate to the Punctuated Equilibrium hypothesis regarding evolution. Divergent speciation suggests that a gradual accumulation of small genetic changes results in subpopulation of a species that eventually accumulate so many changes that the subpopulations become different species. This hypothesis would coincide with the gradualism model of evolution. Most evolutionary biologists accept that a combination of the two models has affected the evolution of species over time. 29

30 Procedure: 1. The diagram you are creating requires a large space. To create your workspace, tape together 4 sheets of standard sized construction paper. Use a ruler to draw the following chart on your workspace. I have a sample on the board, please refer to it so you are doing it correctly! Time Period ( 1-1/2 inches wide) Began (years ago) ( 1-1/2 inches wide) Fossils (9 inches wide) Wyomington (oldest) 995,000 (Each row here must be 3-1/2 inches tall) Ohioian 745, 000 Nevadian 545,000 Texian 445,000 Oregonian 395,000 Coloradian 320,000 Montanian 170,000 Californian 80,000 Idahoan (the present) 30, The group of "fossils" you will work with are fictitious animals. Each fossil on your sheet is marked with a time period. Cut out each fossil and make sure you include the time period marked below it. 3. Arrange the fossils by age. On your data chart, place each fossil next to the period from which the fossil came from. The term "upper" means more recent and should be placed lower in the row. The term "lower" means an earlier time period, fossils from a "lower" time period should be place toward the older time periods. In each fossil column, you may have 3 specimens, one from the main time period, one from the upper and one from the lower. Not all fossils are represented, illustrating the incompleteness of any fossil record. 30

31 4. While keeping the fossils in the proper age order, arrange them by morphology (appearance). To help you understand the morphology of the specimen, view the diagram. Arrange the fossils using the following steps. a. Center the oldest fossil at the top of the fossil column (toward the oldest layer) b. Through the chart, those fossils that appear to be the same (or close to the same) as the fossils preceding them should be placed in a vertical line c. During a certain period, the fossils will split into two branches. In other words, one fossil from that period will show one type of change, and another fossil will show a different change. When this happens, place the fossils side by side in the appropriate time period. From this point on you will have two lineages? 5. Once all the fossils have been placed correctly according to time and morphology, glue the fossils in place. Give a brief description of the evolutionary changes that occurred in the organism. During which time period did the fossils differentiate into two branches. Examine the fossil that was unearthed in a museum, apparently the labels and other information were lost. Using your fossil record, determine the time period this fossil is likely from. Of the two major species that arose from the parent species, which was more successful? How do you know? For each of the "blanks" on your fossil record make a sketch of what the animal would look like. Draw these right on your fossil record. Stop here for today 31

32 Day 13 What is morphology? What are the different types of structures and how did they evolve over time? Evidence of Evolution: Morphology In our studies of the anatomy and development of animals we have discovered that many living creatures that look quite different on the surface have similarities underneath their skin that suggest that they are related to each other. This is evidence that living creatures have evolved, or gradually changed over time. In this lab, you will learn about homologous, analogous, and vestigial structures and their value as evidence for evolution. INSTRUCTIONS A. HOMOLOGOUS STRUCTURES There are many examples of body structures that are formed in similar ways during embryonic development and that share similar patterns of bone structure, even though they take on different forms and perform somewhat different functions. These structures are called homologous structures. Homo- means same, and logous means information, so homologous means same information. Homologous structures mean that the animals share a relatively recent common ancestor. 1. Carefully examine the drawings of forelimb skeletons shown on your guided notes sheet. Look for similarities in the bones amongst the various animals. 2. Color in the human arm first. Color the bones of the arm: humerus = blue ulna = green radius = red Color the bones of the hand (the carpal, metacarpals, and phalanges) = yellow. 3. Color the corresponding bones in each of the other animals the same color as the human bones. 4. Observe each of the skeletons again, and describe the function of each limb in the Table on your guided notes sheet. 5. Answer Summary Questions for this section (#1-4). 32

33 B. ANALOGOUS STRUCTURES There are also many examples of body structures in animals that are very similar in function and superficially similar in form and but develop very different and have very different internal structures and embryonic development. These structures are called analogous structures. Analogous structures mean that the animals do not share a recent common ancestor. 1. Examine the butterfly wing and the bird wing shown in Figure 2 below. 2. Look for any similar bone structure. 3. Answer Summary Questions for this section (#5-7).. Fig. 2 C. VESTIGIAL STRUCTURES There are also many examples of body structures in animals that show gradual changes over time. In some cases, these changes have reduced or removed the function of some body parts and organs. These reduced or lost structures are called vestigial structures. The wings of penguins and the leg bones of snakes are examples of this phenomenon. 1. Observe the drawings of the cavefish and the minnow shown in Figure 3. The fish are related to each other but the cave fish is blind and only has the remnants of an eye. 2. Answer Summary Questions for this section (#8-9). 33

34 Phalanges Animal Function human whale cat bat bird crocodile HOMOLOGOUS STRUCTURES 1. Are the functions of the limbs of each of the animals illustrated the same or different? 34

35 2. Are the bones of the limbs arranged in a similar or in a very different way in each animal? 3. Does the similarity in bone structure suggest a common ancestry amongst these animals? 4. Offer a possible evolutionary explanation for how the skeletons can be similar but the functions very different in each of the animals. ANALOGOUS STRUCTURES 5. What function do the butterfly and bird wings share? 6. In what way do these structures differ? 7. Explain why these are considered analogous structures and not homologous structures. VESTIGIAL STRUCTURES 8. Explain why eyesight is not an important adaptation to life in a deep sea cave. 9. Does the appearance of the cavefish and the minnow suggest a common ancestry? Why? Stop here for today 35

36 Day 14 What is morphology? Morphology Complete the chart as you read through this information. What is it? Shows common ancestry between... Middle Ear Diaphragm Milk teeth Body Hair Sweat glands Pentadactyl limb Lungs Bilateral symmetry Cells DNA Hominid skulls 36