Test Prep for AP® Courses

44.

Students analyze pollen grains and fern spores recovered from sediments taken below and above the Cretaceous-Paleogene boundary. Their results are summarized in the graph.

This is a graph with time on the x-axis, labeled Cretaceous on the left and Early Paleogene on the right, and percent relative abundance on the y-axis. Both axes are drawn as arrows extending to the right for the x-axis and upwards for the y-axis. The K-P g boundary is indicated with an arrow pointing to the space between the Cretaceous and Early Paleogene labels. The first line represents Fern spores and increases during the Cretaceous, drops to zero on the x-axis at the K-P g boundary, increases a smaller amount, and then decreases. The decrease slows and becomes more level by the end of the x-axis. The second line represents Angiosperm pollen grains. It increases to a peak just before the K-P g boundary, and then drops to zero on the x-axis before increasing a little, decreasing a little, becoming relatively level, and then increasing rapidly at the very end of the graph. On the right side of the graph, the second line representing Angiosperm pollen grains is still slightly below the first line representing Fern spores.

  1. The mass extinction event reduced only the angiosperms.
  2. Based on their reduced pollen counts found in the samples, the mass extinction event clearly reduced the number of ferns and angiosperms.
  3. The mass extinction affected only the ferns.
  4. Ferns were more abundant after the Cretaceous-Paleogene (K-Pg) mass extinction than before.
45.

Analyze the graph.

This is a graph with time on the x-axis, labeled Cretaceous on the left and Early Paleogene on the right, and percent relative abundance on the y-axis. Both axes are drawn as arrows extending to the right for the x-axis and upwards for the y-axis. The K-P g boundary is indicated with an arrow pointing to the space between the Cretaceous and Early Paleogene labels. The first line represents Fern spores and increases during the Cretaceous, drops to zero on the x-axis at the K-P g boundary, increases a smaller amount, and then decreases. The decrease slows and becomes more level by the end of the x-axis. The second line represents Angiosperm pollen grains. It increases to a peak just before the K-P g boundary, and then drops to zero on the x-axis before increasing a little, decreasing a little, becoming relatively level, and then increasing rapidly at the very end of the graph. On the right side of the graph, the second line representing Angiosperm pollen grains is still slightly below the first line representing Fern spores.

What are the reasons for the fern spike seen in the early Paleogene, considering ferns were the first plants seen on the ground after the volcanic eruption of Krakatoa and Mt. St. Helens? Propose reasons for the observed increase in fern spores following the mass extinction.

  1. Ferns are considered early colonizers as they grow fast on poor soil and reproduce rapidly. Also, mass extinction gave an opportunity for the surviving species to expand and radiate to occupy vacated niches.
  2. Ferns, having a selective advantage of being early colonizers, grew fast on poor soil and reproduced rapidly, thus permanently replacing angiosperms in the landscape.
  3. Ferns are considered early colonizers as they grow fast on poor soil and reproduce rapidly. The mass extinction barely lowered their numbers due to their resilience.
  4. Most of the fern varieties became extinct, only a single species survived; therefore, the remaining fern spores had many vacated niches to occupy which lead to an increase in fern numbers.
46.

A group of students summarized information on five great extinction events. The students are sampling a site in search of fossils from the Devonian period. Based on the chart, what would be the most reasonable plan for the students to follow?

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Figure 38.19
  1. Searching horizontally rock layers in any class of rock and trying to find those that contain the greatest number of fossils.
  2. Collecting fossils from rock layers deposited prior to the Permian period that contain some early vertebrate bones.
  3. Looking in sedimentary layers next to bodies of water in order to find marine fossils of bivalves and trilobites.
  4. Using relative dating techniques to determine the geological ages of the fossils so they can calculate the rate of speciation of early organisms.
47.

Students are sorting fossils of angiosperm pollen grains, some recovered from layers below the Cretaceous-Paleogene boundary and some from layers above the Cretaceous-Paleogene boundaries. The pollen grains are sorted by morphology. The results are summarized in a table.

This table has three rows and three columns. There is a blank space for the first row of the first column. The first row gives the column labels. In the first row, the second column reads Average Number of Grains per meter squared and the third column reads Morphology. In the second row, the three columns from left to right read Below Cretaceous-Paleogene, 102, Many different shapes. In the third row, the three columns from left to right read Above Cretaceous-Paleogene, 30, A few common shapes.

Can you explain the results?

  1. The mass extinction that took place at the Cretaceous-Paleogene boundaries reduced the total number of organisms, shown by the presence of fewer shapes of pollen grains, and led to a loss of diversity, shown by the lower number of grains.
  2. The mass extinction that took place at the Cretaceous-Paleogene boundaries reduced the total number of organisms, shown by the presence of fewer pollen grains, and led to a loss of diversity, as shown by the presence of fewer shapes.
  3. The mass extinction that took place at the Cretaceous-Paleogene boundaries reduced the total number of organisms, shown by the lower number of pollen grains, but did not affect diversity.
  4. The mass extinction that took place at the Cretaceous-Paleogene boundaries led to a loss of diversity, shown by the presence of fewer shapes of pollen grains, but did not affect the total number of organisms.
48.

A dig in a farmland soil rich in calcium carbonate reveals numerous shells of bivalves, chips of corals, the partial imprint of a trilobite, and a few vertebrae dated to 250 million years ago. The table of extinction summarizes information on the five major extinction events.

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Figure 38.20

According to the table of extinction, which conclusion about the fossils is most reasonable?

  1. The trilobites were the first animals to conquer land.
  2. The rocks can be dated to the end of the Cretaceous period.
  3. The farmland was probably part of the seafloor in the Permian period.
  4. The fossils can be dated to the Ordovician period.
49.

The average temperatures varied during the Pleistocene as glaciation periods were followed by warm intervals. Using the graph and your existing knowledge, what happened to woolly mammoths and other cold-adapted megafauna 10,000 years ago to cause their extinction?

This is a graph with Thousands of years on the x-axis and Change in temperature in degrees Celsius on the y-axis. The x-axis ranges from 50 on the left to 0 on the right. The y-axis ranges from negative 10 at the bottom to 4 at the top. A dotted horizontal line crosses the graph at 0 on the y-axis. A double-headed horizontal arrow runs at about negative 9 on the y-axis from 50 to just before 10 on the x-axis. A second double-headed horizontal arrow labeled Holocene extends from the end of the first arrow to 0 on the x-axis. From left to right, a line begins at negative 6 on the y-axis and moves up and down in a jagged way to reach the first double-headed arrow at about negative 9 on the y-axis and 20 on the x-axis. The line then increases, reaches a peak of about 1 on the y-axis at about 9 on the x-axis, and then descends in a jagged way to 0 on the y-axis and 0 on the x-axis.

  1. Habitat destruction due to varying temperatures and over-hunting by humans leading to their extinction.
  2. Sudden increase in temperature and over-hunting by humans leading to their extinction.
  3. Gradual increase in temperature and over-hunting by humans leading to their extinction.
  4. Sudden increase in temperature and in predation by larger mammals leading to their extinction.
50.

In winter, lichens are the only food for the caribou herds that roam the tundra. As the average temperatures increase with climate change, the lichens are gradually being replaced by shrubs and trees in the southern parts of the tundra. The graph illustrates the changes in abundance of lichens and caribou over time in a regional forest of Canada.

This graph has year on the x-axis, ranging from 1970 to 2000 in increments of 10, and with Relative population size on the y-axis. A line labeled Lichen begins relatively high on the y-axis at year 1970, then decreases to about quarter of the way up the y-axis at time 2000. A line labeled Caribou begins about halfway up the y-axis at year 1970 and decreases along with the Lichen graph to a point only slightly above the x-axis at year 2000.

A line labeled Caribou begins about halfway up the y-axis at year 1970 and decreases along with the Lichen graph to a point only slightly above the x-axis at year 2000. Which statement best explains the changes in the caribou population between 1975 and 1980?

  1. The caribou population expanded after the population of lichens dropped.
  2. The decline of the caribou population and the lichen population are not related.
  3. The population of caribou decreased following the drop in lichen availability.
  4. The caribou population was eliminated once the lichens decreased.
51.

A chain within the food web in the Arctic Ocean is shown below:

Phytoplankton ─> zooplankton ─> arctic char/cod ─> ringed seal─> polar bear. A chain within the arctic food web on land is shown below: Lichen/shrub ─> Caribou/hare/small rodent ─> fox/lynx/bird of prey

If polar bears move to land to hunt due to loss of sea ice, what will happen to the balance of the food web?

  1. Polar bears, being top predators, will edge out the other consumers without gaining enough calories themselves.
  2. Polar bears, being secondary consumers, will edge out the other consumers without gaining enough calories themselves.
  3. Polar bears, being top predators, will edge out the producers without gaining enough calories themselves.
  4. Polar bears, being secondary consumers, will edge out the producers without gaining enough calories themselves.
52.

Historically, the Atlantic Ocean off Canada and the northeast United States has been some of the richest and most popular fishing grounds. Huge factory ships developed in the 1960s converged on the region from all over the world, attracted by the rich catches. The graph represents the population of cod in recent years.

This graph shows years on the x-axis and Capture of fish in millions of tons on the y-axis. The x-axis ranges from 1950 to 2010 in increments of 20. The y-axis ranges from 0 to 4 in increments of 1. A line representing Atlantic northeast cod begins at about 0 in 1950, stays relatively level until about 1980, and then increases to about 0.5 at about 1985 and remains there through 2010. A line representing Atlantic northwest code begins just below 1 in 1950, increases to a peak around 2 just before 1970, decreases to a low of about 0.75 at about 1975, increases to just above 1 around 1985, decreases to about 0.5 at about 1995, and then remains relatively constant through 2010. A line labeled Pacific code begins just above 2 in 1950, increases to just above 3 in about 1955, goes down and then up to a peak of 4 just before 1970, and then decreases in a jagged way to about 1.3 in 2010.

Based on the graph, what is the likely explanation for the collapse of the northwest cod?

  1. A tropical disease decimated the populations of cod.
  2. Overfishing led to the collapse of the cod population.
  3. The cod population migrated somewhere else.
  4. The cod population is going through its cycle of rise and fall.
53.

The graphs show the changes in the human population and the rate of extinction.

This graph of Human population with year on the x-axis and Population in billions on the y-axis. The x-axis ranges from 1750 to 2000 in increments of 50. The y-axis ranges from 0 to 8 in increments of 2. A vertical line extends up from the year 1950. The line representing population begins at about 0.9 on the y-axis at 1750 and increases relatively slowly through 1950, when it reaches about 2.5. It then increases much more rapidly to a peak of about 7 in 2000.

This graph of Extinctions with year on the x-axis and Number of extinctions since 1500 on the y-axis. The x-axis ranges from 1750 to 2000 in increments of 50. The y-axis ranges from 0 to 1,000 in increments of 200. A vertical line extends up from the year 1950. The line representing extinctions begins just above 0 on the y-axis at 1750 and increases relatively slowly through 1850, when it reaches about 100. It then begins to curve up more rapidly to a peak of about 780 in the year 2000.

Which statement most likely explains how the increase in human population could lead to a decrease in biodiversity?

  1. Every human added to the planet replaces a different species of organism.
  2. The more people inhabiting the planet, the more the average temperature increases, causing loss of other species.
  3. With the increase in population the demands for land, water, food, and energy increase, leading to the destruction of habitat.
  4. Increases in human population reduce the amount of land available for use by all species.