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Content Benchmark L.12.D.3
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Life Science
Structure of Life
Organisms and Their Environment
Diversity of Life
Content Areas
Nature of Science (NOS)
Life Science
Earth Science
Physical Science

Students know the fossil record gives evidence for natural selection and its evolutionary consequences. E/S

When teaching all of the L.12.D benchmarks, it is imperative to help students understand the process of science. Most objections and misconceptions about evolution are directly related to the misunderstanding of how science works. When students understand the nature of science, they will understand how scientists have studied the process of evolution. As questions arise about a “supernatural” creation of Earth and the Universe, students who understand the nature of science will understand why supernatural forces cannot be studied as part of scientific processes.

The study of fossils is called paleontology. The study of rocks and land formations is called geology. By combining paleontology and geology, much can be learned about the history of Earth and the history of life on Earth. Fossils are the remains of once living organisms. Most fossils are remains of the hard parts of organisms that are no longer alive (extinct species). The most common types of fossils form when shells, bones, or other parts of organisms are rapidly covered with layers of sediment. As additional sediment is deposited, the organism’s remains become compacted by the additional weight of the new sediment. Water in the soil seeps into the original bones and other solid remains, gradually replacing the original components of the once-living organism with minerals found in the water. Fossil formation occurs over a long periods of time, as the minerals in the organism are gradually dissolved and replaced to form a rock-like material, as spaces in the original organism are filled in with minerals.

To learn more about how different kinds of fossils form, see

Fossils are found in sedimentary rocks. Sedimentary rock forms in layers. In most cases, the lowest layer is the oldest. Successive layers of sedimentary rock contain different groups of fossils. The different types of fossils in the different layers provide evidence that changes have occurred in living things through time. For additional information on the fossil record and how it contributes to our understanding of evolution, see “Evolution and the Fossil Record” found at

For additional information concerning strata, fossils, and geologic structure see Benchmark E.12.C.1

Geologists today are able to establish the relative age of the various layers of the earth’s crust based on their position and the fossils they contain. Both relative and absolute age of various rock layers can be determined using evidence provided in that layer, and the layers found immediately above and below. Fossils and geological formations can be used to provide relative ages of rock layers. For example, if the same type of fossil is found at two locations that are a great distance apart, the fossil provides evidence that the rock layers are probably of a similar age. Figure 1 (below) shows Index Fossils that are used to help establish the relative age of various rock formations.

Figure 1. Diagram of Index Fossils by Geologic Age. For more information as to how fossils are used to determine relative ages of rock layers see

Using radioactive isotope half-life knowledge, absolute age of rocks can be determined (Figure 2)

Figure 2. Diagram of the relative amount of a radio isotope left in a sample
after 3 half-lives.
(From: )

The relative concentration of a radio isotope to its daughter products can be used to help determine the absolute age of the strata, or fossil in question.

For further explanation of radiometric, or absolute dating, see the following sites:, or

It is estimated that our earth is approximately 4.5 billion years old. The first life (prokaryotes) probably appeared about 3500 million years ago (3.5 billion years ago). When the age of the rock layers are known, any fossils found in those layers can be considered the same age as the rock. Thus if a fossil is found in a rock layer that is known to be 100 million years old, then it is known that the fossilized organism lived (and died) about 100 million years ago.

Different types of fossils are found in different aged layers of rock. Therefore, the fossil record supports evolutionary theory by providing evidence that organisms that have lived in the past did change over time. If we examine fossils found in various layers of rock, and look at progressively older layers, we can see that there is a layer below which no human fossils are naturally found. As we progress backward in time, we will eventually see a layer below which no fossils of birds, no mammals, no reptiles, no fish, and eventually, no animal of any kind is found. This is evidence that the kinds of plants and animals, and other organisms have changed over time and is called the Law of Fossil Succession (Figure 3 and 4).

Figure 3 Stratigraphic ranges and origins of some major groups of animals and plants

To learn more about the Law of Fossil Succession, go to

Figure 4. This diagram from the American Geological Institute illustrates
how different fossils have been found in different aged layers of the earth.
The illustration is from

Natural selection is considered a mechanism of evolution. Charles Darwin gathered evidence on many different organisms during voyages in the 1800’s. Careful study and characterization of his data led Darwin to his theory of evolution through natural selection. His theory was based on four premises:

1. Variations exist among individuals within the same species.
2. All organisms produce more offspring that are able to survive.
3. Competition for space, food, other survival needs leads to the elimination of some
organisms of each population.
4. The organisms that have variations which enable them to survive within their
environment and through competition, are the ones most likely to survive and reproduce, thereby passing their characteristics on to their offspring (survival of the fittest, or natural selection).

For more information on Darwin’s theory, go to

Fossils provide evidence that divergent and convergent evolution has occurred. Divergent evolution is when two or more related species become more and more dissimilar to each other. The species involved had a common ancestor, but due to natural selection and adaptations to different environments, the species became increasingly different from each other.

Convergent evolution occurs when two or more unrelated species develop similar characteristics as they adapt to similar environments.

Figure 5. Illustrates convergent evolution of some large vertebrate animals. The shark, ichthyosaur, and porpoise evolved separately, but have similar characteristics which enable them to live in the water and to be efficient predators (from:

To learn more about divergent and convergent evolution see

To learn more about the link between paleontology, geology and evolution, see: The information contained within this web site can be viewed as is, printed as a booklet, or ordered from the Website.

There are gaps in the branches of the fossil records of life. Gaps exist in the fossil record, partly because plants, microorganisms, and soft shelled organisms (majority of marine animals), are not likely to fossilize. Even hard bodied organisms do not frequently fossilize. In addition, changes in the land (erosion, metamorphosis, geological events) can destroy fossils if they were present. However the fossil record does provide significant evidence of evolution and of the history of life on earth.

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Performance Benchmark L.12.D.3

Students know the fossil record gives evidence for natural selection and its evolutionary consequences. E/S

Common Misconceptions associated with this benchmark

1. Students incorrectly believe that individuals adapt to their environment.

Students incorrectly believe that adaptations occur in individuals in response to changes in their environment or the needs of the individual, rather than adaptation occurring on the species level and being changes in a population that accumulate over time. Students think that adaptations and hence, natural selection occurs as an organism changes due to some need, or changes in the environmental conditions, and that this change is then passed to their offspring.

Students have difficulty understanding basic concepts of evolution such as natural selection. They don’t conceptualize that mutations often occur randomly and that some of these random changes are selected for because they help in the survival and reproduction of the organism. Rather, students often believe that new variations occur due to some need, use of a function, or environmental condition, and that once an organism has acquired a characteristic, the change will be passed on to the offspring. This misconception was held by Lamarck in the 1800’s, who concluded that parents can pass acquired characteristics on to their offspring.

To read more about Lamarck, see:

2. Students incorrectly believe evolution through natural selection occurs through variations and changes in DNA that occur naturally and randomly.

If a particular mutation is found in an organism which enables the organism to better survive in its environment, the organism is more likely to live, and to reproduce (survival of the fittest). Because the change that occurred was in the DNA of the organism, that DNA, and therefore the trait, can be passed on to the offspring. Over time, when a significant number of changes have occurred, a new species may develop. Mechanisms of evolutionary change include:

mutation—changes in the DNA of an organism
migration—a group of organisms from a particular species may migrate to a new, geographically isolated area and begin interbreeding among themselves but not with the parent population.
genetic drift—normal variations that occur in the genes of organisms, related to mutations.
natural selection—the organisms most likely to live and reproduce will be the ones that pass on their traits.

More information about evolution through natural selection can be found at:

3. Students incorrectly believe that fossil evidence does NOT support evolution because there are too many “missing links” or missing transitional fossils.

A transitional fossil is one that links a more modern organism with a more primitive organism. A transitional fossil would have characteristics in common with both the primitive organism and the more modern organism. Transitional fossils are often called “missing links.” According to evolutionary theory, however, all organisms are in transition and therefore a specific “missing links” may not actually exist as organisms evolve. In addition there are many organisms that have existed in the past for which no fossils will ever be found, so there will always be gaps in the fossil record. This is because conditions required for fossilization to occur are not always present when on organism dies. Many examples of transitional fossils do exist, providing evidence that species do transition. Several examples are listed below, with links for additional information.

Reptiles to birds:

Terrestrial mammals to whales:

Horse evolution

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Content Benchmark L.12.D.3

Students know the fossil record gives evidence for natural selection and its evolutionary consequences. E/S

Sample Test Questions

1st Item Specification: Recognize patterns of diversity observed throughout geologic history.

Depth of Knowledge Level 1

  1. Species with features between hypothesized ancestors and descendant species are known as
    1. transitional species.
    2. relative species.
    3. homologous species.
    4. middle species.
  1. Which of the following is NOT an example of a fossil?
    1. A frozen wholly mammoth.
    2. The footprints from a dinosaur.
    3. Skin tissue of recently dead animal.
    4. An insect preserved in amber.

Depth of Knowledge Level 2

  1. The following diagram shows the number of marine animal families over the last 600 million years.

Over geologic time, the diversity of marine animal families has

  1. increased over the past 600 million years.
  2. decreased over the past 600 million years.
  3. decreased, but increased with the past 50 million years.
  4. increased, but decreased with the past 50 million years.
  1. Use the diagram below to answer the following question.
(Click Image to Enlarge)


Using the diagram, select the following option that correctly lists the organisms that evolved from the most distant past to the most recent.

  1. Reptiles, Fish, Ginkos, Birds
  2. Humans, Birds, Amphibians, Ferns
  3. Pines, Ginkos, Reptiles, Birds
  4. Fishes, Ferns, Mammals, Flowering Plants

2nd Item Specification: Identify evidence for biological evolution gathered by scientists and others from the fields of biology (including biochemistry and molecular genetics) and geology.

Depth of Knowledge Level 1

  1. George Cuvier reconstructed fossils that showed organisms in the past differed greatly from organisms in the present. His discovery helped support the theory of
    1. catastrophism.
    2. uniformitarianism.
    3. heredity.
    4. evolution.
  1. The fossil record supports the theory of evolution because it shows species
    1. have changed or have gone extinct through time.
    2. that live now are much like those that live millions of years ago.
    3. going through the process of natural selection.
    4. living millions of years ago were identical to species today.
  1. Fossil evidence from the Cambrian period indicates hundreds of new species of animals emerged during that period. These new species arose as a result of
    1. increased volcanic activity.
    2. natural selection and evolution.
    3. extinction and endangerment.
    4. an abundance of food in the world.
  1. Scientists like Charles Darwin hypothesized that the modern day whale evolved from a land mammal, but they had no proof. Eventually fossils were found of a mammal with fins and a vestigial pelvis that was related to the whale. This fossil would be known as a
    1. common fossil.
    2. transitional fossil.
    3. homologous fossil.
    4. coevolved fossil.

Depth of Knowledge Level 2

  1. The diagram below illustrates the evolution of a horse.

This diagram provides evidence for the evolution of a modern horse because it shows

  1. the early ancestors of the modern day horse and when they existed based on fossil evidence.
  2. the early ancestors of the modern day horse as determined by biochemical comparisons.
  3. modern day species related to the horse and the similarities in their bone structure.
  4. modern day species related to the horse and the differences in their molar teeth structure.
  1. The geological theories of James Hutton and Charles Lyell aided Charles Darwin in developing his theory of evolution because it provided evidence that
    1. explained why volcanoes and earthquakes occur.
    2. showed the landforms can change over time through natural events.
    3. suggested the Earth was old enough for evolution to have occurred.
    4. proved the Earth was formed 6,000 years ago.

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Content Benchmark L.12.D.3

Students know the fossil record gives evidence for natural selection and its evolutionary consequences. E/S

Answers to Sample Test Questions

  1. A, DOK Level 1
  2. C, DOK Level 1
  3. A, DOK Level 2
  4. D, DOK Level 2
  5. D, DOK Level 1
  6. A, DOK Level 1
  7. B, DOK Level 1
  8. B, DOK Level 1
  9. A, DOK Level 2
  10. C, DOK Level 2

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Content Benchmark L.12.D.3

Students know the fossil record gives evidence for natural selection and its evolutionary consequences. E/S

Intervention Strategies and Resources
The following list of intervention strategies and resources will facilitate student understanding of this benchmark.

1. The Evolution & the Nature of Science Institutes (ENSI)
ENSI has produced a Website with a multitude of Evolution lessons. The lessons relate to the nature of modern science and evolution. They are appropriate for high school students and most can be modified to meet the needs of a diverse level of students. The lessons can be accessed via

Within this Website, the following activities specifically address fossils and dating layers of rock.
Date a Rock
Who’s on First, a relative dating activity
History of Earth Timeline

2. Activities linking geology, paleontology and evolutionary biology
The following Website developed by the American Geological Institute, is an excellent source of information linking geology, paleontology and evolutionary biology. Several specific pages were indicated in the background information for this standard, but it is well worth the teacher’s time to read thorough all of the pages of this website.

3. Evolution and the fossil record
To help students understand the development of the geologic time scale, to introduce students to the major time periods in earth’s history, and to introduce the role fossils play in helping to understand earth’s history, use:

This site uses a USGS booklet (Internet accessible), and has additional extension activities.

4. Organism by geologic period
The University of California Museum of Paleontology provides a tour of geologic time. Students can click on a specific period of time and learn about the organisms that were alive during that time.

Go to:

5. Evolution activities
Many excellent evolution education modules for many grade levels can be found at Following are specific fossil related activities:

a. The UCMP module, “Life has a History”, sponsored by the NSF, takes the students through a lesson on fossils and biological time. Access this activity at . Students have to answer questions and visit detailed information before moving on to the next stage of the module. Very good basic information is presented on how current observations and the fossil record provide evidence for natural selection. There are two levels, Level one is for K-4 and Level 2 is for grades 5-12. However, Level one might be helpful for ELL students and students with low reading abilities. The teacher’s Guide has handouts and assessments to accompany the activity.

b. Getting into the Fossil Record helps students learn how fossils form

c. Students can visit any geological time period and learn about the rocks, environment, and life that existed during the time period.

6. Fossil Record Adaptation activities
Another set of lessons from the University of California Museum of Paleontology, this series of activities can help students evaluate the importance of fossils to our knowledge of past life, identify conditions necessary for fossilization, understand how organisms are adapted to their environments, and understand the relationships of modern and ancient communities with their environments.

7. Human Evolution Activities
For an activity on human evolution, Building Bodies is an online interactive lesson that demonstrates how bipedalism in humans developed as a series of adaptations over time.

8. Additional Evolution information
For additional information on what is recommended in evolution education, see: Evolution on the Front Line: An Abbreviated Guide for Teaching Evolution from Project 2061 at AAAS at:

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