Answers to End-of-Chapter Questions – Brooker et al ARIS site
Chapter 1
Test Yourself Questions
1. The process where living organisms maintain a relatively stable internal condition is
a. adaptation.
b. evolution.
c. metabolism.
d. homeostasis.
e. development.
Answer: d. Homeostasis is the process that allows living organisms to maintain a relatively stable
internal condition.
2. Populations of organisms change over the course of many generations. Many of these changes
result in increased survival and reproduction. This phenomenon is
a. evolution.
b. homeostasis.
c. development.
d. genetics.
e. metabolism.
Answer: a. Biological evolution refers to the changes that populations of organisms will accumulate over
many generations.
3. All of the places on the Earth where living organisms are found is the
a. the ecosystem.
b. a community.
c. the biosphere.
d. a viable land mass.
e. a population.
Answer: c. The biosphere encompasses all the land, air and water where living organisms are found.
4. Horizontal evolution is the result of
a. accumulation of mutations over many generations.
b. transfer of genetic material between individuals of different species.
c. transfer of genetic material from parent to offspring.
d. all of the above.
e. a and c only.
Answer: b. Horizontal evolution refers to the transfer of genetic information between individuals of
different species and not from parent to offspring.
5. The scientific name for humans is Homo sapiens. The name Homo is the _____ to which humans
are classified.
a. kingdom
b. phylum
c. order
d. genus
e. species
Answer: d. Humans are classified in the genus Homo.
6. The complete genetic makeup of an organism is called
a. the genus.
b. the genome.
c. the proteome.
d. the genotype.
e. the phenotype.
Answer: b. The genome is an individual’s complete genetic makeup.
7. A proposed explanation for a natural phenomenon is a
a. a theory.
b. a law.
c. a prediction.
d. a hypothesis.
e. an assay.
Answer: d. Scientists form hypotheses as possible explanations of natural phenomena.
8. In science, a theory should
a. be equated with knowledge.
b. be supported by a substantial body of evidence.
c. provide the ability to make many correct predictions.
d. all of the above.
e. b and c only.
Answer: d. Scientific theories are supported by vast amounts of data and allow us to make many
predictions. Biologists view theories as knowledge.
9. Conducting research without a preconceived hypothesis is called
a. discovery-based science.
b. the scientific method.
c. hypothesis testing.
d. a control experiment.
e. none of the above.
Answer: a. Discovery-based science does not require a hypothesis.
10. What is the purpose of using a control in scientific experiments?
a. A control allows the researcher to practice the experiment first before actually conducting it.
b. A researcher can compare the results in the experimental group and control group to
determine if a single variable is causing a particular outcome in the experimental group.
c. A control provides the framework for the entire experiment so the researcher can recall the
procedures that should be conducted.
d. A control allows the researcher to conduct other experimental changes without disturbing the
original experiment.
e. All of the above.
Answer: b. Control experiments or samples are used for comparison with the experimental samples to
determine if a particular variable causes a particular outcome.
Conceptual Questions
1. List the seven characteristics of life and explain a little about each.
Answer:
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Cells and organization – all living organisms consist of cells; organisms maintain an internal
order that is separated from the environment.
Energy use and metabolism – all living organisms acquire energy from the environment and use
that energy to maintain their internal order. An organism’s chemical reactions are collectively
known as metabolism.
Response to environmental changes – living organisms respond to environmental changes.
These responses are adaptations.
Regulation and homeostasis – living organisms maintain relatively stable internal conditions,
homeostasis.
Growth and development – growth produces more or larger cells; development produces
organisms with a defined set of characteristics.
Reproduction – to sustain life, organisms must produce others like themselves; the genetic
material maintains continuity over the generations.
Biological evolution – populations of organisms change over the course of many generations.
2. Give the levels of organization from the simplest to most complex.
Answer: Atoms, molecules and macromolecules, cells, tissues, organs, organisms, populations,
communities, ecosystems, biosphere.
3. List the taxonomic groups from most inclusive to least inclusive.
Answer: Domain, kingdom, phylum, class, order, family, genus, species.
Experimental Questions
1. Discuss the difference between discovery-based science and hypothesis testing.
Answer: In discovery-based science, a researcher does not need to have a preconceived hypothesis.
Experimentation is conducted in the hope that it may have practical applications or may provide new
information that will lead to a hypothesis. By comparison, hypothesis testing occurs when a researcher
forms a hypothesis that makes certain predictions. Experiments are conducted to see if those
predictions are correct. In this way, the hypothesis may be accepted or rejected.
2. What are the steps in the scientific method, also called hypothesis testing?
Answer: This strategy may be described as a five-stage process:
1. Observations are made regarding natural phenomena.
2. These observations lead to a hypothesis that tries to explain the phenomena. A useful
hypothesis is one that is testable because it makes specific predictions.
3. Experimentation is conducted to determine if the predictions are correct.
4. The data from the experiment is analyzed.
5. The hypothesis is accepted or rejected.
3. When conducting an experiment, explain how a control sample and an experimental sample differ
from each other.
Answer: In an ideal experiment, the control and experimental samples differ by only one factor.
Biologists apply statistical analyses to their data to determine if the control and experimental samples
are likely to be different from each other because of the single variable that is different between the two
samples. This provides an objective way to accept or reject a hypothesis.
Collaborative Questions
1. Discuss the terms genomes and proteomes.
Answer: The term genome refers to the complete genetic makeup of an organism. It is essential for life
because it acts as a stable informational unit and provides continuity from generation to generation. It
also acts as an instrument for evolutionary change. By studying the genome of an organism, we can
examine the result of millions of years of evolution.
The term proteome refers to the complete complement of proteins that a cell or organism can make.
These proteins help the cell maintain cell structure and carry out most of the functions in a cell.
Therefore, by studying the proteome, we can understand how the various levels of biology are related to
one another and how the functioning of proteins produces the characteristics of cells and organisms,
and how organisms survive in their natural environments.
2. Discuss the levels of organization of life.
Answer: The organization of living organisms can be analyzed in a hierarchical manner, starting with the
very small and progressing to levels that are much larger and more complex. Different branches of
science study each of these levels.
Atoms – All living things are composed of atoms.
Molecules – At this level, scientists study the basic building blocks of all living organisms. Molecular
biologists examine proteins, carbohydrates, lipids, and nucleic acids at this level.
Cells – Molecules combine to form larger units called cells. All living things are made of at least one cell;
multicellular organisms are composed of many cells. Cell biologists are interested in cell structure and
function.
Tissues – Groups of cells of the same type associate with each other to function as a unit. Cell
biologists examine how cells are organized within tissues.
Organs – An organ is composed of two or more types of tissue. These tissues work together to perform
a specific function. For example, an animal physiologist might examine how the heart is composed of
nervous, muscle, epithelial, and connective tissues, and how these tissues work together to perform a
single function.
Organism – At this level, we look at living things that can be made up of a single cell such as a
bacterium, or something that is multicellular, such as a fish.
Populations – Groups of individuals constitute a population. Ecologists study populations in nature.
Evolutionary biologists want to understand how populations evolve over the course of many
generations.
Community – This is an assemblage of populations of different species. Ecologists and evolutionary
biologists are interested in the ways that species interact with each other.
Ecosystem – The ecosystem includes not just living organisms, but environmental conditions as well.
Ecologists also want to understand how environmental factors affect the survival of species.
Biosphere – As an ultimate goal, biology seeks to understand the biosphere, which includes all of the
places where life is found.