Answers SY2025-26 - 2002070 MJ Comprehensive Science 2 Sem 1 CRUnit Test

Living Things and the Environment Answers

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The picture shows the skull of an extinct aquatic animal and the skull of a present-day gray whale. Further testing of the skulls suggests that the extinct animal is an ancestor of the gray whale.

by showing that all populations can adapt and survive

by showing that only some organisms have common ancestors

by showing that populations change slowly over time

by showing that species can rapidly become extinct

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A scientist observes fossil evidence that leads her to believe that certain organisms have a common ancestor.Which observation most likely led to this conclusion?

She observed older fossils that contained many of the same minerals as the newer ones.

She found skeletons of modern organisms in the same area as fossilized organisms.

She observed a fossil with skeletal structures similar to certain modern organisms.

She found several fossils in rock layers directly below other fossils of similar size.

Which idea is most directly related to Lamarck’s beliefs about evolution?

A frog’s legs grow during its lifetime to help it jump farther, and it passes on the longer legs to its offspring.

Humans and primates are classified in the same genus because they have similar traits.

If a population is left to reproduce without limiting factors, it will outgrow its food supply.

In one area, brown moths are better adapted to the environment than white moths, so they survive and reproduce.

There are green and red bugs living in an area. As a result of an environmental change, birds that live in the same area grow in numbers. These birds eat the bugs, and they prefer the taste of the red bugs.

Green bugs will survive better and reproduce, so the bug population will evolve into mostly green bugs.

Red bugs will survive better and reproduce, but the bug population will evolve into mostly green bugs.

Green bugs will survive better and reproduce, but the bug population will evolve into mostly red bugs.

Red bugs will survive better and reproduce, so the bug population will evolve into mostly red bugs.

Which statement best compares a trace fossil to a fossil that forms as a result of an entire organism being trapped in amber?

Both show the exact structure of the organism.

Both require that the hard parts of the organism dissolve.

Both form as a result of the organism leaving imprints in sediment.

Both can possibly be used to study the organism's size.

Which example best illustrates a condition necessary for natural selection to occur?

Cheetahs have nearly identical genetic makeup.

Clownfish can lay a thousand eggs at a time.

Some bacteria have very specific temperature requirements.

A strawberry plant is able to reproduce asexually.

Due to a genetic mutation, a mouse is born with fur that is not as light as fur in other mice of the same population. This makes it easier for the mouse to blend into the environment.

The mouse with the mutation will not survive, and the trait will disappear from the population.

The mouse with the mutation will survive and reproduce, and the trait will spread over future generations.

The mouse with the mutation will not survive, but the trait will appear again in the next generation.

The mouse with the mutation will survive and reproduce, but the trait will disappear because it was caused by a mutation.

A scientist has a fossil that was found in a layer of rock close to Earth’s surface. He believes that the fossil is around 12,000 years old.Which method would best allow the scientist to confirm the actual age of the fossil?

finding another fossil in a deeper layer of rock

finding another fossil in the same layer of rock

using carbon/nitrogen absolute dating

using potassium/argon absolute dating

Kelli drew a diagram to compare cast and imprint fossils.

Involves minerals replacing remains of organism

Takes millions of years to form

Gives evidence of organism's activity

Involves mold filling with minerals and sediment

Which scenario would most likely result in the extinction of one or more species?

The water temperature of a pond decreases slightly, and the members of the pond populations adapt to the change.

The conditions are abnormally dry for one season in a desert, resulting in the deaths of a few members of a snake population.

A predatory fish is introduced into a lake, resulting in a dramatic decrease in the populations of smaller fish.

A new plant species begins growing in a forest, resulting in a new food resource for many animal populations.

Geralda is listing all the conditions under which natural selection occurs. So far, she has listed:The environment changes.Organisms in a population have different traits.Which other condition should she include in her list?

All organisms in the population adapt and reproduce.

The environment returns to normal after some time.

The environment can support only new organisms.

Only some of the organisms survive and reproduce.

Species X is an extinct animal. A scientist has discovered fossils of species X and compared them to species Y, a living animal that inhabits the same area where the fossils were found. The scientist has noted that the two animals share several physical characteristics.What can the scientist most likely conclude about the two types of animals?

Species X was better adapted to the environment.

Species X outcompeted species Y for food.

Species X is an early ancestor of species Y.

Species X mated with species Y and had unique offspring.

Compared to absolute dating, what is an advantage of relative dating?

A single fossil can be dated by itself.

The actual age of a fossil can be determined.

Fossils do not need to be arranged in different layers of rock.

There is no limit to the age range of the fossils being dated.

Which idea did Linnaeus contribute to the theory of evolution?

All living things inherit acquired characteristics.

Humans tend to reproduce at a faster rate than the food supply.

The goal of organisms is to adapt and to strive for perfection.

Organisms can be classified based on similar traits.

How were Lamarck’s and Darwin’s ideas most similar?

Both stated that humans should be studied as individuals.

Both stated that natural selection drives evolution.

Both stated that evolution occurs in an individual’s lifetime.

Both stated that traits were passed on to offspring.

A genetic mutation causes a squirrel to be born with much darker fur than its parents.

Because the trait was caused by a mutation, it will not be passed on to any offspring, resulting in the disappearance of the trait.

Because the trait was caused by a mutation, it will be passed on to offspring over many generations, resulting in a population of darker squirrels.

If the trait is unfavorable, it will be passed on to offspring over many generations, resulting in a population of darker squirrels.

If the trait is favorable, it will be passed on to offspring over many generations, resulting in a population of darker squirrels.

Which factor is most likely to contribute to the evolution of a species?

the stable environment in which species members live

the genetic variation within the species

the inability of species members to adapt

the reproductive difficulties of species members

The diagram shows fossils buried in layers of sediment.

The fossil in layer Z is the youngest.

The fossils in layers Y and Z are younger than the fossil in layer V.

The fossil in layer Y is older than the fossil in layer W.

The fossil in layer X is older than the fossil in layer Z.

Three different reptile skulls with a common ancestor show that the skull changed from having no holes behind the eye to having one hole, and then two holes behind the eye.What conclusion did scientists draw about the reptile?

The skull evolved as the reptile developed stronger jaws.

The reptile evolved from living in water to living on land.

The reptiles were different ages when they died.

The reptile was never properly preserved during fossil formation.

evolutionnatural selectionextinctionvariation

evolution

natural selection

extinction

variation

The diagram shows a football field that represents a geological time scale.Why are no organisms labeled between the end zone and 30 yard line on the left side of the field?

Scientists disagree about the fossils from this time period.

Scientists have not studied that part of the time scale.

There is very little fossil evidence for this time period.

There are too many fossils to name.

Alex listed the typical steps of fossil formation.1) An organism dies.2) The remains fall to the bottom of the ocean.3) The soft portions decay, and the hard portions remain.4) The sediment becomes rock.

After step 3, layers of sediment cover the dead organism.

After step 1, minerals dissolve the dead organism.

After step 4, layers of sediment cover the dead organism.

After step 2, minerals dissolve the dead organism.

Suppose a species of snake is living in a certain area. Some of the snakes in the population are black and some are orange. Over time, the area changes and the orange snakes have a harder time blending in with the environment. This makes it difficult for the orange snakes to catch food.According to Darwin’s theory of evolution, what will most likely happen to this snake population over time?

Most orange snakes will survive and reproduce, passing on their traits to their offspring. Few black snakes will remain in the population.

Most black snakes will survive and reproduce, passing on their traits to their offspring. The number of orange snakes in the population will not change.

The black snakes will survive and reproduce, passing on their traits to their offspring. Few orange snakes will remain in the population.

Most orange snakes will survive and reproduce, passing on their traits to their offspring. The number of black snakes in the population will not change.

Which best describes Darwin’s studies that led to the theory of evolution?

extensive research of an individual organism within a short period

extensive research of an individual organism over many years

observations and data collected within a short period

observations and data collected over many years

Which causes genetic variations and can result in different alleles?

predation rate

random mutations

competition

environmental changes

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Living Things and the Environment Answers

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