CHAPTER 14 ACTIVE READING WORKSHEETS
HISTORY OF LIFE
Section 14-1: Biogenesis
The figure below shows the steps in Pasteur’s experiment. Study the figure. Then answer the
questions that follow.
Read each question and write your answer in the space provided.
SKILL: Interpreting Graphics
One reading skill is the ability to interpret or understand graphs or tables that may
appear in text. The following questions test your ability to interpret information from
the figure.
1. What does the first flask contain?
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2. How does the broth change during the experiment?
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Circle the letter of the phrase that best completes the statement.
3. The experiment illustrated above suggests that
a. the broth was never properly boiled.
b. microorganisms in the air contaminated the broth.
c. the flask must be sealed to prevent contamination.
d. Both (a) and (b)
CHAPTER 14 ACTIVE READING WORKSHEETS
HISTORY OF LIFE
Section 14-2: Earth’s History
Read the passage below, which covers topics from your textbook. Answer the questions that
follow.
Methods of establishing the age of materials include the technique known as radioactive
dating. Recall that the atomic number of an element is the number of protons in the
nucleus. All atoms of an element have the same atomic number, but their number of
neutrons can vary. Atoms of the same element that differ in the number of neutrons they
contain are called isotopes.
Some isotopes have unstable nuclei, which tend to undergo radioactive decay; that is,
their nuclei tend to release particles, radiant energy, or both. Such isotopes are called
radioactive isotopes. Rates of decay of radioactive isotopes have been determined for
many isotopes. The length of time it takes for one-half of any size sample of an isotope to
decay is called its half-life.
Read each question and write your answer in the space provided.
SKILL: Identifying Main Ideas
One reading skill is the ability to identify the main idea of a passage. Frequently a main
idea is accompanied by supporting information that offers detailed facts about the main
idea.
1. What is radioactive dating?
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2. What causes an isotope to undergo radioactive decay?
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3. What does half-life refer to?
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Circle the letter of the word or phrase that best completes the sentence.
4. Isotopes undergoing radioactive decay may release
a. radiant energy.
b. particles.
c. carbon.
d. Both (a) and (b)
Skills Worksheet
History of Life
In the space provided, explain how the terms in each pair differ in meaning.
1. radioactive isotope, half-life
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2. biogenesis, spontaneous generation
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3. cyanobacteria, archaebacteria
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4. mass number, isotope
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History of Life continued
In the space provided, write the letter of the description that best matches the term or phrase.
_____ 5. radiometric dating
_____ 6. endosymbiosis
_____ 7. biogenesis
_____ 8. isotope
_____ 9. half-life
_____ 10. ribozyme
_____ 11. ozone
_____ 12. microsphere
a. length of time it takes for one-half of a
radioactive isotope to decay to a stable
form
b. substance in the atmosphere composed
of three oxygen atoms that absorbs
ultraviolet radiation
c. RNA molecule that can act as a catalyst
d. calculation of the age of an object by
measuring the proportions of radioactive
isotopes of certain elements
e. spherical structures composed of protein
molecules organized as a membrane
f. the theory that mitochondria and
chloroplasts evolved from symbiotic
prokaryotes
g. principle which states that all living
things come from other living things
h. atoms of an element that have different
numbers of neutrons in the nucleus
SECTION 14-1 REVIEW
BIOGENESIS
VOCABULARY REVIEW Define the following terms.
1. biogenesis _________________________________________________________
2. spontaneous generation _______________________________________________
3. vital force _________________________________________________________
MULTIPLE CHOICE Write the correct letter in the blank.
______ 1. One of the observations that led people to think that life could arise from nonliving
things was that
a. maggots turned into oval cases from which flies eventually emerged.
b. fish appeared in ponds that had been dry the previous season.
c. large fish developed from smaller fish, which hatched from fish eggs.
d. fish grew larger by eating other living things, such as flies.
______ 2. The purpose of the netting in Redi’s experiment was to prevent
a. maggots from leaving the jar.
b. air from leaving the jar.
c. adult flies from entering the jar.
d. bacteria from entering the jar.
______ 3. In the experimental group in Spallanzani’s experiment, the
a. broth remained clear.
b. flask contained no broth.
c. broth was not boiled.
d. flask was not sealed.
______ 4. Spallanzani’s opponents disagreed with his conclusion that microorganisms from the
air contaminated the boiled meat broth. They argued that Spallanzani
a. heated the flasks too long, killing the microorganisms in the broth.
b. heated the flasks too long, destroying the “vital force” in the air inside the
flasks.
c. waited too long before he sealed the flasks after heating them.
d. accidentally contaminated the broth when he sealed the flasks.
______ 5. In Pasteur’s experiment, the function of the curved neck on the flask was to prevent
a. air from entering the body of the flask.
b. air from leaving the body of the flask.
c. solid particles from entering the body of the flask.
d. broth from spilling out of the flask.
SHORT ANSWER Answer the questions in the space provided.
1. What observations made in the 1600s and 1700s led some people to believe that there was a
“vital force” in the air? _______________________________________________
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2. Why did Spallanzani boil the broth in his experiment? ______________________
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3. How did Pasteur’s experiment differ from Spallanzani’s experiment?
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4. How did Pasteur’s experiment answer the objections raised by supporters of the “vital force”
hypothesis? ________________________________________________________
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5. Critical Thinking How might the believers in spontaneous generation have disputed Redi’s
onclusion if Redi had not used a control group? ___________________________
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STRUCTURES AND FUNCTIONS The diagrams below illustrate steps in the control and
experimental groups of Spallanzani’s experiment. In the spaces provided, list the steps
in each group in their proper order. A step may be used in more than one group.
SECTIO
N 14-2
REVIE
W
EARTH’S HISTORY
VOCABULARY REVIEW Explain the relationship between the terms in each of the
following pairs of terms.
1. radioactive isotope, radioactive dating __________________________________
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2. radioactive decay, half-life ____________________________________________
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3. microsphere, coacervate ______________________________________________
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MULTIPLE CHOICE Write the correct letter in the blank.
______ 1. The age of Earth is estimated to be
a. about 700,000 years.
b. about 50 million years.
c. about 400 million years.
d. more than 4 billion years.
______ 2. Sulfur has an atomic number of 16. Therefore, the isotope sulfur-35 has
a. 19 protons and 16 neutrons.
c. 16 protons and 19 neutrons.
b. 35 protons and 16 neutrons.
d. 16 protons and 35 neutrons.
______ 3. When performing radioactive dating, scientists measure the
a. number of protons and neutrons in the nucleus of a radioactive isotope.
b. amount of a particular radioactive isotope contained in a material.
c. age of a living organism that is exposed to radioactive isotopes.
d. rate at which the mass of an object decreases over time.
______ 4. Carbon-14 dating is useful for estimating the age of
a. relatively young organic material.c. Earth.
b. old rocks.
d. the solar system.
______ 5. Researchers using the technique of Miller and Urey have been able to produce
a. amino acids and nucleotides.
c. ATP and mitochondria.
b. proteins and DNA.
d. cell membranes and simple cells.
SHORT ANSWER Answer the questions in the space provided.
1. Explain how the half-life of a radioactive isotope affects the usefulness of that isotope in
dating specific types of rocks. __________________________________________
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2. Why do some scientists think that areas protected from the atmosphere might have favored
the production of organic compounds on early Earth? ______________________
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3. Why was the discovery of microspheres and coacervates an important contribution to the
understanding of how life might have originated on Earth? ___________________
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4. Critical Thinking Does radioactive dating with isotopes of uranium and thorium provide an
estimate of the beginning, middle, or end of the period of Earth’s formation? Explain your
answer.
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STRUCTURES AND FUNCTIONS Use the figure to answer the following question.
The graph below represents the radioactive decay of an isotope. If the half-life of thorium230 is 75,000 years, how old is a rock that contains only 1/16th of its original thorium-230?
Show your calculations in the space below.