Unit 3.2 Test Review

Multiple Choice

Which process most directly leads to the formation of sedimentary rock layers where fossils are found?

• sedimentation

• concreting

• erosion

• fossilization

Sedimentation

Remember that sedimentary rocks can contain fossils. To form sedimentary rocks, you need sediment (aka dirt and sand). Hence, sedimentation.

Multiple Choice

Why are fossils most commonly found in sedimentary rocks rather than igneous or metamorphic rocks?

• Igneous rocks form from volcanoes, which cover dead bodies in lava, burning them.

• Metamorphic rocks form under extreme pressure and heat, resulting in changing fossils to new rocks

• Sedimentary rocks form from layers of sediments that can bury and preserve organisms.

• None of these are acceptable answers.

Sedimentary rocks

Quick burying in sediment is more likely to form fossils than any other method. That is not something seen in igneous or metamorphic rocks.

Multiple Choice

Explain why the fossil record is incomplete

• All organisms that ever lived eventually become fossils.

• Most organisms decompose before they can be fossilized

• Fossils are only found in volcanic rock, which is rare.

• Fossilization happens quickly to every dead organism.

Fossil Record

Most of the time, 99 times out of 100, most organisms die and are not fossilized. The conditions to fossilize are rather specific and this means that most of the time we don't get a fossil from a dead organism.

Multiple Choice

What is fossilization?

• Preserving the dead remains of organisms in rock.

• The slow movement of plates around on the Earth's surface

• When new species evolve from other species, resulting in new physical traits

• The breakdown of rock into smaller peices

Fossilization

Taking the body or remains of a dead organism and preserving them in amber or mineral form is known as fossilization.

Multiple Choice

How does speciation affect the fossil record?

• It prevents any new fossils from forming.

• It causes all older fossils to disappear from the record.

• It makes it impossible to identify relationships between species.

• More kinds of organisms means more chances for fossilization.

Speciation

Speciation is the evolution of new species. This results in new, unique organisms that fossilize and appear in the fossil record.

Multiple Choice

Why might scientists find more fossils from marine organisms than land organisms?

• Because marine organisms fossils easier than land organisms.

• Because land organisms are more common than marine organisms.

• Because land organisms fossils easier than marine organisms.

• Because both land and marine organisms fossils in the same manner.

Marine vs. Land

Remember that marine fossils are more likely because they are more likely to be buried in sediment without being scavenged. Unlike land animals.

Multiple Choice

What is a biozone in the rock record?

• A zone in rocks where only volcanic material is found.

• A section of rock that contains no evidence of past life.

• A layer of rock identified by the presence of specific fossil species.

• A region of rock that changes color due to weathering.

Biozone

A biozone is the specific appearance of a specific fossil in the rock strata. The biozone is defined by when the fossil first appears and when the organism that makes the fossil goes extinct.

Multiple Choice

The concept of faunal succession means what?

• All types of fossils are randomly distributed in rock layers.

• Fossil organisms appear in a consistent, recognizable order through rock layers over time.

• Only land animal fossils are found in the oldest rocks.

• Fossils from different time periods are always found together in the same layer.

Faunal Succession

Faunal Succession describes how one species replaces a previous species in the fossil record. Trilobites are replaced by Ammoniates are replaced by Squid, for example.

Multiple Choice

How can fossils in rock layers help scientists learn about past environments?

• Fossils show how rocks change color over time.

• The types of fossils found indicate what the environment was like when the rock formed.

• Fossils tell scientists the exact age of every rock layer.

• Fossils form only in dry, desert environments.

Fossils and Ancient Environments

Fossils give us clues to ancient environments. Coral fossils indicate shallow seas, palm tree fossils indicate warm climates, etc.

Multiple Choice

If scientists find forest fossils, such as trees or ferns, in rock layers deep in the desert, what does this suggest?

• The area was once a forest

• The fossils were moved from another location

• The fossils are old, due to superposition

• The fossils are young, due to cross-cutting relationships

Clues about ancient environments

If an area has forest fossils, it must have been a forest in the past. Even if it is currently a desert. Climate change and plate tectonics moves continents around, resulting in things like ocean fossils appearing on land.

Multiple Choice

How do changes in fossil types from one layer to the next demonstrate the dynamic nature of Earth?

• They prove that Earth’s surface has never changed.

• They indicate that all species have existed unchanged since the beginning.

• They show that species and environments have changed over time.

• They suggest that fossils can form spontaneously in any layer.

Changes in fossils

Changes in fossil types, such as faunal succession, shows us that life on Earth is not static, but instead it is dynamic and changes over time.

Multiple Choice

If a fossil of a cold weather plant is found in an area that is now tropical and wet, what conclusion can scientists draw?

• The area had a cooler climate when the plant was alive.

• The plant evolved to live in tropical climates without changing the climate.

• The fossil must have been transported from a different continent recently.

• The climate has never changed in that region.

Cold weather fossils

Just like changes in fossils from forest to desert indicates a change in climate, changes from cold weather plants to warm weather plants also indicates a change in climate.

Multiple Choice

What evidence in the fossil record best supports the occurrence of a mass extinction event?

• The sudden appearance of a large number of new fossils species

• The sudden disappearance of a large number of fossil species

• The random change over time of fossils species from old to new

• None of these answers are acceptable or correct

Mass extinction

A mass extinction is when a large number of species goes extinct suddenly. This can be due to a number of different factors, such as volcanoes and asteroids.

Multiple Choice

What does a sharp boundary between rock layers containing different fossil groups suggest?

• Fossils from different layers are actually the same age.

• The rock layers formed at exactly the same time.

• Fossils can only form in one type of rock.

• There was a rapid change in the environment or a mass extinction event.

Mass extinction part 2

If there is a sudden change or turnover in the type of species. For example dinosaurs are suddenly replaced by mammals, then a mass extinction has happened. This may be due to climate change.

Multiple Choice

How can scientists use rock and fossil evidence to identify major climatic changes in Earth’s history?

• Different fossils and rock types indicate past environments, showing how climate changed over time.

• All rocks and fossils form in the same climate, so they cannot indicate change.

• Fossils can only show the age of rocks, not climate.

• Rocks and fossils provide information only about earthquakes, not climate.

Rocks, Fossils, and Climate

The combination of fossils + rock type gives us insight into the climate in the ancient past. For example, finding wide spread fossils of forest trees indicates forests were widespread at that time.

Multiple Choice

How do mass extinctions affect the fossil record?

• They ensure that all species continue to appear without interruption.

• They create gaps in the fossil record by causing many species to disappear rapidly.

• They prevent fossils from forming in the future.

• They only affect fossils of plants, not animals.

Mass Extinctions part 3

The fossil record provide us insights into changes in the types of species that have been alive on Earth, and when those species go extinct that to provides us clues into the conditions on Earth.

Multiple Choice

Why do scientists study patterns of extinction and recovery in the rock record?

• To understand how life on Earth responds to change

• To better grasp when organisms lived on Earth

• To categorize rocks according to their type: sedimentary, igneous, or metamorphic

• To find fossil fuels such as oil or coal

Mass Extinctions part 4

By understanding how extinction functions on Earth and how life responds to extinction, we better grasp how evolution and life works.

Multiple Choice

Examine the graph. Describe what is happening to life forms when there are mass extinction events.

• All species suddenly appear for the first time.

• Life forms remain completely unchanged.

• Many species die out in a relatively short period of time.

• Only small organisms go extinct while large ones are unaffected.

Mass Extinctions part 5

When the number of species dips rapidly on a graph, that indicates that there was a mass extinction at that time.

Multiple Choice

What sorts of conditions lead to ideal fossil formation?

• Rapid burial in sediment

• Slow burial in sediment

• Lava covering the organism

• Scavengers scattering the bones

Ideal fossil formation

Ideal fossil formation happens when organisms are rapidly buried in sediment/dirt after they die. This can be underwater or on land.

Multiple Choice

What sorts of events can cause fossils to not be formed?

• Fossils always form, so no events can prevent them.

• Only volcanic eruptions allow fossils to form.

• Freezing completely prevents fossilization in all cases.

• Rapid decay, erosion, or environments not conducive to fossilization.

Fossils not forming

Conditions like erosion, scavengers, fire, etc., can all result in a fossil not forming. Best conditions include rapid burial and being covered up so that the body isn't eaten.