EHreview

Below is a diagram modeling fossil evidence found over geologic time.

Which of the following best explains why fossil evidence from each era has different organisms?

• Major mass extinctions of organisms occurred at the end of each era allowing new species to evolve.

• Organisms adapted to the new environment rapidly by the end of each era creating new species.

• Organisms evolved before the end of each eon creating new species.

• Major mass extinctions of organisms occurred in the middle of each era allowing new species to evolve.

The diagram below is a cross-section of sedimentary rock.

• Layer B is older than layer D.

• Layer C is older than layer A.

• Layer F is older than layer D.

• Layer D is older than layer A.

The picture below represents layers of sedimentary rock.

If fossils in layer 9 were identified as being from the Mesozoic Era, what can you best infer about fossils from layer 1?

• They may be from the Cenozoic Era.

• They may be from the Paleozoic Era.

• They may be from the Quaternary Period.

• They may be from the Tertiary Period.

The table below shows the dates and appearance of several fossils over geologic time.

Which of the following fossils would be the best index fossil?

• Fossil 1 because it lived in the most recent part of geologic time.

• Fossil 2 because it lived the longest amount of geologic time.

• Fossil 3 because it lived in the most distant part of geologic time.

• Fossil 4 because it lived the shortest amount of geologic time.

Scientists hypothesize that many dinosaurs went extinct during the Mesozoic Era due to the impact of an asteroid or comet.

Which of the following statements best explains how an impact of an asteroid or comet could have affected the conditions on Earth and the diversity of its life-forms during this mass extinction event?

• An impact could have caused dust and smoke to rise into the atmosphere causing rapid climate changes.

• An impact could have caused the movement of landmasses causing rapid climate changes.

• An impact could have increased earthquake activity, causing the extinction of most dinosaur species.

• An impact could have directly hit many organisms causing the extinction of most dinosaur species.

The graph below represents the climate changes over the past 65 million years on Earth during the Cenozoic Era.

Which of the following best explains how climate changes on Earth during the Cenozoic Era impacted the diversity of life?

• Ice ages and glaciers have influenced the evolution of many species.

• Polar climates and rising sea levels caused biodiversity on Earth to decrease.

• Tropical climates and warm shallow seas caused biodiversity to decrease.

• Human activities increased temperatures on Earth influencing the evolution of many species.

The graph below represents the number of extinction occurrences of organisms over millions of years.

What is the best explanation for the peaks in the graph?

• Major changes in the environment occurred primarily due to natural factors.

• Major epidemics of infectious diseases caused sickness to many types of organisms.

• Variations occurred in the amount of solar radiation that reached Earth.

• The effects of human population growth on the environment.

The picture below is petrified wood

What is the best explanation for how this fossil was formed?

 

• The wood was pressed between layers of soft mud or clay that hardened, squeezing almost all the decaying wood away and leaving the carbon imprint in the rock.

• Minerals soaked into the buried remains of a piece of wood, replacing the remains and changing them into a rock.

• Sediments buried a piece of wood and the sediments changed into a rock; the wood decayed leaving a cavity in the shape of the wood.

• A mold of a piece of wood was filled with sand or mud that hardened into the shape of the wood.

Below are images showing the possible ancestry of whales from fossil records.

What is the most likely reason for the changes seen over time from the early ancestor to the modern whale?

• The whale is more likely to survive in water with flippers rather than legs.

• The legs of the early ancestors were not needed in water so they eventually fell off.

• The early ancestor mated with fish-like animals and the offspring became whales.

• The early ancestors died off and whales migrated into the same ecosystem.

The limbs of several organisms are shown in the illustration below. Scientists sometimes compare the limbs of these organisms as evidence for common ancestry.

How do these limbs provide evidence of common ancestry?

• They have the same basic structure.

• They perform the same function.

• They are the same size and shape.

• They all have the same names for each bone.