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Darwinian Evolution Study Guide
1. A species of flower lives in an environment that has always had an abundance of rain but
is now experiencing less rainfall each year.
Name a variation within the flower population that would be beneficial in terms of
natural selection.
Longer roots to reach more water
Waxy leaves to hold water in
2. A species of newt produces a toxin that can kill predators. Scientists have observed that
some garter snakes can feed on the newts because they have a natural resistance to the
toxin.
In areas where populations of newts and garter snakes interact, what predictions can be
made about how the two species will evolve?
Garter snakes will probably evolve to be more and more toxin resistant.
Newts will probably evolve to not produce the toxin any more, since it is not effective it is
wasted energy.
3. Define antibiotic resistance, and give an example.
Antibiotic resistance is when a population of bacteria evolve so that a particular
antibiotic no longer kills them. An example is penicillin resistant bacteria.
4. Define biological evolution.
The change in the allele frequencies in a population over time.
5. Define survival of the fittest, and give an example.
The organisms best suited for a particular environment survive to reproduce and pass on
their genes for the beneficial trait(s).
Antelopes with strong legs are able to run faster and therefore escape their predators
better. They reproduce and make babies with stronger legs. Over time, the population of
antelopes evolves very strong legs to be able to outrun lions.
6. Give an example of a beneficial and a harmful mutation.
Beneficial – virus resistance, antibiotic resistance, pesticide resistance
Harmful – cystic fibrosis, sickle cell anemia
7. Give an example of Lamarck’s theory of evolution.
Giraffes who stretch their necks out pass down that acquired trait to their children.
Blacksmiths who build up their arm muscles pass down that acquired trait to their
children.
8. How did the different species of finches in the Galapagos Islands evolve? (How did one
common ancestor “turn into” all of the different types?)
A single type of finch migrated from the mainland, but each island’s unique environment
caused the finches to evolve independently to be best suited for their particular
environment.
9. How do variations within a population effect natural selection?
Variations provide the diversity necessary for evolution to happen. When everything is
different, some differences are “good” and some are “bad.”
10. How old is the earth?
4.6 billion years
11. The smooth-skinned, leaf-tailed gecko lives on Madagascar, an island off the coast of
Africa. The gecko hunts at night and sleeps on trees by day. The color and pattern of the
gecko’s body resembles leaves. How would Darwin describe the evolution of body
color?
All geckos are different. The ones who look more like leaves were less likely to be eaten.
They survived to pass on their coloring to their offspring. Over time, the population of
geckos evolved to resemble leaves more and more.
12. What is the source of genetic variation within a species?
DNA mutations
13. What question did both Lamarck and Darwin try to answer with their theories of
evolution?
What causes populations of organisms to change over time?
14. Why are polar bears white (evolutionarily speaking)?
Their white fur camouflages them so they are better able to sneak up on prey.
15. Modern evolution theory includes three concepts: natural selection, environment
pressure, and DNA mutation.
a. Identify and explain why each supports the theory of evolution.
Natural selection – survival of the fittest. The organisms best suited to a particular
environment are more likely to survive and pass on their beneficial traits.
Environment pressure – The environment determines which mutations are beneficial.
DNA mutation is the source of genetic variation that makes some organisms better suited
to their environment than others.
16. According to one evolutionary theory, insect species such as bees increased dramatically
after the emergence of flowering plants. This may have led to an increase in the
adaptations of the insects and the plants.
a. Describe one reason why the number of insect species may have increased when
flowering plants appeared.
There was more food available.
b. Describe another reason why the number of insect species may have increased
when flowering plants appeared.
As more plants evolved, more niches opened up, and more insects evolved to fill
those niches.
c. Describe one adaptation that plant species may have developed in response to the
increase in insect species.
Plants might have developed colors or smells to attract insects to them to help
them pollinate.
d. Describe another adaptation that plant species may have developed in response to
the increase in insect species.
Plants might have developed poisons or spines to prevent insects form eating
them.