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Name:_______________________________
Period: ______
Evolution Review Homework
/20
Directions: Write the best answer to each question on the line provided
_______1. The difference in the physical traits of an individual from those of other individuals
in a group is called a(n):
A. change
B. adaptation
C. species
D. variation
_______2. Mutations are important because they bring about
A. death of an organism in which they develop
B. decreases ability for an organism to mate
C. genetic variation needed for a population to evolve
D. immigration of a population to a new location
_______3. What is the term for a feature that allows an organism to survive better in its
environment?
A. variation
C. adaptation
B. homologous structures
D. vestigial structures
_______4. Over time, adaptations can help populations survive through
A. environmental changes
C. allele changes
B. genetic changes
D. mutation changes
_______5. Which of the following describes natural selection?
A. it acts on the weather
B. it selects for existing physical traits
C. it forms new traits that the organisms asks for
D. it forms new genetic material that the species needs
_______6. The more genetic variation a population has, the more likely it is that some
individuals will:
A. die
B. migrate
C. survive
D. mutate
_______7. Which of the following is an example of a vestigial structure?
A. wings of a bald eagle
B. hind legs of a cat
C. gills of a trout
D. pelvic bone of a snake
_______8. The wings of robins and the wings of dragonflies are examples of
A. vestigial structure
B. analogous structure
C. homologous structure
D. fossil structure
_______9. Fossil evidence shows that structures considered vestigial in living organisms
A. are not found in ancient organisms
B. have always been vestigial
C. were useful to their ancestors
D. do not fill gaps in the fossil records
_______10. Some organisms that share a common ancestor have features that have different
functions, but similar structures. These are known as:
A. vestigial structure
B. analogous structure
C. homologous structure
D. fossil structure
_______11. Proteins sequences in one organism that resemble those of another suggest a:
A. coincidence
B. lack of evolutionary relationship
C. great number of mutations
D. shared ancestry between the organisms
_______12. We identify organisms as belonging to the same species if they are capable of:
A. inhabiting similar habitats
B. having the same life expectancies
C. producing fertile offspring
D. evolving comparable adaptations
_______13. What is speciation?
A. combining of two species to form one with different traits
B. isolation that affects mating behavior
C. timing of mating that prevents normal sexual selection
D. two or more species that evolve from an existing one
_______14 Black bears, grizzly bears, and polar bears are species that came from one common
ancestor. This is an example of
A. geographic isolation
B. adaptive radiation
C. analogous structures
D. genetic isolation
Adaptive radiation is the process by which many new species of organisms evolve from a
common ancestor. The new species evolve and fill different environmental niches where there is
less competition. A niche is the role an organism plays in a particular environment. A niche
includes an organism’s feeding habits, where it lives, how it reproduces, and other life activities.
Organisms move into new niches in the environment though chance mutations that have positive
adaptive value. A positive adaptation would be one that allows an organism to live successfully
in a new niche. If there is little competition in the niche, the organism has a better chance to
survive and reproduce.
During his travels to the Galapagos Islands, a group of islands that are isolated from the
mainland of South America, Darwin saw many different and unusual animal species. One of the
populations he observed was a finch (a small bird) population. He wrote that there were 13
different finch species living on the islands. He noticed that their beak shapes were very
different. The beak differences allowed the birds to live in different niches based on the type of
food they ate. Darwin thought the finches had evolved from one common ancestor. Darwin did
not know why birds with beaks different from their parents were produced. He guessed that the
new beaks gave finches new feeding niches where there was less competition for food. For
example, he saw a large ground finch with a blunt, powerful beak for breaking open hard seeds.
Because it could eat bigger seeds than other ground finches, it was not in direct competition with
smaller birds. Therefore, the smaller birds could successfully inhabit one niche and the large
birds inhabited another niche. Over time, other mutations occurred and eventually many different
finch species were produced.
15. What is a niche?
16. Describe what Darwin saw with the finches.
In Modern times there have been many opportunities for scientists to observe evolution in
progress. For example, in some areas, such as the Adirondack Mountains in New York State,
DDT was sprayed to kill a black fly insect pest. DDT is an insecticide, a chemical that kills
insects. After a few sprayings, most of the black flies disappeared, but some black flies had
genes that made them resistant to DDT. When the environment changed (was sprayed with
DDT), the DDT-resistant gene suddenly had positive survival value. Since most of the black flies
had been killed, there was little competition for food. The resistant genes rapidly increased in
numbers. Within a couple of years, the DDT-resistant black flies had reproduced in such large
numbers, that they were again pests to the inhabitants of the Adirondacks. (DDT spraying has
since been banned in New York State and a black fly population with no resistance to DDT is
reappearing).
Another organism that evolved during modern times is the Staphyloccocus bacteria.
When the antibiotic was first used, some Staphyloccocus bacteria had genes that made them
resistant to antibiotics. When the use of antibiotics became widespread, these genes increased in
numbers producing a population of bacteria that was not killed by antibiotics. Even today,
scientists continuously develop new antibiotics because the bacteria population mutates and
produces new antibiotic-resistant strains. Mutations are not caused by environmental change.
Mutation s occur randomly. Mutations with positive survival value allow organisms to be
better adapted to their environment. The environment selects those variations, or adaptations,
that may have survival value.
17. Why didn’t all of the black flies initially die?
18. What happened after a couple of years?
19. Why do scientists continually need to develop new antibiotics?
20. How do mutations occur and why are mutations important?