Name______Class______Date______

Section 1: The Fossil Record

Study Guide A

Key Concept

Fossils are a record of life that existed in the past.

Vocabulary

relative dating / isotope
radiometric dating / half-life

Main Idea: Fossils can form in several ways.

activity / minerals / preserved remains
amber-preserved fossils / natural casts

Use the words in the box to fill in the blanks in the chart below.

Type of Fossil / Description of Fossil Formation
1. / Organism trapped in tree resin that hardens after being buried.
2. / An impression is left in sediment, and minerals fill the impression in, recreating the original shape of
the organism.
3. trace fossil / Fossils that record the ______of an organism. Examples include nests, burrows, imprints of leaves, and footprints.
4.permineralized fossil / Fossils that occur when ______carried
by water are deposited around a hard structure, sometimes replacing the hard structure itself
over time.
5. / Organism becomes encased in materials such as ice or volcanic ash, or immersed in a bog.

Study Guide A continued

Use Figure 1.2 to fill in a sequence diagram that describes the process
of permineralization.

Main Idea: Radiometric dating provides an accurate estimate of a fossil’s age.

Choose the best answer to the question.

8.What is the main purpose of both relative dating and radiometric dating?

a.To determine how old a fossil is.

b.To determine where the fossil falls in the fossil record.

c.To determine whether the fossil is a missing link.

d.To determine Earth’s age.

9.What is the main difference between relative dating and radiometric dating?

a.Relative dating compares a fossil with the fossils of other plants and animals that are known to have lived in certain time periods.

b.Relative dating is based on other items found near the fossil, while radiometric dating is based on the fossil itself.

c.Relative dating is based on other species that are related to the species of the fossil, while radiometric dating is based on the soil nearby.

d.Relative dating is based on the half-life of isotopes, while radiometric dating is based on the placement of fossils near other fossils in layers of rock.

10.What sort of time span can be measured using radiometric dating techniques?

a.A recent time span, such as the last five years.

b.A time span that covers several decades.

c.A time span of hundreds of years.

d.A geologic time span such as hundreds of thousands of years.

Study Guide A continued

Vocabulary Check

Match each term with its definition.

11. Measures the actual age of a fossil / a. relative dating
12. Most elements have several of these. / b. radiometric dating
13. Measure of the release of radiation / c. isotope
14. Infers order in which groups of organisms existed / d. half-life

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Holt McDougal Biology1The History of Life

Study Guide ASection 1: The Fossil Record

Name______Class______Date______

Section 2: The Geologic Time Scale

Study Guide A

Key Concept

The geologic time scale divides Earth’s history based on major past events.

Vocabulary

index fossil / era / epoch
geologic time scale / period

Main Idea: Index fossils are another tool to determine the age of rock layers.

Choose the phrase that best completes the statement.

1.Index fossils are a tool used in

a.radiometric dating.

b.relative dating.

c.book indexing.

d.forming theories about evolution.

2.The best index fossils are those that are common, easy to identify and find,
and that

a.existed only for a short period of time.

b.existed for long periods of time.

c.existed only on certain continents.

d.existed only in Earth’s oceans.

Study Guide A continued

Main Idea: The geologic time scale organizes Earth’s history.

Look at Figure 2.2 to fill in the following classification tree.

Vocabulary Check

era / period / epoch

Fillintheblanksbelowusingthetermsinthebox.Youmayusesometermsmorethanothers.

______9. The smallest unit of geologic time

______10. Associated with rock systems

______11. Consists of two or more periods

______12. Lasts tens to hundreds of millions of years

______13. Lasts several million years

______14. Lasts tens of millions of years

______15. Most commonly used units of geologic time

______16. Examples include the Paleozoic, Mesozoic,
and Cenozoic

______17. Examples include the Cambrian, Jurassic,
and Quaternary

Study Guide A continued

Thenames oferascomefromearlyideasaboutlifeformspreserved asfossils.Label each era based on its definition:

______18. ancient life

______19. middle life

______20. recent life

Choose the word or phrase that best completes the sentence.

21.The geologic time scale represents the history of fossils / Earth.

22.The smallest units of geologic time are known as epochs / periods.

23.The largest units of geologic time are known as periods / eras.

24.Fossils of organisms that existed only during specific spans of time are called index / radioactive fossils.

25.Humans have existed for most of / very little of the geologic time scale.

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Holt McDougal Biology1The History of Life

Study Guide ASection 2: The Geologic Time Scale

Name______Class______Date______

Section 3: Origin of Life

Study Guide A

Key Concept

The origin of life on Earth remains a puzzle.

Vocabulary

nebula / ribozyme

Main Idea: Earth was very different billions of years ago.

Choose the best answer to complete the sentence.

1.Most scientists believe that

a.Earth is only a few thousand years old.

b.Earth is millions of years old.

c.Earth is billions of years old.

d.Earth is too old to measure.

Fill in the Main Idea Web with the descriptions of early Earth.

Study Guide A continued

Main Idea: Several sets of hypotheses propose how life began on Earth.

Fill in the blanks in the chart.

Hypothesis / Proof
I. ORGANIC MOLECULE HYPOTHESES
9. Miller- ______
experiment / Demonstrated ______compounds could be made by passing electrical current (to simulate lightning) through a closed system that held a mixture of gases (to simulate the early atmosphere).
10. Meteorite hypothesis / Showed that 19 ______found in a meteorite that fell near Murchison, Australia in 1969 are found in other places on Earth.
II. EARLY CELL STRUCTURE HYPOTHESES
11. Iron-sulfide ______hypothesis / Simulated in the lab, making a ______structure with compartments that could have acted as the first cell membranes.
12. ______membrane hypothesis / Discovery that lipid molecules spontaneously form membrane-enclosed ______.
III. RNA AS EARLY GENETIC MATERIAL
13. RNA world hypothesis / Theory that ______, not DNA, stored information in living things on early Earth.

Vocabulary Check

Match each term with its definition.

14.A cloud of gas and dust in space / ribozymes
15. An RNA molecule that can catalyze
specific chemical reactions / nebula

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Holt McDougal Biology1The History of Life

Study Guide ASection 3: Origin of Life

Name______Class______Date______

Section 4: Early Single-Celled Organisms

Study Guide A

Key Concept

Single-celled organisms existed 3.8 billion years ago.

Vocabulary

cyanobacteria / endosymbiosis

Main Idea: Microbes have changed the physical and chemical composition of Earth.

Choose the answer that best completes the statement.

1.Single-celled organisms changed early Earth’s surface by depositing

a.bacteria.

b.viruses

c.DNA

d.minerals

2.The oldest fossils are of bacteria that can carry out

a.photosynthesis.

b.reproduction.

c.evolution.

d.genetic variation.

Main idea: Eukaryotic cells may have evolved through endosymbiosis.

Circle the word or phrase that best completes the sentence.

3.Prokaryotic / eukaryotic cells arose about 1.5 billion years ago.

4.Eukaryotes have a nucleus / half-life and membrane-bound organelles.

5.Eukaryotes are aerobic / anaerobic, which means they need oxygen to survive.

6.All cells in multicellular organisms today are prokaryotic / eukaryotic.

Study Guide A continued

Use the sequence diagram below to summarize the theory of endosymbiosis.

Choose the best answer to the question.

9.How do scientists theorize that cyanobacteria affected the development of endosymbiosis?

a.By providing waste matter to fertilize marine environments.

b.By providing oxygen that allowed prokaryotes to evolve.

c.By competing with prokaryotes for the food supply.

d.By competing with prokaryotes for the supply of oxygen.

Main Idea: The evolution of sexual reproduction led to increased diversity.

Choose the best answer to the question.

10.What is the main advantage of asexual reproduction?

a.genetic variation

b.produces many offspring quickly

c.mitochondria

d.requires a partner

11.What is the main advantage of sexual reproduction?

a.genetic variation

b.produces many offspring quickly

c.mitochondria

d.requires a partner

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Holt McDougal Biology1The History of Life

Study Guide ASection 4: Early Single-Celled Organisms

Name______Class______Date______

Study Guide A continued

Vocabulary Check

endosymbiosis / cynanobacteria

Fill in each blank with a word from the box. Use each word more than once.

______12.bacteria that can carry out photosynthesis

______13.the oldest known fossils

______14.a relationship in which one organism lives within the body of another, and both benefit

______15.the process through which eukaryotic cells may have first developed

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Holt McDougal Biology1The History of Life

Study Guide ASection 4: Early Single-Celled Organisms

Name______Class______Date______

Section 5: Radiation of Multicellular Life

Study Guide A

Key Concept

Multicellular life evolved in distinct phases.

Vocabulary

Paleozoic / Mesozoic
Cambrian explosion / Cenozoic

Main Idea: Life moved onto land during the Paleozoic era.

Fill in the gaps in the Main Idea and Supporting Information Diagram describing the Paleozoic era.

animal / Cambrian explosion / land

Main Idea: Reptiles radiated during the Mesozoic era.

Mammals / marsupials / water

Fill in the gaps in the Main Idea and Supporting Information Diagram describing the Mesozoic era.

Study Guide Acontinued

Main Idea: Mammals radiated during the Cenozoic era.

Homo sapiens / placental mammals / Tertiary
early ancestors of humans / Quaternary

Fill in the gaps in the Main Idea and Supporting Information Diagram describing the Cenozoic era.

Vocabulary Check

Fill in the blank with the term from the box that best fits the description.

Paleozoic / Cambrianexplosion / Mesozoic / Cenozoic

______10. Divided into the Triassic, Jurassic, and Cretaceous periods

______11. Ended with a mass extinction with more than 90 percent
of all marine life extinct

______12. Earliest part of Paleozoic era

______13. Primates evolved during this era

______14. Trilobites were abundant then

______15. Rise of the first marsupial mammals

______16. Divided into Tertiary and Quaternary periods

______17. Life moved onto land

______18. Includes the Carboniferous period

______19. Dinosaurs roamed the earth

______20. Continues today

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Holt McDougal Biology1The History of Life

Study Guide ASection 5: Radiation of Multicellular Life

Name______Class______Date______

Section 6: Primate Evolution

Study Guide A

Key Concept

Humans appeared late in Earth’s history.

Vocabulary

primate / hominid
prosimian / bipedal
anthropoid

Main Idea: Humans share a common ancestor with other primates.

Use Figure 6.2 to help you fill in the Concept Map below with the correct primate group. A few are already filled in for you.


Study Guide Acontinued

Main Idea: There are many fossils of extinct hominids.

Choose the best answer for the question.

11.Most hominids are classified into two groups: the genus Australopithecus and the genus

a.H. neanderthalensis

b.H. sapiens

c.Homo

d.A. afarensis

12.What early hominid was known as “handy man”?

a.Homo habilis

b.Homo sapiens

c.Homo neanderthalensis

d.Australopithecus afarensis

13.What early hominid group may have existed alongside modern humans?

a.Homo habilis

b.Homo sapiens

c.Homo neanderthalensis

d.Australopithecus afarensis

Main Idea: Modern humans arose about 200,000 years ago.

Choose whether the statement is true or false.

14.true / false Modern humans are thought to have evolved around 100,000 years ago in what is now Ethiopia.

15.true / false Culture, not just environmental factors, seems to play a role in human evolution.

Study Guide Acontinued

Vocabulary Check

anthropoid / hominid / primate / prosimian

______16. Walks upright, has long lower limbs, opposable thumbs,
and large brains

______17. Oldest living primate group

______18. Name means humanlike primate

______19. Has flexible hands and feet, eyes that face forward, and
large brains

______20. Small primate that is active at night

______21. Includes all species in human lineage, both modern and
extinct

______22. Examples include lemurs, lorises, and tarsiers

______23. Divided into New World monkeys, Old World monkeys,
and hominoids

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Holt McDougal Biology1The History of Life

Study Guide ASection 6: Primate Evolution