8th Grade Science Review

If a sexually reproducing organism has 28 chromosomes in its body cells, how many chromosomes did it inherit from each parent?

14

Imagine you collected the data below to study the age and location of rocks on the sea floor. A table, titled "Age and Location of Sea-floor Rocks". Rocks 10 km from a mid-ocean ridge are 300,000 years old; rocks 25 km from a mid-ocean ridge are 1,000,000 years old; rocks 40 km from a mid ocean ridge are 1,625,000 years old. Based on the chart above, if a rock is located about 50 km from the mid-ocean ridge, how old is it likely to be?

2,000,000 years old

Juan is studying fossils. His teacher wrote the following statements on the board and asked the students to put them in the correct order to describe how fossils are formed. 1. Minerals seep into the organism's body and replace it with stone. 2. The organism completely decomposes, leaving behind an imprint. 3. An organism dies and its body is covered with a layer of sediment. 4. Time passes, and sediment layers continue to build up on the organism. Which is the correct order of events for fossil formation?

3, 4, 1, 2

Sandra is making a poster of Earth's geologic history. She wants to include a timeline on her poster. Which date should Sandra use at the beginning of her timeline, to show Earth's formation in the solar system?

4.6 billion years ago

In 1897, a British scientist proposed that Earth was between 20 and 400 million years old. Based on radiometric dating, scientists now propose a different age for Earth. Based on the most current radiometric dating data, about how old is Earth?

4.6 billion years old

Which of the following provides structural evidence for evolution?

A comparison of similar bones in the legs of a human, a dog, and a bat.

How dœs a sex cell differ from a body cell?

A sex cell has half the amount of genetic material as a body cell.

Trace fossils are much more common than body fossils. Which of the following best explains why trace fossils are more common?

A single animal can leave thousands of traces in its lifetime but will leave only one body when it dies.

Which statement about a zygote that forms by fertilization is correct?

A zygote has a full set of chromosomes, half from each parent.

A scientist crosses a rabbit with short fur and a rabbit with long fur. Which of these outcomes would show that the trait for fur length is an example of incomplete dominance?

All the offspring have medium-length fur.

Fossils are the preserved remains or traces of plants and animals that have lived on Earth throughout Earth's history. How does the fossil record of animals compare to animals that exist today?

Animals in the fossil record are ancestors of animals that exist today.

Which of the following organisms could have evolved during the Precambrian Era?

Ask your teacher to describe the picture to you.

Look at the topographic map below. A topographical map of a surface feature of Earth. The map contains four labels: A, B, C, and D. Each label identifies a specific contour line on the map. "A" is line 80; "B" is an unknown elevation above line 120; "C" is line 100; "D" is line 120. Which labeled point on this map has the highest elevation?

B

Examine the Punnett square below. A Punnet Square. The x-axis is labeled B; B. The y-axis is labeled B; b. The top two squares are BB; BB. The bottom two squares are Bb; Bb. Which of the following choices gives the alleles of the parents shown here?

BB and Bb

Why do folded mountain belts sometimes form at convergent plate boundaries?

Because rock is compressed and forced upward

Which of the following statements about pedigrees is true?

Boxes typically represent males and circles typically represent females.

The geologic time scale is divided by several different spans of time. Which of the following divisions of time are all eras?

Cenozoic, Mesozoic, Paleozoic

How does meiosis I differ from meiosis II?

Chromosome number decreases by half as a result of meiosis I, but not as a result of meiosis II.

How do the chromosomes at the end of meiosis I compare with the chromosomes at the end of meiosis II?

Chromosomes have two chromatids at the end of meiosis I and one chromatid at the end of meiosis II.

The figure below shows the basic concepts of cell division. A diagram showing the basic process of cell division. Ask your teacher to describe the diagram to you. Which of these statements describes what happens during stage 1?

DNA is copied

Which statement best describes dinosaurs?

Dinosaurs died out because of a mass extinction at the end of the Mesozoic Era.

Why do most earthquakes take place at tectonic plate boundaries?

Earthquakes take place where the motion of tectonic plates transfers energy to rock.

What role did evolution play during the Cenozoic Era?

Evolution led to a greater diversity of living things, including humans.

How is meiosis related to sexual reproduction?

How is meiosis related to sexual reproduction?

Which of the following statements summarizes how the formation of the solar system was similar to the differentiation of Earth into layers?

In both processes, the densest materials moved to the center.

Sinkholes, like the one shown here, result from the erosion of bedrock. Overhead view of a large sinkhole that has opened up next to a residence. A portion of the building and property wall has collapsed into the sinkhole. What can you conclude about the rock in these areas?

It dissolves easily in water

During the Apollo space program, astronauts placed seismographs on the moon. Scientists used the data from these devices to create the graph below. A graph of the seismic wave speeds in the moon's interior. The x-axis shows the speed in kilometers per second, in increments of 2 km/s. The y-axis shows the depth of the moon's surface in kilometers. Ask your teacher to describe the graph to you. Based on the data, what can you conclude about the moon's interior?

It has a liquid outer core and solid inner core

Which of the following statements correctly defines geology?

It is the scientific study of the history of Earth and the processes that shape it.

The landform shown in the following picture can be found on every continent; they are even found in Africa. A frozen sheet of ice on water. The frozen sheet is in-between mountains. What conditions are necessary for this landform to form?

It must be cold, and more snow must fall than melts.

Which of these statements is true of asexual reproduction?

It produces offspring genetically identical to each other and requires one parent.

The law of crosscutting relationships states that a rock unit or geologic feature (such as a fault) is younger than any other rock unit that it cuts through. A fault has shifted the rocks in the diagram below. Ask your teacher to describe the diagram to you. Which of the following is the oldest feature in this rock column?

Layer 1

The diagram below shows a portion of the fossil record in sedimentary rock. Different rock layers and fossils are clearly visible. Four layers of sedimentary rock. Layer A on top has sea shells and a fish skeleton in it. Layer B has a nautilus shell and a fish skeleton. Layer C has a triceratops skeleton and a shell. Layer D is the bottom layer and has shells in it. Which layer of rock is the oldest?

Layer D is the oldest.

Which of the following happened in Precambrian time?

Life began to evolve on Earth

Loess is a very valuable resource. What characteristic of loess makes it so valuable?

Loess is rich in minerals.

Charles Darwin studied the finches of the Galapagos Islands and found that their beaks vary in shape and size. Illustrations of the head and beaks of four species of Darwin's finches. Each of the four finches has a particular shape of beak, ranging from a thin and pointed one to a large, broad, and deep beak.Illustrations of the head and beaks of four species of Darwin's finches. Each of the four finches has a particular shape of beak, ranging from a thin and pointed one to a large, broad, and deep beak.Illustrations of the head and beaks of four species of Darwin's finches. Each of the four finches has a particular shape of beak, ranging from a thin and pointed one to a large, broad, and deep beak.Illustrations of the head and beaks of four species of Darwin's finches. Each of the four finches has a particular shape of beak, ranging from a thin and pointed one to a large, broad, and deep beak. Darwin found that the finches that ate mostly insects had long, narrow beaks. Finches that ate mostly seeds had shorter, broad beaks to crush seeds. Which statement below best describes how natural selection resulted in the four types of finches shown above?

Over time, the finches that were born with beaks better suited to the available food supply in their habitats survived and reproduced.

The Permian mass extinction, during which approximately 90% of all marine life became extinct, occurred during which geologic era?

Paleozoic Era

The diagram below shows the results of crossing a pea plant with round seeds and a pea plant with wrinkled seeds. A round seed labeled Parent 1 next to a wrinkled seed labeled Parent 2. A line points down from them to four round seeds, labeled Offspring 1; Offspring 2; Offspring 3; Offspring 4. What can be determined from the results of the experiment?

Smooth shape is a dominant trait, and wrinkled shape is a recessive trait.

Snakes have traces of leglike structures that are not used for movement. Which of the following could you infer from this evidence?

Snakes share a common ancestor with animals that have legs.

Look at the figure below. A world map showing all the continents are together. Which explanation best summarizes the hypothesis shown in the figure?

The continents were once a large landmass named Pangaea, which broke apart and gradually drifted to the present-day locations of the continents

One of the first discoveries from seismic wave data was the boundary between the crust and mantle. This boundary marks a change in composition, which in turn affects density. The speed of both P waves and S waves increases at this boundary. Which of the following statements best describes the difference between the crust and the mantle?

The crust is less dense than the mantle

Which of these statements best describes what Charles Darwin observed on the Galápagos Islands?

The finch population on each island was unique

Which of these statements correctly describes a difference between sex-linked disorders and other inherited genetic disorders?

The genes for sex-linked disorders are found on a sex chromosome, but the genes for other inherited genetic disorders are found on other chromosomes.

Brandy knows that chromosomes behave differently in meiosis and mitosis. What do chromosomes do in meiosis but not in mitosis?

The homologous chromosomes form pairs.

Which of these statements most likely describes what happens if DNA is not duplicated during interphase?

The new cells would have an incorrect number of chromosomes

Which of the following is an advantage of asexual reproduction?

The organism can increase in number quickly

The alluvial fan shown in the following illustration formed as sediment began to drop out from a stream that could no longer carry all of its sediment. A river, labeled River is flowing into an area, labeled Plain. As the river nears the plain it becomes wider and wider. Which statement best explains why the stream could no longer carry all its sediment?

The speed of the water was too slow

A geologist is studying an area after an earthquake. She notices that two streams have changed course. A diagram of streams changing course after an earthquake. Ask your teacher to describe the diagram to you. A diagram of streams changing course after an earthquake. Ask your teacher to describe the diagram to you. What would most likely explain the movement of the streams?

The stream runs across a transform fault that was offset by the earthquake.

How does distance from the epicenter of an earthquake change the earthquake's effects?

The strongest effects are usually felt near the epicenter.

Which of these describes a likely reason why a species would become extinct after a major environmental change?

There are not enough members of the species born with a trait necessary to survive in the new environment.

In what way are eras different from periods?

They are longer spans of time

Index fossils are used to date rock strata that would otherwise be very difficult to date. Which of these statements describes a key characteristic of index fossils?

They existed for a short span of time

The depth of the boundary between the crust and the mantle varies from about 5 to 8 km under ocean basins and about 20 to 70 km under continents. How do scientists study the location of this boundary?

They study the behavior of seismic waves

A student drew the diagram below to show one kind of radioactive decay. A circle labeled Thorium-232 is at the top. Four arrows extend from this circle. Arrow 1 points to a large circle labeled Lead-108. Arrow 2 points to a smaller circle labeled Beta particles. Arrow 3 points to an even smaller circle labeled Alpha particles. Arrow 4 points to the smallest circle labeled H∂4 Which of the following statements correctly describes this decay process?

Thorium-232 is the parent isotope, and lead-208 is the daughter isotope.

Earth is approximately 4.6 billion years old. How do scientists determine this?

Using radiometric dating techniques on meteorites

When glaciers retreat, they leave behind huge blocks of ice. When these ice blocks melt, they can form kettle lakes. Why is it important for sediment to build up around the ice blocks in order for kettle lakes to form?

Without the sediment, the water would not stay contained

Which of these scenarios is an example of natural selection?

Wolves with thick coats survive a cold winter more than wolves with thin coats. Thick-coated wolves have more offspring the following spring.

Which sentence best describes the process of relative dating?

Younger fossils are on top of older fossils.

Carrie is studying the genes of two fruit flies in her lab. She knows what alleles they have. She wants to know the potential combinations of alleles their offspring could inherit. Which of these choices would help Carrie identify the potential combinations?

a Punnett square

During the Paleozoic Era, the Appalachian Mountains of eastern North America began to form. The map below shows Earth's continents at about 50 million years ago, after the breakup of the supercontinent Pangaea. Since then, North America has continued to move farther away from Africa and Eurasia. A map of the world just after Pangaea broke apart. North America and South America are shown close to the continents of Europe and Africa. The Appalachian Mountains are labeled. Based on this map, what most likely caused the Appalachian Mountains to form?

a collision between North America and Africa

Which of these choices best describes what a ratio shows?

a comparison between two quantities

Which statement best describes an index fossil?

a fossil used to establish the absolute age of a rock layer

Which of these choices describes a segment of DNA that determines a specific trait in a person, such as attached earlobes?

a gene

What is a geologic column?

a group of rock layers that are placed in order of their relative ages

Rhianna has a stream flowing through her farm. The sediment flowing in the stream is usually fine sand. After a storm, the sediment is a mixture of fine sand, coarse sand, and pebbles. What would Rhianna most likely observe?

a higher rate of erosion after a storm

Which provides the best definition of a topographic map?

a map showing natural and human-made features and the shape of Earth's surface by using lines to represent different elevations

The diagram below shows a human cell. A small bulb at one end attached to a long tail. What type of cell is this?

a sex cell

Look at the topographic map below. A topographic map. Region A is to the left near the label 13600. Region B is to the right near the label 13600. Region C is in the center near the label 14200. Region D is on the bottom near the label 14000. An up arrow labeled "N" is on the bottom right side. Which area is best represented by the letter B on this map?

a slope on the side of a mountain

A landslide formed a huge erosional feature on the side of a hill called a scarp. You want to learn more about this feature's shape and size, but you cannot go to the site. Which of the following maps would be the best option to learn this information?

a topographic map

Water can cause weathering, erosion, and deposition. Which provides an example of water causing the weathering of rock?

acid rain

During the year 2003, the number of earthquakes that occurred was higher than usual. The map below shows the locations of some of these earthquakes. A map of the world that identifies, using dots, the locations of major earthquakes that occurred in 2003. Ask your teacher to describe the concentrations and locations of the earthquakes that occurred in 2003. Where did the highest concentration of earthquakes occur?

along the edges of the Pacific Ocean

Which type of image would be expected to provide the greatest level of detail for someone studying vegetation types in a small region?

an aerial photograph taken from an airplane

On December 26, 2004, a major tsunami occurred in the Indian Ocean. The tsunami traveled from its point of origin to as far away as Africa—nearly 5,000 km. The map below shows the origin of the tsunami and the direction the waves traveled. A map titled December 2004 Tsunami. The following countries are shown ad the most affected and labeled Seychelles; Maldives; Sri Lanka; Bangladesh; Phuket Is.; Indonesia. A dot indicated the tsunami started just off the coast of northern Indonesia. Other places that are labeled are the Indian Ocean, Middle East, Australia, and Asia. What was the cause of this tsunami?

an earthquake beneath the ocean

Sand dunes are formed where wind deposits sand it has been carrying. The following diagram shows a sand dune. The arrows show four different wind directions. An illustration of a sand dune and arrows showing the directions of winds. Arrow T points directly to the windward side of the dune. Arrow Q points directly to its lee side. Arrow R points diagonally to the lee side. Arrow S points vertically downward. Which arrow shows the direction in which the wind was blowing to form this sand dune?

arrow T

The diagram below shows a cross that is similar to one of Mendel's pea plant crosses. A diagram that illustrates a cross between two heterozygous blue-flowered pea plants. Seventy-five percent of the offspring have blue fowers and 25% have white flowers. How is blue flower color inherited in the cross shown?

as a dominant trait

Which layer of Earth does a tectonic plate ride on top of?

asthenosphere

A species of rodent lives in a moist forest climate. Over time, the climate becomes drier and more desert-like. Which of these adaptations would most likely improve the chances that the rodent species could survive as its environment changes?

being able to eat plants that survive in the changed environment

The image below represents a satellite view. A satellite view of mountains and water. What type of land features are pictured in this image?

canyons

Which type of stress causes deformation that leads to earthquakes at convergent plate boundaries?

compression

In the early 1900s, a hypothesis was introduced that proposed a single large landmass broke into smaller landmasses and formed the continents, which drifted to their present locations. What is the name of this hypothesis?

continental drift

Marley has a vegetable garden in her yard. During a storm, heavy rain falls. The rain runs over the garden, and some of the soil is washed away. Which term best describes this movement of soil from one place to another?

erosion

The figure below shows an arch, a geologic formation made over a long period of time by a process that supports the principle of uniformitarianism. A large rock cliff over water. A hole is missing from the cliff. Which process below formed the arch shown in the figure?

erosion

The figure below shows an example of a geologic change that supports the principle of uniformitarianism. A large rock cliff over water. A hole is missing from the cliff. What geologic change is shown in the figure?

erosion

What is the break in a body of rock along which one block slides relative to another called?

fault

When an organism reproduces by budding, how does the new organism start growing?

from the outer surface of the parent organism

William discovered that two modern-day species have very similar DNA. He concludes that the two species are closely related. What type of evidence did William most likely use to reach his conclusion?

genetic evidence

Earth formed in a swirling disk of matter surrounding the sun. As particles in the disk collided and stuck together, they grew larger and some eventually became planets. What force was responsible for the collisions between these particles?

gravity

Landslides, rockfalls, and creep are examples of erosion and deposition by which agent of erosion?

gravity

Which of the following explains how the theory of plate tectonics is most beneficial to society in terms of safety?

helps locate areas that have a higher potential for earthquakes

Every organism has a set of instructions that determines its traits. Which term describes the process through which it receives this set of instructions?

heredity

Florida State University has a large collection of ice cores taken from the Antarctic. What can scientists learn by studying these ice cores?

history of Earth's climate

What can cause a chain of volcanic islands to form far from plate boundaries?

hot spots

A group of students made a key to help them remember how different organisms reproduce asexually. Ask your Teacher Which of the following organisms could be listed in the cell labeled 2?

hydra

Which of these lists presents the stages of the cell cycle in the correct order?

interphase, mitosis, cytokinesis

Which best describes a fossil that was discovered in rock at the base of a cliff?

it is likely older than a fossil discovered in rock at the top of the cliff

The following image shows a mammoth. An illustration of a mammoth. The mammoth has long trunk, two long, curving tusks, is covered in hair, has strong shoulders, large tœnails, a small tail, and small floppy ears. Which trait most suggests that the mammoth was adapted to live in a cold climate?

its thick, furry coat

What are tectonic plates?

large, slowly moving pieces of Earth's lithosphere

The diagram below shows a cross section of different rock layers. According to the law of superposition, the rock layer above another rock layer is younger than the one below. Ask your teacher to describe the diagram to you. According to the law of superposition, which numbered layer is the youngest?

layer 1

The following diagram shows rock layers that are cut by a fault and two bodies of rock (rock 1 and rock 2). Ask your teacher to describe the diagram to you. What are the relative ages of the features in order of oldest to youngest?

layer 1, rock 2, rock 1, fault

What is the main criterion that scientists use to decide where to place the boundaries between the major divisions of the geologic time scale?

major changes that are recorded in the fossil record

Which of these choices is the best definition of absolute dating?

measuring the age of an object in years using any method

There are long mountain belts that divide the sea floor and generate new sea floor as magma rises and erupts onto Earth's surface. What are these mountain belts known as?

mid-ocean ridges

What process dœs a multicellular organism use to replace its damaged body cells?

mitosis

Which type of cell division is a part of asexual reproduction?

mitosis

Which of the following is a type of mass movement caused by gravity?

mudslide

On which type of plate would you find thinner, denser rock?

oceanic plate

Which of these choices is the definition of allele?

one of the alternative forms of a gene

Darwin's theory of natural selection consists of four important parts. Which of these correctly lists the four essential parts of natural selection?

overproduction, genetic variation, selection, and adaptation

Which of these choices is an example of the way a geologist would use relative dating?

placing rock layers in order of oldest to youngest

In the diagram below, an earthquake is taking place. A cross-section diagram of a part of Earth's lithosphere. Point A is deep below the surface. It is surrounded by concentric waves. The waves are labeled "D". Point B, on the surface, is directly above point A. Line C runs directly across the surface, away from point B. Where is the focus of the earthquake located?

point A

The new cells would have an incorrect number of chromosomes

prophase

Which of the following is a source of heat in Earth's interior?

radioactive decay

Which of the following processes generated heat during Earth's formation that is still a source of heat in Earth's interior?

radioactive decay

The illustration below represents a satellite image of Earth. Satellite view of a surface feature of Earth. The feature is long, thin, and meandering. Which feature is shown in the middle of the picture?

rivers

While hiking in the mountains, Tanya observed a narrow and steep valley with a stream at the bottom of it. What most likely caused the valley to first form?

running water

Which of the following images of Earth's surface can only be taken from space?

satellite image

The evidence supporting continental drift supports plate tectonics, because plate tectonics is a modified, expanded version of continental drift hypothesis. In the mid 1900s, additional evidence was found that led to the development of the theory of plate tectonics. Which is an example of this additional evidence?

sea-floor processes

Which type of reproduction involves two parents and results in offspring that are not genetically identical to either parent?

sexual reproduction

Satellites are able to use sensors to detect infrared and visible radiation. What type of information collected from a satellite would be most beneficial to a meteorologist making a weather forecast in a given area?

shape and height of clouds

Which of the following is not considered evidence for evolution?

similarity among organisms that are members of the same species

The diagram below shows rock that is being deformed by one type of stress. A rock split down the middle with arrows pointing outward on both sides. What type of stress is shown in the diagram?

tension

In regards to a topographic map, what is relief?

the difference between the highest and lowest elevations on a map

To determine when a volcano erupted, Michael used a sample of a mineral that formed when the lava cooled and became solid rock. He measured the amount of argon-40 in the sample to find how much potassium-40 had decayed since the rock formed. What else would Michael need to know to find the age of the mineral in years?

the half-life of potassium-40

A geologist is studying three layers of sedimentary rock in an area. The layers have not shifted from their original positions. The geologist records the relative ages of the rocks. The bottom layer is listed as the oldest. The top layer is listed as the youngest. What did the geologist use to determine the relative ages of the rocks?

the law of superposition

Which of the following best defines heredity?

the passage of genetic instructions from one generation to the next

What is evolution?

the process by which inherited traits of a population change over many generations

Which of these descriptions is an example of an unused body structure?

the tiny leg bones found in snakes that have no legs

Why does cell division take place in single-celled organisms?

to reproduce and pass on genetic information

Which type of map would be the most useful to study the shape and size of an erosional land feature?

topographic map

GIS enables users to combine layers to customize information. If a hiker were planning to go into the wilderness to study rock types, which layers would be most helpful to the hiker?

topographic map and geologic map

Which of these choices describes two kinds of trace fossils?

tracks and burrows

Which of these cases provides embryological evidence that two species share a common ancestor?

two different species with similar patterns of early development

The figure below shows two spotted salamanders. They are the same species of salamander, but they live in different areas. Two spotted salamanders; one has small spots and the other has large spots. Which of these terms is used to describe the difference between them?

variation

An aerial photograph of Earth shows Earth's surface exactly as it looks to the human eye. What do the sensors that take aerial photographs most likely detect?

visible light

Which statement correctly describes groundwater?

water below Earth's surface

Earth's surface features slowly change over time. For example, sharp, jagged mountain ranges become lower and more rounded over time. What factor or factors is/are responsible for this change in their shape?

weathering and erosion

Earth's surface features slowly change over time. For example, sharp, jagged mountain ranges become lower and more rounded over time. What is responsible for this change in their shape?

weathering and erosion

The tallest sand dunes in North America are found in Great Sand Dunes National Park and Preserve in Colorado. These dunes were formed from the sand at the bottom of a dry lake bed. Which of the following agents is most likely responsible for the formation of the sand dunes?

wind