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Evidence of Evolution Make Up #10
Lesson Objectives
Explain how geologic distribution of species relates to their evolutionary history.
Explain how fossils and the fossil record document the descent of modern species fromancient ancestors.
Describe what homologous structures and embryology suggest about the process ofevolutionary change.
Explain how molecular evidence can be used to trace the process of evolution.
Explain the results of the Grants’ investigation of adaptation in Galápagos finches.
Lesson Summary
Biogeography Biogeography is the study of where organisms live now and where they andtheir ancestors lived in the past. Two biogeographical patterns are significant to Darwin’s theory:
The first is a pattern in which closely related species differentiate in slightly differentclimates. The Galápagos tortoises and finches follow this pattern.
The second is a pattern in which very distantly related species develop similarities insimilar environments. The rheas, ostriches, and emus fall into this pattern.
The Age of Earth and Fossils Radioactive dating techniques have confirmed thatEarth is ancient—about 4.5 billion years old. Recent fossil finds document intermediatestages in the evolution of many groups, including whales, birds, and mammals.
Comparing Anatomy and Development Homologous structures are similarstructures shared by related species and that have been inherited from a common ancestor.Similarities and differences among homologous structures help determine how recently twogroups shared a common ancestor. Many homologous structures develop in the same order andin similar patterns during the embryonic stages of related groups. These similarities providefurther evidence that the animals share common ancestors. Body parts that share a commonfunction,
but neither common structure nor common ancestry, are called analogous structures.Analogous structures do not provide evidence for evolutionary descent. Homologous structuresthat are greatly reduced in size or have little to no function are called vestigial structures.
Genetics and Molecular Biology At the molecular level, the universal genetic codeand homologous molecules such as genes and proteins provide evidence of common descent.
For example, similar versions of the homologous protein cytochrome c are found in almost
all living cells, from baker’s yeast to human cells.
Testing Natural Selection Scientists have designed experiments to test natural selection.Peter and Rosemary Grant of Princeton University have spent more than 35 years observingGalápagos finches. The Grants’s observations confirm that competition and environmentalchange drive natural selection.
Biogeography
For Questions 1–3, complete each statement by writing the correct word or words.
1.Biogeographers study where organisms live now and where they and their ______lived in the past.
2.When individuals from a mainland bird population immigrate to various islands, natural selection may result in ______, but different, island species.
3.Distantly related organisms may be similar if they live in ______.
4.What explains the distribution of finch species on the Galápagos Islands?
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5.What explains the existence of similar but unrelated species?
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The Age of Earth and Fossils
6.The illustrations below show organisms whose fossils make up part of the fossil record. The organisms are in order from oldest to most recent. In the boxes, draw an animal that might have been an intermediate form between the shown organisms.
Use the illustrations of the marine organisms on the previous page to answer Questions 7–8.
7.Describe a situation in which organism 3 might have had an advantage over organism 2.
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8.How might these fossils provide evidence for evolution?
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Comparing Anatomy and Development
9.Complete the table about types of anatomical structures.
For Questions 10–14, match the structure with the correct type. A structure type may be used more than once.
Anatomical Structure
_____10.bat wing and mouse arm
_____11.reptile foot and bird foot
_____12.dolphin fin and fish tail
_____13.eyes on a blind cave fish
_____14.snake tongue and dog nose
Use the illustrated homologous structures to answer Questions 15–17.
15.How are the forelimbs similar?
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16.How are the forelimbs different?
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17.How are homologous structures such as forelimbs evidence for common descent?
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18.How does the pattern of embryological development provide further evidence that organisms have descended from a common ancestor?
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Genetics and Molecular Biology
For Questions 19–25, complete each statement by writing the correct word or words.
19.The science of ______provides molecular evidence that supports evolutionary theory.
20.All living cells use ______and ______to code heritable information.
21.In almost all organisms, the universal genetic code ______.
22.Proteins that are ______share extensive structural and chemical similarities.
23.Cytochrome c is a protein used for ______in almost every living cell.
24.Homologous genes called Hox genes control timing and growth in ______.
25.Relatively minor changes in an organism’s genome can produce major changes in an organism’s ______.
Testing Natural Selection
Write the letter of the correct answer on the line at the left.
_____26.Which of the following hypotheses did the Grants test?
A.Differences in beak size and shape produce differences in fitness.
B.For beak size and shape to evolve, the birds must leave the islands.
C.For beak size and shape to evolve, the climate must change radically.
D.Differences in beak size and shape are not determined by genetic mutations.
_____27.The data that the Grants collected proved that there is
A.no link between the environment and the shape of finch feet.
B.no link between the environment and the shape of finch beaks.
C.great variation of heritable traits among Galápagos finches.
D.very little variation of heritable traits among Galápagos finches.
_____28.The Grants conducted their experiment to test which of the followingprocesses?
A.Natural selection
B.Genetic mutation
C.Artificial selection
D.Sexual reproduction
29.The art shows how finch beaks are similar to certain kinds of hand tools. Suppose a finch fed on insects that burrowed into small holes on tree trunks. What type of tool do you think this finch’s beak would resemble? Explain your answer.
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30.Complete the concept map.