Evidence for Evolution
True or False
Name___________________ Class______________ Date________
Write true if the statement is true or false if the statement is false.
1. ________ Evidence for evolution includes millions of fossils.
2. ________ Fossils generally form from the hard parts of organisms.
3. ________ It is very common for dead organisms to become fossils.
4. ________ Remains are less likely to become fossils if they are covered quickly by sediments.
5. ________ Some fossils form when dead organisms are frozen in glaciers.
6. ________ Relative dating can be used to determine how long ago a fossil organism lived.
7. ________ Fossil evidence shows that whales evolved from mammals that had always lived in the
ocean.
Critical Reading
Read this passage based on the text and answer the questions that follow.
Scientists have learned a lot about evolution by comparing living organisms. They have compared
body parts, embryos, and molecules such as DNA and proteins.
Comparing body parts of different species may reveal evidence for evolution. For example,
mammals may have front limbs that look quite different and are used for different purposes. Bats
use their front limbs to fly, whales use them to swim, and cats use them to run and climb. However,
the front limbs of all three animals—as well as humans—have the same basic bone structure. The
similar bones provide evidence that all four animals evolved from a common ancestor.
An embryo is an organism in a very early stage of development. Embryos of different species may
look quite similar, even when the adult forms look very different. For example, the embryos of
chickens, turtles, pigs, and human beings look so similar that it is hard to tell them apart. Such
similarities provide evidence that all four types of animals are related. They help document that
evolution has occurred.
Scientists can compare the DNA or proteins of different species. If the molecules are similar, this
shows that the species are related. The more similar the molecules are, the closer the relationship is
likely to be. When molecules are used in this way, they are called molecular clocks. This method
assumes that random mutations occur at a constant rate for a given protein or segment of DNA.
Over time, the mutations add up. The longer the amount of time since two species diverged, the
more differences there will be in their DNA or proteins.
Questions
1. Explainhowthefrontlimbsofdifferenttypesofmammalsprovideevidencethattheyevolvedfrom
acommon ancestor.
2. How does a comparison of animal embryos provide evidence for evolution?
3. 3. The longer the amount of time since two species diverged, the more differences there will
be in their DNA. Explain why.
Multiple Choice
Highlight the letter of the correct choice.
1. Most of what we know about dinosaurs is based on
a. molecular data
b. similarities in embryos c. vestigial organs
d. fossils
2. Which of the following parts of animals are most likely to be preserved as fossils?
a. skin
b. feathers c. hair
d. teeth
3. The front limbs of whales, bats, and cats
a. look very different
b. are used for different purposes
c. have the same basic bone structure d. all of the above
4. The use of molecular clocks assumes that
a. more similar molecules reflect closer relationships
b. mutations occur at an increasing rate for a given molecule c. most molecules are identical in all
living species
d. all of the above
5. The Grants observed an increase in the average size of finch beaks during a
a. drought
b. hurricane
c. cold spell
d. volcanic eruption
6. Fossils most often form when minerals in water turn the remains of organisms to
a. vestigial structures
b. sediments
c. bones
d. stones
7. What percent of chimpanzee DNA is the same as human DNA?
a. 24.4 b. 44.4 c. 88.8 d. 98.8
Matching
Name___________________ Class______________ Date________
Match each definition with the correct term.
Definitions
1. ________ any method of estimating the age of fossils that determines only which of two fossils
is older or younger than the other
2. ________ any evidence other than organic remains that a living organism leaves behind
3. ________moleculethatiscomparedamongspeciestoestimatehowlongithasbeensincetheydiverg
edfrom
a common ancestor
4. ________ hardened tree resin
5. ________ body part that is no longer used but is still present in modern organisms
6. ________ any method of estimating the age of fossils that provides an approximate age in
years
7. ________ very early stage of development of an organism
Terms
a. amber
b. molecular clock c. relative dating
d. embryo
e. trace
f. absolute dating
g. vestigial structure
Fill in the Blank: use the most appropriate terms (some may be found within the
worksheet some may not)
Name___________________ Class______________ Date________
Fill in the blank with the appropriate term.
1. _________________ are the preserved remains or traces of organisms that lived during earlier
ages.
2. Relative dating is based on the _________________ of fossils in rock layers.
3. Carbon-14 dating is a method of _________________dating.
4. A scientist who studies fossils to learn about evolution is called a(n) __________________.
5. Fossils found in lower rock layers are generally_________________than fossils found in rock
layers closer to the surface.
6. The human appendix is an example of a(n)_________________ structure.
7. In the 1970s, Peter and Rosemary _________________ documented evolution by natural
selection taking place on the Galá pagos Islands.
Critical Writing
Name___________________ Class______________ Date________
Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete
sentences.
Explain how fossils form.