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VISTA 3 CATACLYSMS AND CATASTROPHES

By Ray Watkins,2014-05-07 11:05
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VISTA 3 CATACLYSMS AND CATASTROPHES

    GEOPHYSICS

Module: Madagascar From the Ground Up

Document Contents:

Overview . . . . . . . . . . 2

Correlation to National and Texas Education Standards . . 2

Did You Know? . . . . . . . . . 3

    Resources . . . . . . . . . . 4 The Earth: Layers upon layers . . . . . 4

    Exercise 1: Exercise 2: Wegner’s Puzzle . . . . . . . 6

    Exercise 3: The Traveling Island: Madagascar . . . . 7

    Exercise 4: Learning from Lemurs: A lesson in island biogeography . . 9

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    VISTA 2: MADAGASCAR FROM THE GROUND UP

VISTA TOPIC

    ? The Earth: Layers upon layers

    ? The Traveling Island: Madagascar and plate tectonics

    ? Learning from Lemurs

VISTA OVERVIEW

    The focus of this module is Madagascar’s geological history. With this vista students will explore the composition of the earth and how the earth changes through time. Additionally, students will investigate how geological change

    can affect global modifications. With the activities presented in this vista, students will discover how global

    changes affect plant and animal diversity and how these changes are traced through time.

    ? Students will explore the composition of the earth understanding that the earth is composed of four distinct

    layers.

    ? Students will become familiar with the processes involved in plate tectonics.

    ? Students will uncover the geological history of Madagascar and how its history has affected the evolution

    and diversification of lemurs.

ABOUT THE VISTA

    Correlation to Fourth Grade Texas Essential Knowledge and Skills (TEK’s):

    TEKS

    Topic 1 2 3 4 5 6 7 8 9 10 11

    Madagascar From A, C, A, A,B A A A,B, A,B

    the Ground Up D, E D,E C

Correlation to National Science Education Standards Grades K- 4:

    Scientific Inquiry Earth and Space Science

    ? Abilities necessary to do scientific inquiry ? Properties of earth materials

     ? Changes in the earth

    Physical Science

    ? Properties of objects and materials History and nature of Science

    ? Position and motion of objects ? Science as a human endeavor

    Life Science Science in Personal and Social Perspectives

    ? Organisms and environments ? Changes in environments

     ? Characteristics and changes in population

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Correlation to Benchmarks for Science Literacy

    BENCHMARK

    VISTA 1 2 3 4 5 6 7 8 9 10 11 12

    Madagascar B,C, A,D A,B, A,B, From the A,B,C A,B C D,E,F E,F C C,D,E Ground Up

    BACKGROUND FOR TEACHERS: DID YOU KNOW?

    Charles Darwin experienced several earthquakes and volcanic eruptions during his natural history

    expeditions in the mid 1800’s. It was during these trips that Darwin recognized that the earth is a dynamic ever-

    changing powerhouse. Neither he nor his contemporaries could appreciate how extensively continents and

    oceans have changed over time, and how profoundly those alterations have affected the distribution and

    evolution of biological species. Our globe has been in flux for more than four billion years. Continents merge,

    fragment, and sometime collide with each other. Such movements impact ocean currents, atmospheric

    circulations, and continental temperature and rainfall patterns. This vista focuses on Madagascar, the fourth

    largest island in the world. To take a trip to Madagascar is like traveling back in time to the Eocene. Until

    relatively recently (~1500 years before present) this island remain untouched by humans, and as a result, it has

    extreme biological diversity in both its plant and animal life and has high levels of endemism. The lemurs of

    Madagascar are endemic the island. Endemic means that an animal has evolved in isolation and cannot be found anywhere else in the world. Discussed below is how advancements in geological science have helped

    biologists and anthropologists understand the evolution of primates on the island of Madagascar.

    In 1915 a German meteorologist Alfred Wegener suspected that the continents might have once formed a single giant landmass. The remarkable jigsaw fit of the continental margins (South America and

    Africa in particular) led Wegener to this conclusion. Originally most geologists dismissed Wegener’s ideas

    because a mechanism for continental movement was not known. By the 1950’s evidence gathered by oceanographers began to build which supported Wegner’s original conjecture. Oceanographers revealed the

    rocks in the mid-ocean ridges were of relatively recent origin. New crust is formed by hot lava from deep

    within the earth pushing up through faults and spreading out to form the sea floor. The Canadian geophysicist

    Tuzo Wilson deduced that the earth’s crust is divided into a series of plates. The continents of lighter rock float

    on the heavier plates of solidified magma; their movements are known as plate tectonics.

    The theory of plate tectonics is to geophysics as natural selection is to biology/anthropology. About

    200 million years ago all continental landmasses were closely packed. India was close to Africa and

    Madagascar was wedged between them. This giant landmass is called Pangaea (meaning all lands). Plants and

    animals on Pangaea were a continuous living system and quiet homogenous in structure. Through time Pangaea

    slowly separated, Madagascar and India “drifted” away from Africa. Millions of years later, India drifted north

    colliding with mainland Asia, raising the Himalayan mountains leaving Madagascar in its current location

    (~200 miles off the coast of south east Africa). As the continental plates “drift” away from one another, the continuous and homogenous landscaped changed since global placement of the continent effect climate and as a

    results plant and animal life are modified. Continental drift answers question that previously baffled zoologist,

    botanists, and paleontologist. Dinosaur fossils, for example, are found on all major landmasses. One question

    that has stumped scientists for hundreds of years was how particular dinosaur species found themselves on

    isolated landmasses. How did they cross the oceans? The answer is that these animals did not have to cross the

    ocean. Dinosaurs evolved during the Triassic on Pangaea and today their fossil can be found on all major

    landmasses around the world.

    Primates evolved approximately 80-65 million years ago. The first true primates are divided into two

    groups know as the Adapids and the Omomyids. Most anthropologists think that Adapids evolved into modern lemurs, while Omomyids evolved into modern day monkeys, apes, and humans. Anthropologists think that the

    first lemurs may have reached Madagascar during the Eocene (~70 million years ago). Several hypotheses have

    been presented to explain how lemurs arrived on the island of Madagascar. During the Eocene the placement of

    the continental landmasses were roughly similar to their current placement. Since the first primates evolved

    after Madagascar separated from Africa, scientists have concluded that these animals must have arrived on the

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island by rafting on vegetation across the Mozambique Canal (the waterway between Africa and Madagascar)

    rather than being indigenous to the island and drifting with the island. One of the great lemur mysteries is

    exactly how and why lemurs arrived on the island Madagascar.

    The activities presented here will give students a basic understanding of the earth’s anatomy and the

    mechanisms that cause global change. As the earth is modified geologically, changes occur to the biological

    world. Since the mystery of lemur origins on Madagascar remains a mystery, students will be able to explore

    these questions creatively. Ultimately, based on the evidence gathered from these activities, students will

    uncover some possible explanations as to how and why lemurs arrived on the island of Madagascar.

RESOURCES

Web Sites

    1. Earth layers

     http://volcano.und.nodak.edu/vwdocs/vwlessons/lessons/lesson.html

     http://www.thetech.org/exhibits/online/quakes/inside/core.html

     http://pubs.usgs.gov/publications/text/inside.html

     http://www.usoe.k12.ut.us/curr/science/sciber00/7th/earth/sciber/erlayers.htm

2. Plate tectonics

     http://www.ucmp.berkeley.edu/geology/tectonics.html

     http://pubs.usgs.gov/publications/text/dynamic.html

     http://www.platetectonics.com/

     http://www.cotf.edu/ete/modules/msese/earthsysflr/plates1.html

     http://www.brainpop.com/science/seeall.weml

     http://www.beyonddiscovery.org/content/view.article.asp?a=229

3. Primate evolution

    http://www.leeds.ac.uk/chb/lectures/anthl_09.html

    http://anthro.palomar.edu/earlyprimates/first_primates.htm

LEARNING EXPERIENCES

Learning Experience 1: The Earth: Layers upon layers

    With this activity students will set a foundation for other activities presented in this vista. The earth’s internal

    structure influences plate tectonics. In order for students to comprehend plate tectonics, students first need to

    understand that the earth is made up of several layers each unique from the other.

Background

    The earth is similar to a giant everlasting gobstopper. Like the gobstopper the earth is made up of

    layers, but unlike the gobstopper, it is impossible to reach the center of the earth. For approximately 100 years

    geologists have known that the earth is composed of four layers: the crust, mantle, outer core, and inner core.

    In 1909, a geologist by the name of Andrija Mohorovicic discovered that earthquake waves near the surface of the earth move slower than earthquake waves that pass through the interior of the earth. Primary school students

    may have difficulty understanding wave properties. To illustrate wave properties show the class what happens

    to still water when it is struck by a rock (splash, rock sinks, ripple effect). Andrija Mohorovicic noticed the

    seismic waves (P waves) did not pass through the earth in a straight line. The seismic waves were being

    deflected or bent by some dense internal structure of the earth. Andrija Mohorovicic decided outermost layer of

    the earth, the crust, was made of less dense material than the second layer of the earth, the mantle.

    The crust is the outermost layer of the earth and is divided into two types: oceanic crust and

    continental crust. The crust is relatively thin compared to the earths others layers. Oceanic crust averages 7 km

    in thickness (~3miles), while continental crust averages between 30-50km (thickness does not include

    mountains). The temperature of the crust at the surface is 0 degrees Celsius at its surface and 870 degrees in it

    deepest parts. The crust is composed of granite, basalt, quartz, calcium, magnesium, carbon dioxide, clay and

    iron. The mantle is the largest layer of the earth. It is compose of very hot dense rock that flows like asphalt.

    The mantle is 2885 km (1800 miles) thick. Its temperature ranges from 500-2000 degrees Celsius. The mantle

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is composed of Aluminum, melted rock, iron, magnesium and calcium. The outer cores lies beneath the mantle

    and can reach temperatures up to 5000 degrees Celsius. Due to high temperatures all its components are all in a liquid state. The thickness of the inner core is 2270 kilometers (1400 miles). The outer core is composed of melted iron, melted nickel, and sulfur. The inner core is locate in the center of the earth and is approximately

    800 miles thick and composed of solid iron and nickel. The temperatures at the core of the earth can reach 7000-9000 degrees Celsius.

     One concept that students need to understand is density and how it related to how the earths layers are formed. The inner core is solid iron and nickel. These elements are denser than materials found in the mantle and the crust. If the crust was denser than the mantle, the crust would sink below the mantle. To illustrate this point, you may want to use household items such as oil and water. These two substances differ in density. Oil is less dense than water, therefore when water and oil are mixed, oil rises above water.

Time Frame

    1 hours (does not include preparation time)

Materials

    ? 1 lime

    ? 4oz package of instant vanilla pudding

    ? 8oz package of black cherry gelatin dessert

    ? 4 cups of boiling or boiled water

    ? 4 cups of cold water

    ? 3 mixing bowls

    o One ten inch bowl to make the earth

    o 2 bowls to set vanilla pudding and black cherry gelatin ? 12 graham crackers

    ? ? cup of melted margarine

    ? ? cup of granulated sugar

    ? Colored chalk

    ? Earth layers hand out (gk12-geophysics-ex1)

Advanced Preparation

    ? Prepare instant vanilla pudding and black and refrigerate for approximately 2 hours.

    ? Download and print the earth layers hand out so each student will have one.

    ? Review materials presented in background.

Procedure

    1. Inform the class of the activity.

    2. Ask the students to inform you about what they know about the earth’s composition.

    3. Walk the students through the information presented in the background section. 4. Use the colored chalk to draw the earth’s layers.

    5. Allow students to discuss the composition of each layers.

    6. Once students have investigated all the earths layers, begin the hands on activity. 7. Begin with the earths crust. Have the children crush the gram crackers into fine crumbs. 8. Mix the gram crackers with the melted margarine and granulated sugar. 9. Press the gram cracker mixture on the bottom and along the sides of the 10 inch bowl. 10. While completing the task, review the composition and structure of the crust. 11. Remove the gelatin form the refrigerator.

    12. Construct the mantle by spooning the black cherry gelatin into the bowl on top of the gram cracker mixture.

    Make sure to leave approximately 5-inch pocket in the center.

    13. While constructing the black cherry gelatin mantle, discuss its temperature, texture, and size of the actual

    mantle.

    14. Construct the outer core. Spoon in the lemon gelatin, leaving a two inch hole in the middle 15. While constructing the outer core, discuss its composition.

    16. Construct the inner core. Cut the lime in half. Place it in the center of the edible earth.

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17. Discuss all four layers. It is import for students to understand that the crust is the thinnest part of the earth,

    while the mantle represents the largest component of the earth. Additionally, although edible earth is cold,

    it is extremely important for students to understand the inner layers of the earth are extremely hot.

Formative Assessment

    1. How did Andrija Mohorovicic discover that the earth’s crust was made of less dense rock than the mantle?

    2. Name the four layers of the earth in order from the center of the earth to the outside.

    3. What are the two main metals that make up the outer and inner core?

    4. As the students to describe the consistency of the mantle.

    5. Ask the students to describe in their own worlds what the earth’s layer were formed.

    Learning Experience 2: Wegner’s Puzzle This activity will introduce students to the theory of plate tectonics and the supporting evidence. Students will

    explore the mechanism of plate tectonics in the third learning experience. The world is approximately 4 billion

    years old. We know today that the world is constantly changing and that global modification affects ever

    biological organism on the plant, therefore it is of utmost importance for us to understand how these

    modification transpire and at what rate these changes occur. By understanding plate tectonics students will

    understand why there are mountains in some areas, why volcanoes and earthquakes occur in some areas and not

    others, why there are similar rocks on continents separated by oceans, and why some animals are similar and

    some different.

Background

     The same natural processes produce all earthquakes, volcanoes, and mountains. We know this to be

    true today, but even as little as one hundred years ago scientists were unsure as to how these geological

    processes occurred. Before scientists explored these processes using the scientific method, most people used

    folklore and legend to explain these processes. For example, the ancient Japanese legend of Namazu explained

    why earthquakes occur. Namazu was a giant catfish that lived under the surface of the earth. It would shake

    violently and cause great destruction from time to time. Kashima, who is a Japanese god, was the only god that

    was strong enough to control Namazu. Kashima would hold Namazu down and pin the catfish under a rock.

    When Kashima’s mind would wonder, Namazu would escape and cause another earthquake.

     Many cultures have tried to explain why earthquakes and volcanoes occur through stories about their

    gods and goddesses. The Hawaiian Islanders thought that volcanoes were the home of the fire goddess Pele.

    The Romans believed that the blacksmith god, Vulcan, used volcanoes as his forge to produce weapons.

     For hundreds of years people throughout the world explained earthquakes and volcanoes through myth

    and legend. In 1620 an Englishman name Sir Francis Bacon declared that it was not gods and goddesses that

    caused natural disasters. He noticed that the coast of Africa and South America were very much alike. In fact

    they could almost fit together like pieces of a jigsaw puzzle. Why are there similarities between the coasts of

    Africa and South America? As humans continued to travel the world they observed seashells high in mountains

    many miles from the nearest ocean. Many wondered how those seashells ended up on top of mountains. These

    observations and questions led scientists to believe that the earth is a dynamic plant. However, it was not until

    the 1960’s that scientists started to agree that the continents could move across the surface of the earth.

     In 1915 the German meteorologist Alfred Wegener showed that rock bands in South America and

    Africa matched in mineral content and age. Wegner concluded that the continents must have drifted apart

    hundreds of miles. However, he did not supply an explanation as to how these massive continents could move,

    therefore his idea was dismissed by the scientific community. It was not until the 1960’s that geologists gained

    the technology to fully understand the processes that could move the earth’s continents. Geologists concluded

    that that the earth’s surface was composed of not one large sheet but more that 12 major pieces of crust.

    Geologists call these pieces plates. These plates float across the surface of the earth like an iceberg floats on the

    ocean.

     To see the major plate bounders please visit www.ig.utexas.edu/research/projects/plates/images/topo.pb.htm. The

    lines on the map indicate the position of the plate boundaries. Boundaries are places where the plates meet.

    Now geologists can finally explain the reason that mountains are built, volcanoes erupt, and earthquakes occur.

    The plate tectonics theory of continental movement can explain scientifically why all of these geological

    processes can occur. Human no longer have to try to explain these natural occurrences through myth and

    legend.

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Time Frame

    1.5 hours

Materials

    ? Two maps: The world today and Pangaea (gk12-geophysics-ex2) ? Two World Cut Up Maps (gk12-geophysics-ex2)

    ? Two pieces of blue construction paper (9X12)

    ? Glue

    ? Scissors

    ? Markers

Advanced Preparation

    ? Download, resize, and print images for students. Students can work in groups or independently.

    ? Download answer image of what the world will look like 100 million years from now

    (http://www.ig.utexas.edu/research/projects/plates/100_future.htm)

    ? Review materials

Procedure

    1. The students will study the “World Today Map.” The black arrows indicate the direction of plate

    movement) and the “Pangaea” map. 2. Instruct the students to cut the two “World Cut Up” maps on the red lines.

    3. The students will then place and paste the continents at the position that they were located 250 million

    years ago in the great ocean called Panthassia.

    4. The students will then make a predation of what the world will look like in 100 million years. The students

    should use the “World Map Today” in making their predictions.

    5. Instruct the students to place the remaining continent cutouts and paste them onto the other piece of blue

    construction paper.

    6. The students should also predict where new mountains will form and where new volcanoes will erupt by

    marking them on their prediction maps using markers.

    7. Have student write in their notebooks what their reasons were for placing the continents where they did.

Formative Assessment

    1. How did historical Japanese peoples explain earthquakes?

    2. How do scientists explain earthquakes?

    3. How did Alfred Wegner try to prove that the continents of Africa and South America were once connected?

    4. Ask the students to explain the continental drift theory in their own words and supply evidence to support

    their statement.

Learning Experience 3: The Traveling Island: Madagascar

    The primary objective of this learning experience is not only to review but to illustrate the mechanism behind

    plate movement though time. This learning exercise will introduce students to the concept of convection

    currents. Convection currents within the mantle move the 12 large plates around the globe. Convection currents

    are a difficult concept of many young students to understand without observation. This learning exercise was

    adapted from an activity created by the Lawrence Hall of Science (A current Event, GEM Series, University of

    California, 1988).

Background

    The earth is made up of layers: The crust, mantle, outer core, and inner core. In addition to these basic layers

    geologists have distinguished two more layers that act as an important interface between layers. These layers

    are called the lithosphere and asthanosphere. The lithosphere is made of the crust and the rigid outer zone of

    the mantle. The lithosphere is broken into 12 large pieces that are called plates. The zones directly under the

    lithosphere are made of a flowing, denser layer called the athenosphere. Scientists think the 12 large plates ride

    on the athenosphere. Exactly what drive plate tectonics is not known. One theory is that convection within the

    earth’s mantle pushes the plates. Therefore, movement of the plates is attributed to convection currents.

    Convection currents are very slow vertical circulation movements that are regulated by differences in

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    temperature and density within the mantle. Essentially, the processes by which heat moves deep in the interior of the earth is investigated by computer simulations which can be compared with seismic and heat flow data that show temperature variations in the earth’s interior. Both measurements and simulations show that the hottest part of the earth’s interior is the iron core. As a result, the core heats the bottom of the rocky mantle.

    This begins a cycle in which the very hot material at the deepest part of the mantle rises, then cools, and sinks again, and then heats, rises, and repeats the cycle over and over. Geologists think that the movement of heat by convection currents at the upper layer of the mantle causes the molten rock of the mantle to move slowly in huge streams. Therefore, the flow of the convection currents in the mantle is responsible for the drifting of the earth’s tectonic plates.

     Plate tectonic activity takes place at four types of boundaries: divergent boundaries (where new crust is formed = see floor spreading), convergent boundaries (where crust is consumed = subduction), collisional boundaries (where two land masses collide = mountains), and transform boundaries (where two plates slide against each other = earthquakes).

     Diagram of demonstration 1: Explanation- The central heat source causes the warmed water to rise in the center. Warm water is lighter, less dense than cold water. The warmed water molecules are excited and move faster. After they rise, they move along the surface to the edge where they cool, become denser and sink to the bottom. Being on the bottom they become part of the source being heated and are drawn towards the center. The can be sketched in a doughnut type pattern.

    Time Frame

    1.5 hours

Materials

    ? Colored chalk

    ? Moving plates PowerPoint (gk12_geophysics_lecturesupp1.ppt)

    ? Madagascar moving plates PowerPoint (gk12_geophysics_lecturesupp2. ppt)

    ? Projector

    ? Projector screen

    ? Computer Demonstration 1

    ? Water (boiled water and ice cubes)

    ? Red and blue food color

    ? Clear tray (8 inches or greater)

    ? Eye dropper

    ? 4 styrofoam cups

    Demonstration 2

    ? Hot plate

    ? Clear saucepan

    ? Wire whisk

    ? Small cups

    ? Hot chocolate ingredients

    ? 1 cup water ? 2 squares unsweetened baking chocolate ? 1/2 cup sugar ? 3 cups milk (thick) ? 1 tsp. vanilla

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? Shredded coconut

Advanced Preparation

    ? Gather materials and set-up demonstration table.

    ? Download plate’s files and set up projector to present the moving plates PowerPoint.

Procedure

    1. Review the earths layers with students: The crust, mantle, outer core, and inner core. 2. Introduce students to the new layers: the lithosphere and the asthanosphere.

    3. Review the evidence for the giant super-continent: Continents fit like puzzle, similar rock types on distant

    continents, and similar fossil forms on distant continents.

    4. Present the plates PowerPoint to students.

    5. Describe the following experiments (demonstrations) to the students.

    6. Make a large drawing on the board of the convection current experiment (image provided in the

    background section).

    7. Ask students to draw prediction of what will happen.

    8. For the first demonstrations: Fill clear tray with ice cold water. Place tray on top of three evenly spaced

    and inverted Styrofoam cups.

    9. Fill the forth cup with HOT water and slide under the center of the tray.

    10. Using the eyedropper, gently place the blob of food color inside the tray on the bottom directly over the

    heat source.

    11. Add the second color to the bottom outside edge of the tray away from the heat source. 12. Allow students to observe what occurs for about 5 minutes.

    13. Have the students make a second drawing of what actually occurred (results).

    14. Review the earth’s layers and their composition.

    15. Allow students to discuss how convection currents may move the earths plates. 16. As students discuss the above question, prepare for demonstration two.

    17. Heat water and chocolate in heavy 2-quart saucepan on low heat, stirring constantly with wire whisk until

    chocolate is melted and mixture is blended.

    18. Add sugar; increase heat to medium-high. Bring to boil. Boil 3 minutes, whisking constantly. Gradually

    whisk in milk and vanilla.

    19. Allow mixture to settle. Add 2-3 tablespoons of shredded coconut in the center of the saucepan. 20. Inform the students that the shredded coconut models the earths crust and the chocolate milk the earth’s

    mantle. The hot plate represents the inner and outer core.

    21. Allow the mixture to boil. Allow students to observe how the boiling hot chocolate moves the coconut

    shreds.

    22. After all students have observed the movement of the coconut sheds, allow students to drink the earth’s

    mantle and crust. Allow students to discuss what they observed.

    23. Guide the student discussion with the questions provided in the formative assessment.

Formative Assessment

    1. Which way does the warmed water move?

    2. What happens when it reaches the surface?

    3. Which way does the cooler water on the edge move?

    4. Is the warmer water heavier or lighter than cooler water? More or less dense? Are the water molecules

    moving faster or slower in warmer water?

    5. Ask students to describe in their own words how convection currents work.

    6. Are convections currents a possible explanation for the plate movement?

Learning Experience 4: Learning from Lemurs: A lesson in island biogeography.

    This learning experience will draw from information used in the Apples and Oranges vista which will help

    students understand how the earth, time, and environment closely tied. With this learning activity students well

    explore questions regarding lemur origins. Students will be introduced how habitats vary geographically and

    how environment to some degree shapes animal form. For example, tree living primates that subsist on fruits

    are not expected to survive or live in dry dessert environment. In this learning experience student will draw

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    from information collected in learning experience one, two, and three to creatively propose an explanation as to why lemurs are found on Madagascar and how these endemic animals arrived on the island.

    Background

     In the first vista, students explored the primate order. Students discovered that primates have a suite of

    traits that make them unique from all other mammalian groups. These traits are grasping hands, nails instead of claws, large brains compared to body size, forward facing eyes, and a greater reliance on vision than on smell. Students also investigated how these traits vary among the primate order and how these traits inform you about how an animal views and exploits its environment. In the adopt-a-primate exercise (Module 1, Exercise 2) students determined that living primates are tropically adapted and found in warm climates. The tropics are defined as the area between the Tropic of Cancer (~30ºN) and Capricorn (~30ºS). This region is where all tropic forest and most non-human primates are found. Based on the current position of continents across the globe, it is extremely unlikely to find a non-human primate outside of Mexico, South/Central America, Africa, and South East Asia.

     Two hundred million years ago, the world looked very different. The major landmasses were connected and the habitats across this super-continent (Pangaea) were homogenous. During this time period Dinosaurs ruled the planet and mammals were non-existent. Approximately seventy million years ago a major global disaster occurred that caused a global mass extinction of the large land-living fauna. Once the Dinosaurs and their preferred ecological settings disappeared, the first mammals proliferated. Alongside mammals like primates, marsupials, tree shrews, and bats appeared the angiosperm rainforests. Angiosperms are plants the produce fruits. It has long been suggested that there is a co-dependence between all primates (including humans) and the rainforests of the world because the majority of primate eat fruit and prefer topical habitats. The first primates are called euprimates. The euprimates are divided into two major groups: the adapids and the omomyids. The adapids are the ancestors of the living lemurs and African and Asian prosimians. The omomyids on the other hand later evolved into modern monkeys, apes, and humans. Like lemurs, the adapids have less specialized sense. Although all adapids have large brains, grasping hands, forward facing eyes, and a reduced reliance on smell, the omomyids had larger brains, specialized grasping ability, and relied more on their eyesight than on smell. Additionally, it has been suggested that these animals may have had color vision like living monkeys, apes, and humans. As the euprimates were evolving they co-existed alongside one another; however as time passed, this changed. Since omomyids had specialized vision and grasping abilities, some scientists think that these animals may have out competed adapids for food resources (fruits) becoming the dominant primate species on Africa and Asia. Approximately sixty million years ago the first adapids may have reached Madagascar. No one knows why or how these animals may have reached the island. Since Madagascar was an island sixty million years ago, students can deduce that these Lemurs did not drift to Madagascar with the island. Today scientists think that lemurs may have rafted to the island on a vegetative raft. Adapids may have reach Madagascar on a vegetative raft, but it doesn’t explain why Lemurs survived and proliferated on

    Madagascar. Students will explore this question based on the evidence provided. One possible explanation is that a small group of fruit eating adapids rafted across the Mozambique Canal reaching Madagascar. The forests of Madagascar were similar to those found in Africa and Asia; however, the Malagasy forests lacked omomyids and other fruit competitors. The empty forests allowed the adapids to evolve into lemurs. The adapids that remained and survived in the forests of African and Asia needed to adapt to their harsh and competitive environments. Rather than competing with the omomyids over fruit resources, the African and Asian adapids became night living and insect eating.

Time Frame

    1 hour

Materials

    ? Environment PowerPoint (gk12_geophysics_lecturesupp3.ppt)

    ? Learning from lemurs interactive PowerPoint (gk12_geophysics_lecturesupp4.ppt)

    10

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