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Natural Selection Study Guide/Answer Key
1. A characteristic that improves an organism’s ability to survive is an
adaptation_. Over time, this may be an animal’s response to changes in the
environment.
2. The process by which populations slowly change over time is called
__Evolution .
3. A characteristic that can be passed from parent to offspring through
genes is called a trait_.
4. Charles Darwin’s theory of natural selection was based partly on his
observation that some organisms have more variations in traits than others
do.
5. Why does a spider overproduce hundreds of eggs? To ensure the survival
of their species. Many eggs means that at least a couple will grow to
adulthood and reproduce
6. Why can insect species adapt very quickly to insecticides? Since the
reproduction speed of insects is much higher than ours, they can more easily
pass on the toxin-resistant genes and become immune to the effects of
pesticides.
7. What are 4 things that populations of all species are influenced by?
Overproduction
Competition
Variations
Selection
8. The fact that an organism’s offspring are not identical (they are
different from each other) is known as _Variations. This is necessary for
natural selection to occur in a species.
9. Minerals seeping into an organism’s remains form _fossils, which are
preserved remains most commonly found in sedimentary rock.
Natural Selection Study Guide/Answer Key
10. When scientists study fossils in layers of sedimentary rock, which rock
layer will contain fossils that most closely resemble present-day organisms?
Top layer
11. Scientists compare organisms’ DNA to support the theory that all species
share a common ancestor. (similar traits and similar DNA means they are
more closely related)
12. Shrubs growing longer thorns over many generations is an example of
evolution.
13. What process often begins by a portion of a population becoming
physically or geographically separated? speciation (by geographic isolation)
14. A population of organisms is separated into two groups for many years.
When will the two populations be considered two different species? When
they can no longer reproduce together.
15. Darwin theorized that individuals having an advantage due to their traits
or abilities would be more likely to survive and reproduce. His theory is
known as _Natural Selection.
16. When certain genes make organisms more likely to survive and
reproduce, which process can occur? The adaptation would allow for
Evolution to occur through natural selection
17. Which of the following are examples of natural selection: * them.
*Elephants passing the tusk less trait to offspring
*Male birds developing extremely colorful displays of feathers
*Insects developing pesticide resistance
Dog owners breeding their pets to produce friendlier offspring
18. What is the process by which organisms that are better adapted to
their environment survive and reproduce more successfully than less welladapted organisms do? Natural Selection
Natural Selection Study Guide/Answer Key
19. Darwin noticed that finches on different islands of the Galapagos Islands
were similar but their beaks differed. What explanation for these
differences did he propose? The South American finches migrated to the
Galapagos and Natural Selection occurred, and eventually evolution.
20. What process would farmers use to produce vegetables that will grow in
a specific climate? Selective Breeding
21. What evidence of natural selection is available today that was not
available to Darwin? Knowledge of genetics
22. Farmers allowing only sheep that produce the best wool to breed is an
example of Selective Breeding
23. Define the following terms:
a.
Fossil record- A record of fossils found and put into sequence
b. Speciation-The formation of a new species as a result of evolution
c. Extinct- A species that no longer exist
d. Extant- A species that is still living
e. Scientific Theory- Scientific Theory is a well-tested concept that
explains a wide range of observations.
f. Selective Breeding- Process in which humans select and breed for
desired traits
25. What sources helped Charles Darwin develop his ideas for evolution?
Characteristics he observed of Galapagos animals
Knowledge of Selective Breeding
Observations of the South American Finches