warm up january 10, 2012 1. what is the carbon cycle? 2. what are the 4 main branches of earth...

Warm up January 10, 2012

• 1. What is the Carbon Cycle?

• 2. What are the 4 main branches of Earth Science?

• 3. What are the 4 spheres?

• 4. What does a topographic map show us?

Chapter

11Introduction to Earth Science

Overview of Earth Science

1.1 What Is Earth Science?

Encompasses all sciences that seek to understand

• Earth

• Earth's neighbors in space

Overview of Earth Science

Earth science includes

4. astronomy, the study of the universe

3. meteorology, the study of the atmosphere and the processes that produce weather

1. geology, the study of Earth

2. oceanography, the study of the ocean

1.1 What Is Earth Science?

Earth's Major Spheres

1.2 A View of Earth

1. Hydrosphere• Ocean is the most prominent feature of the hydrosphere.

- Is nearly 71% of Earth's surface

- Holds about 97% of Earth's water

• Also includes fresh water found in streams, lakes, and glaciers, as well as that found underground


1.2 A View of Earth

2. Atmosphere • Thin, tenuous blanket of air

• One half lies below 5.6 kilometers (3.5 miles)

3. Biosphere • Includes all life

• Concentrated near the surface in a zone that extends from the ocean floor upward for several kilometers into the atmosphere


1.2 A View of Earth

4. Geosphere • Based on compositional differences, it consists of the crust,

mantle, and core.

- Crust—the thin, rocky outer layer of Earth.

- Mantle—the 2890-kilometer-thick layer of Earth located below the crust.

- Core—the innermost layer of Earth, located beneath the mantle.

Earth’s Layered Structure

Determining Location

1.3 Representing Earth’s Surface

Latitude and longitude are lines on the globe that are used to determine location.• Latitude is distance north or south of the equator, measured in

degrees.

• Longitude is distance east or west of the prime meridian, measured in degrees.

Satellites and Information Technology

• Key idea: Today’s technology gives us the ability to more precisely analyze Earth’s physical properties

• Remote sensing: collecting data about the Earth from a distance. – Weather—watch temp of air and sea, clouds, storms– Navigation—assist ships and subs exact location– Landsat—photos of land and seacoasts– VLBI—used to measure the earth

• GPS: find precise locations on earth– Military– Geologists– Farmers– Drivers– Sports enthusiasts

What Is a System?

1.4 Earth System Science

Closed systems are self contained (e.g., an automobile cooling system).

Open systems allow both energy and matter to flow in and out of the system (e.g., a river system).

A system is any size group of interacting parts that form a complex whole.

Earth as a System


Earth is a dynamic body with many separate but highly interacting parts or spheres.

Earth system science studies Earth as a system that is composed of numerous parts, or subsystems.

Earth as a System


Sources of Energy• Sun—drives external processes such as weather, ocean

circulation and erosional processes

• Earth’s interior—drives internal processes including volcanoes, earthquakes and mountain building

Earth as a System


Humans are part of the Earth system.

Consists of a nearly endless array of subsystems (e.g., hydrologic cycle)

The carbon cycle

Warm up January 11, 2012

• What is an igneous rock?

• What is a Sedimentary rock?

• What is a Metamorphic rock?

Chapter

33 Rocks

Rocks

3.1 The Rock Cycle

Rocks are any solid mass of mineral or mineral-like matter occurring naturally as part of our planet.

Types of Rocks 1. Igneous rock is formed by the crystallization of molten

magma.

Rocks

3.1 The Rock Cycle

Types of Rocks2. Sedimentary rock is formed from the weathered products of

preexisting rocks that have been transported, deposited, compacted, and cemented.

3. Metamorphic rock is formed by the alteration of pre-existing rock deep within Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids.

The Rock Cycle

3.1 The Rock Cycle

Shows the interrelationships among the three

rock types (igneous, sedimentary, and metamorphic)

Magma is molten material that forms deep beneath the Earth’s surface.

Lava is magma that reaches the surface. Weathering is a process in which rocks are

broken down by water, air, and living things. Sediment is weathered pieces of Earth

elements.

The Rock Cycle

Energy That Drives the Rock Cycle

3.1 The Rock Cycle

Processes driven by heat from the Earth’s interior are responsible for forming both igneous rock and metamorphic rock.

External processes produce sedimentary rocks.

Weathering and the movement of weathered materials are external processes powered by energy from the sun.

Formation of Igneous Rocks

3.2 Igneous Rocks

1. Intrusive igneous rocks are formed when magma hardens beneath Earth’s surface.

2. Extrusive igneous rocks are formed when lava hardens.

Classification of Igneous Rocks

3.2 Igneous Rocks

1. Texture

Igneous rocks can be classified based on their composition and texture.

• Coarse-grained texture is caused by slow cooling resulting in larger crystals.

• Fine-grained texture is caused by rapid cooling resulting in smaller, interconnected mineral grains.

Course-Grained Igneous Texture

Fine-Grained Igneous Texture


3.2 Igneous Rocks

1. Texture (continued)• Glassy texture is caused by very rapid cooling.

• Porphyritic texture is caused by different rates of cooling resulting in varied sized minerals.

2. Composition• Granitic composition rocks are made mostly

of light-colored quartz and feldspar.

Obsidian Exhibits a Glassy Texture.

Porphyritic Igneous Texture


3.2 Igneous Rocks

2. Composition (continued)• Basaltic composition rocks are made mostly of dark-colored

silicate minerals and plagioclase feldspar.

• Andesitic composition rocks are between granitic light-color minerals and basaltic composition dark-colored minerals.

• Ultramafic composition rocks are made mostly from iron and magnesium-rich minerals.

Basalt

Formation of Sedimentary Rocks

3.3 Sedimentary Rocks

• Erosion involves the weathering and the removal of rock.

• Deposition occurs when an agent of erosion—water, wind, ice, or gravity—loses energy and drops sediments.

Weathering, Erosion, and Deposition

Formation of Sedimentary Rocks


• Compaction is a process that squeezes, or compacts, sediments.

• Cementation takes place when dissolved minerals are deposited in the tiny spaces among the sediments.

Compaction and Cementation

Classification of Sedimentary Rocks


1. Clastic sedimentary rocks are composed of weathered bits of rocks and minerals.

• Classified by particle size

Two Main Groups

- Shale (most abundant)

• Common rocks include

- Conglomerate

- Sandstone

Shale with Plant Fossils

Conglomerate



Two Main Groups2. Chemical sedimentary rocks form when dissolved

substances precipitate, or separate, from water.

• Common rocks include

- limestone—most abundant chemical rock

- microcrystalline quartz known as chert, flint, jasper, or agate

- evaporites such as rock salt or gypsum - coal

Fossiliferous Limestone

Features of Some Sedimentary Rocks


Features of sedimentary rocks are clues to how and where the rocks are formed

Warm up 3-31-11

• What is the difference between intrusive igneous and extrusive igneous rock?

• How does the differences on where rock form effect the type of texture it has?

• Explain both compaction and cementation:

Warm Up 4-4-2011

• What is the difference between compaction and cementation?

• Define Intrusive and Extrusive igneous rock:

• Explain texture differences between the two types of rocks:

Warm Up April 4th 2011

• What are 2 types of Sedimentary Rock?

• What are the Two Agents of Metamorphism for Rock

Formation of Metamorphic Rocks

3.4 Metamorphic Rocks

Metamorphism means “to change form.”

Conditions for formation are found a few kilometers below the Earth’s surface and extend into the upper mantle.

Most metamorphic changes occur at elevated temperatures and pressures.



Contact metamorphism occurs when magma moves into rock.

• Changes are driven by a rise in temperature.

• Occurs near a body of magma



Regional metamorphism results in large-scale deformation and high-grade metamorphism. • Directed pressures and high temperatures occur during

mountain building.

• Produces the most metamorphic rock

Agents of Metamorphism


Heat

Pressure

• Provides the energy needed to drive chemical reactions

• Causes a more compact rock with greater density

Origin of Pressure in Metamorphism

Agents of Metamorphism


• Hot water-based solutions escaping from the mass of magma

• Promote recrystallization by dissolving original minerals and then depositing new ones

Hydrothermal Solutions

Classification of Metamorphic Rocks


1. Foliated Metamorphic Rock

2. Nonfoliated Metamorphic Rock

Two main categories

• Has a banded or layered appearance

• Does not have a banded texture

Classification of Metamorphic Rocks

Gneiss Typically Displays a Banded Appearance

Marble—A Nonfoliated Metamorphic Rock

Warm up April 5th 2011

• What is Continental Drift?

• What are 3 types of plate boundaries?

• What is some evidence that proves Continental Drift occurred?

Chapter

99 Plate Tectonics

An Idea Before Its Time

9.1 Continental Drift

Wegener’s continental drift hypothesis stated that the continents had once been joined to form a single supercontinent.

• Wegener proposed that the supercontinent, Pangaea, began to break apart 200 million years ago and form the present landmasses.

Breakup of Pangaea

An Idea Before Its Time


Evidence1. The Continental Puzzle. The coastlines of continents match.2. The mountain ranges match.

3. Matching Fossils- Fossil evidence for continental drift includes several fossil

organisms found on different landmasses.

More evidence

Glaciers were located on parts of continents that are now in or near the tropics (they must have moved)

South America, India, Africa, Austalia (see map)

Matching Mountain Ranges

Rejecting the Hypothesis


A New Theory Emerges• Wegener could not provide an explanation of exactly what made

the continents move.

New technology lead to findings which then lead to a new theory called plate tectonics.

Earth’s Major Roles

9.2 Plate Tectonics

According to the plate tectonics theory, the uppermost mantle, along with the overlying crust, behaves as a strong, rigid layer. This layer is known as the lithosphere.• A plate is one of numerous rigid sections of the lithosphere that

move as a unit over the material of the asthenosphere.

Types of Plate Boundaries

9.2 Plate Tectonics

Divergent boundaries (also called spreading centers) are the place where two plates move apart.

Convergent boundaries form where two plates move together.

Transform fault boundaries are margins where two plates grind past each other without the production or destruction of the lithosphere.

Three Types of Plate Boundaries

Warm Up April 6th

• What is a Transform Fault?

• Describe what happens at a Convergent Boundary. (Continental/Continental)

• What two spheres break up the Geo Sphere?

• Describe a Divergent Boundary?

Divergent Boundaries

9.3 Actions at Plate Boundaries

Oceanic Ridges and Seafloor Spreading• Oceanic ridges are continuous elevated zones on the floor of all

major ocean basins. The rifts at the crest of ridges represent divergent plate boundaries.

• Rift valleys are deep faulted structures found along the axes of divergent plate boundaries. They can develop on the seafloor or on land.

• Seafloor spreading produces new oceanic lithosphere.

Spreading Center

Divergent Boundaries


Continental Rifts• When spreading centers develop within a continent, the landmass

may split into two or more smaller segments, forming a rift.

East African Rift Valley

Convergent Boundaries


A subduction zone occurs when one oceanic plate is forced down into the mantle beneath a second plate.

• Denser oceanic slab sinks into the asthenosphere. Oceanic-Continental

• Pockets of magma develop and rise.

• Continental volcanic arcs form in part by volcanic activity caused by the subduction of oceanic lithosphere beneath a continent.

• Examples include the Andes, Cascades, and the Sierra Nevadas.

Oceanic-Continental Convergent Boundary



• Two oceanic slabs converge and one descends beneath the other.

Oceanic-Oceanic

• This kind of boundary often forms volcanoes on the ocean floor.

• Volcanic island arcs form as volcanoes emerge from the sea.

• Examples include the Aleutian, Mariana, and Tonga islands.

Volcanic island arc—Aleutian islands

Oceanic-Oceanic Convergent Boundary



• When subducting plates contain continental material, two continents collide.

Continental-Continental

• This kind of boundary can produce new mountain ranges, such as the Himalayas.

Continental-Continental Convergent Boundary

Collision of India and Asia

Transform Fault Boundaries


At a transform fault boundary, plates grind past each other without destroying the lithosphere.

Transform faults • Most join two segments of a mid-ocean ridge.

• At the time of formation, they roughly parallel the direction of plate movement.

• They aid the movement of oceanic crustal material.

Transform Fault Boundary

Evidence for Plate Tectonics

9.4 Testing Plate Tectonics

Paleomagnetism is the natural remnant magnetism in rock bodies; this permanent magnetization acquired by rock can be used to determine the location of the magnetic poles at the time the rock became magnetized.• Normal polarity—when rocks show the same magnetism as the

present magnetism field

• Reverse polarity—when rocks show the opposite magnetism as the present magnetism field

Paleomagnetism Preserved in Lava Flows



The discovery of strips of alternating polarity, which lie as mirror images across the ocean ridges, is among the strongest evidence of seafloor spreading.

Polarity of the Ocean Crust



Ocean Drilling• The data on the ages of seafloor sediment confirmed what the

seafloor spreading hypothesis predicted.

• The youngest oceanic crust is at the ridge crest, and the oldest oceanic crust is at the continental edges.



Hot Spots• A hot spot is a concentration of heat in the mantle capable of

producing magma, which rises to Earth’s surface; The Pacific plate moves over a hot spot, producing the Hawaiian Islands.

• Hot spot evidence supports that the plates move over the Earth’s surface.

Hot Spot

Warm up April 7th

1. What is a subduction zone?

2. Explain Paleomagnetism:

3.Explain Convection Currents?

Causes of Plate Motion

9.5 Mechanisms of Plate Motion

Scientists generally agree that convection occurring in the mantle is the basic driving force for plate movement.• Convective flow is the motion of matter resulting from changes

in temperature.



Slab-Pull and Ridge-Push

• Ridge-push causes oceanic lithosphere to slide down the sides of the oceanic ridge under the pull of gravity. It may contribute to plate motion.

• Slab-pull is a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and “pulls” the trailing lithosphere along. It is thought to be the primary downward arm of convective flow in the mantle.



Mantle Convection

• The unequal distribution of heat within Earth causes the thermal convection in the mantle that ultimately drives plate motion.

• Mantle plumes are masses of hotter-than-normal mantle material that ascend toward the surface, where they may lead to igneous activity.

Mantle Convection Models

Chapter

1212 Geologic Time

Rocks Record Earth History

12.1 Discovering Earth’s History

Rocks record geological events and changing life forms of the past.

We have learned that Earth is much older than anyone had previously imagined and that its surface and interior have been changed by the same geological processes that continue today.

A Brief History of Geology


Uniformitarianism means that the forces and processes that we observe today have been at work for a very long time.

Relative Dating—Key Principles


Relative dating tells us the sequence in which events occurred, not how long ago they occurred.

Law of Superposition• The law of superposition states that in an undeformed sequence

of sedimentary rocks, each bed is older than the one above it and younger than the one below it.

Ordering the Grand Canyon’s History



Principle of Original Horizontality• The principle of original horizontality means that layers of

sediment are generally deposited in a horizontal position.

Disturbed Rock Layers



Principle of Cross-Cutting Relationships• The principle of cross-cutting relationships states that when a

fault cuts through rock layers, or when magma intrudes other rocks and crystallizes, we can assume that the fault or intrusion is younger than the rocks affected.

Inclusions• Inclusions are rocks contained within other rocks.

• Rocks containing inclusions are younger than the inclusions they contain.

Applying Cross-Cutting Relationships

Formation of Inclusions



Unconformities• An unconformity represents a long period during which

deposition stopped, erosion removed previously formed rocks, and then deposition resumed.

• An angular unconformity indicates that during the pause in deposition, a period of deformation (folding or tilting) and erosion occurred.

Formation of an Angular Conformity



Unconformities• A nonconformity is when the erosional surface separates older

metamorphic or intrusive igneous rocks from younger sedimentary rocks.

• A disconformity is when two sedimentary rock layers are separated by an erosional surface.

A Record of Uplift, Erosion, and Deposition

Correlation of Rock Layers


Correlation is establishing the equivalence of rocks of similar age in different areas.

Warm up April 13

• What is an unconformity?

• Explain Relative dating?

• What is the law of superposition?

• What is the Principle of Original Horizontality

Correlation of Strata at Three Locations

Fossil Formation

12.2 Fossils: Evidence of Past Life

Fossils are the remains or traces of prehistoric life. They are important components of sediment and sedimentary rocks.

• Some remains of organisms—such as teeth, bones, and shells—may not have been altered, or may have changed hardly at all over time.

The type of fossil that is formed is determined by the conditions under which an organism died and how it was buried.

Unaltered Remains

Fossil Formation


Altered Remains• The remains of an organism are likely to be changed over time.

• Fossils often become petrified or turned to stone.

• Molds and casts are another common type of fossil.

• Carbonization is particularly effective in preserving leaves and delicate animals. It occurs when an organism is buried under fine sediment.

Fossil Formation


Indirect Evidence• Trace fossils are indirect evidence of prehistoric life.

Conditions Favoring Preservation• Two conditions are important for preservation: rapid burial and the

possession of hard parts.

Types of Fossilization

Fossils and Correlation


The principle of fossil succession states that fossil organisms succeed one another in a definite and determinable order. Therefore, any time period can be recognized by its fossil content.

Index fossils are widespread geographically, are limited to a short span of geologic time, and occur in large numbers.

Fossil Formation


Interpreting Environments• Fossils can also be used to interpret and describe ancient

environments.For example, if you find marine fossils on top of a mountain, that is

a clue that the before it was a mountain the rock was once under an ocean.

Overlapping Ranges of Fossils

Basic Atomic Structures

12.3 Dating with Radioactivity

Orbiting the nucleus are electrons, which are negative electrical charges.

Atomic number is the number of protons in the atom’s nucleus.

Mass number is the number of protons plus the number of neutrons in an atom’s nucleus.

Radioactivity


Radioactivity is the spontaneous decay of certain unstable atomic nuclei.

Common Types of Radioactive Decay

Half-Life


A half-life is the amount of time necessary for one-half of the nuclei in a sample to decay to a stable isotope.

The Half-Life Decay Curve

Radiometric Dating


Each radioactive isotope has been decaying at a constant rate since the formation of the rocks in which it occurs.

Radiometric dating is the procedure of calculating the absolute ages of rocks and minerals that contain radioactive isotopes.

Radiometric Dating As a radioactive isotope decays, atoms of

the daughter product are formed and accumulate.


An accurate radiometric date can be obtained only if the mineral remained in a closed system during the entire period since its formation.

Warm up April 18th

• 1. Explain what the lab showed us from Last week Thursday?

• 2. Explain Radioactivity?

• 3. What is an index fossil?

Radioactive Isotopes Frequently Used in Radiometric Dating

Dating with Carbon-14 Radiocarbon dating is the method for

determining age by comparing the amount of carbon-14 to the amount of carbon-12 in a sample.


When an organism dies, the amount of carbon-14 it contains gradually decreases as it decays. By comparing the ratio of carbon-14 to carbon-12 in a sample, radiocarbon dates can be determined. The half-life of C-14 is 5,730 years.

Importance of Radiometric Dating Radiometric dating has supported the ideas

of James Hutton, Charles Darwin, and others who inferred that geologic time must be immense.


Warm up 4-14-11

• What are the 3 type of plate boundaries?

• What are the 4 different segments of time we use to brake up the geologic record?

• Explain Radio Carbon Dating.

• What is Half Life?

Structure of the Time Scale

12.4 The Geologic Time Scale

Based on their interpretations of the rock record, geologists have divided Earth’s 4.56-billion-year history into units that represent specific amounts of time. Taken together, these time spans make up the geologic time scale.



Eons represent the greatest expanses of time. Eons are divided into eras. Each era is subdivided into periods. Finally, periods are divided into smaller units called epochs.

There are three eras within the Phanerozoic eon: the Paleozoic, which means “ancient life,” the Mesozoic, which means “middle life,” and the Cenozoic, which means “recent life.”



Each period within an era is characterized by somewhat less profound changes in life forms as compared with the changes that occur during an era.

The periods of the Cenozoic era are divided into still smaller units called epochs, during which even less profound changes in life forms occur.

Precambrian Time


During Precambrian time, there were fewer life forms. These life forms are more difficult to identify and the rocks have been disturbed often.

The Geologic Time Scale

Difficulties With the Geologic Time Scale


A sedimentary rock may contain particles that contain radioactive isotopes, but these particles are not the same age as the rock in which they occur.

The age of a particular mineral in a metamorphic rock does not necessarily represent the time when the rock was first formed. Instead, the date may indicate when the rock was metamorphosed.

Using Radiometric Methods to Help Date Sedimentary Rocks

Chapter

1313 Earth’s History

Precambrian History

13.1 Precambrian Time: Vast and Puzzling

The Precambrian encompasses immense geological time, from Earth’s distant beginnings 4.56 billion years ago until the start of the Cambrian period, over 4 billion years later.

Precambrian Rocks• Shields are large, relatively flat expanses of ancient metamorphic

rock within the stable continental interior.

• Much of what we know about Precambrian rocks comes from ores mined from shields.

Geologic Time Scale

Remnants of Precambrian Rocks

Precambrian History


Earth’s Atmosphere Evolves• Earth’s original atmosphere was made up of gases similar to those

released in volcanic eruptions today—water vapor, carbon dioxide, nitrogen, and several trace gases, but no oxygen.

• Later, primary plants evolved that used photosynthesis and released oxygen.

• Oxygen began to accumulate in the atmosphere about 2.5 billion years ago.

Precambrian History


Precambrian Fossils• The most common Precambrian fossils are stromatolites.

• Stromatolites are distinctively layered mounds or columns of calcium carbonate. They are not the remains of actual organisms but are the material deposited by algae.

• Many of these ancient fossils are preserved in chert—a hard dense chemical sedimentary rock.

Stromatolites then and now

• Then

Now

Early Paleozoic

13.2 Paleozoic Era: Life Explodes

Following the long Precambrian, the most recent 540 million years of Earth’s history are divided into three eras: Paleozoic, Mesozoic, and Cenozoic.

Early Paleozoic


Early Paleozoic History• During the Cambrian, Ordovician, and Silurian periods, the vast

southern continent of Gondwana encompassed five continents (South America, Africa, Australia, Antarctica, and part of Asia).

Gondwana and the Continental Landmasses

Early Paleozoic


Early Paleozoic Life• Life in early Paleozoic time was restricted to the seas.

Life in the Ordovician Period

Late Paleozoic


Late Paleozoic History• Laurasia is the continental mass that formed the northern portion

of Pangaea, consisting of present-day North America and Eurasia.

• By the end of the Paleozoic, all the continents had fused into the supercontinent of Pangaea.

Late Paleozoic Plate Movements

Late Paleozoic


Late Paleozoic Life• Some 400 million years ago, plants that had adapted to survive

at the water’s edge began to move inland, becoming land plants.

• The amphibians rapidly diversified because they had minimal competition from other land dwellers.

Armor-Plated Fish

Model of a Pennsylvanian Coal Swamp

The Great Paleozoic Extinction


The world’s climate became very seasonal, probably causing the dramatic extinction of many species.

The late Paleozoic extinction was the greatest of at least five mass extinctions to occur over the past 500 million years.

Mesozoic Era

13.3 Mesozoic Era: Age of Reptiles

Dinosaurs were land-dwelling reptiles that thrived during the Mesozoic era.

Mesozoic History • A major event of the Mesozoic era was the breakup of Pangaea.

Mesozoic Era Mesozoic Life


• Gymnosperms are seed-bearing plants that do not depend on free-standing water for fertilization. Gymnosperms are plants that have cones.

• The gymnosperms quickly became the dominant plants of the Mesozoic era.

Gymnosperms

Canadian Rockies Were Formed Throughout the Cretaceous Period

Mesozoic Era The Shelled Egg


• Unlike amphibians, reptiles have shell-covered eggs that can be laid on the land.

• The elimination of a water-dwelling stage (like the tadpole stage in frogs) was an important evolutionary step.

Mesozoic Era Reptiles Dominate


• With the perfection of the shelled egg, reptiles quickly became the dominant land animals.

• At the end of the Mesozoic era, many reptile groups became extinct.

The Flying Reptile Pteranodon

Cenozoic North America The Cenozoic era is divided into two

periods of very unequal duration, the Tertiary period and the Quaternary period.

13.4 Cenozoic Era: Age of Mammals

Plate interactions during the Cenozoic era caused many events of mountain building, volcanism, and earthquakes in the West.

Cenozoic Life Mammals—animals that bear live young

and maintain a steady body temperature— replaced reptiles as the dominant land animals in the Cenozoic era.


Angiosperms—flowering plants with covered seeds—replaced gymnosperms as the dominant land plants.

Cenozoic Life Mammals Replace Reptiles


• Adaptations like being warm blooded, developing insulating body hair, and having more efficient heart and lungs allow mammals to lead more active lives than reptiles.

Fossils from La Brea Tar Pits

Cenozoic Life Large Mammals and Extinction


• In North America, the mastodon and mammoth, both huge relatives of the elephant, became extinct. In addition, saber-toothed cats, giant beavers, large ground sloths, horses, camels, giant bison, and others died out on the North American continent.

• The reason for this recent wave of extinctions puzzles scientists. 3 probable causes are: humans killed them off, climate change (end of ice age) and hyperdisease—humans and domesticated animals contained germs that jumped to the wild species.

Wooly mammoths

Mastodons

Warm up 2/8/11

• What are the 4 spheres

• 4 Major branches of earth Science

• Draw the boat on water example

• Three types of rocks

warm up january 10, 2012 1. what is the carbon cycle? 2. what are the 4 main branches of earth...

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