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Evolution Study Guide
1. Name three men whose ideas contributed to Darwin’s theory (other than Darwin), and tell what they had
to say.
Lamarck- species change over time
Malthus- the number of people in the human population increases faster than the food supply
Wallace – proposed a theory a lot like Darwin’s theory of natural selection
2. What specifically, did Darwin observe on the Galapagos islands that led him to develop the theory of
natural selection?
Different species of birds were very similar to each other and to mainland birds, but they were each adapted
to use a different food source and live in differing environmental conditions
3. State the four points of Darwin’s Theory.
a. Variations exist in a population
b. The best adapted to an environment survive.
c. They reproduce and pass on their genes
d. The fossil record supports this idea.
4. Define:
a. natural selection- the environment “decides” which individuals in a population are best
adapted to it because they will survival & successfully reproduce
b. adaptation- any change in physical appearance or behavior that helps the members of a
population to survive
c. speciation- formation of a new species from an existing one
d. reproductive isolation- when members of two different species cannot or will not breed together.
e. paleontologist- one who studies fossils
5. Contrast gradualism with punctuated equilibrium.
Gradualism- a slow change in a population over time
Punctuated equilibrium- a long period of no changes in a population followed by a period of rapid
change, producing new species (usually due to a severe change in the environment)
6. In what way did Darwin’s finches vary from each other? What did Darwin think was the cause of the
variations? The birds vary in color and patterns in their feathers and in the type and size of their beaks.
Darwin thought this was due to where they lived, but especially to what they ate.
7. What is a nonrandom mating type selection?
Inbreeding- choosing a mate from the local population, happens when a population is isolated
Outbreeding- deliberately choosing a mate from a nonlocal population
Choosing a mate for some “desirable” characteristic in the possible mate instead of randomly.
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8. Define:
a. Species- all the members of a population that can successfully interbreed with each other
b. Gene pool- all the genes of all the members of a population
c. Speciation- species formation
9. Differentiate between allopatric and sympatric speciation.
Sympatric speciation- species develop from as original type without geographic isolation
Allopatric speciation- New species develop because a small population is isolated
10. Why is sexual reproduction needed for most forms of evolution?
Because it provides a lot of genetic variation & new combinations of genes
11. How can we use similarities in DNA to study relatedness between organisms?
The more similarities there are in the DNA and protein sequences, the more closely related two species
are and the more recently they shared a common ancestor.
12. What is artificial Selection?
Artificial selection is choosing crops or farm animals fro breeding because they have traits that we like
and want to make stronger (amplify).
13. What does the theory of natural selection say? Best adapted to an environment will survive & reproduce
14. What is the idea behind cumulative natural selection? selection (several selections as traits changed and
mutations arose)? Is this a rapid or slow change?
The changes in a species add up over time and will change a population enough to make a new species.
This is a slow process.
15. Put protein, RNA, and DNA in a list from first formed to last formed.
It is thought that RNA formed first, then DNA, finally protein evolved.
In the cell’s protein making process, however, DNA forms, then RNA, then protein.
16. What molecules made it possible to pass on genetic traits? The nucleic acids, DNA & RNA
17. What are fossils? What do they show? Name at least two ways in which fossils form.
a) Preserved remain of organisms that lived long ago.
b) They show the order in which species seem to have evolved
Fossils form by
c) mineralization- when hard body parts are replaced slowly by minerals,
d) preservation- when parts or all of the body is frozen or preserved in a bog, or by
e) cast & mold- when a mold is made of a body which rots, leaving the mold behind; later the mold
fills with silt or sand making a cast of the body.
18. Define:
a. extinction- all members of a species die
b. mass extinction- all members of several different species die
19. To support evolution and to understand the relatedness of species, comparisons are made between two
types of chemicals. Which two chemicals are these? DNA & protein.
20. What is a vestigial structure? A structure that was larger in an ancestral type than it is in something
alive, now. Vestigial structures were used more often in the ancestor.
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21. Differentiate between a homologous structure and an analogous structure.
Homologous structures have a similar organization because the species in which they are found have
common ancestors.
Analogous structures have the same function and possibly a similar structuree, but that is because there is
a common need To fly, for example)
22. What are the five factors that are necessary for natural selection to occur?
a. small population & isolation
b. gene flow- ( loss of genes as some types die out; gain of new genes from mutation)
c. non-random mating- including inbreeding
d. natural selection- environment may be different & changing
e. mutations
23. What is a Hardy Weinburg equilibrium? What five things does a population have to have to be stable?
Hardy Weinburg equilibrium is when the gene frequency for all genes in a population does not change.
a. Large population size
d. The population is isolated from other populations
b. No mutations
e. No gene flow
c. Random mating
f. No natural selection
24. What are the five factors that are necessary for natural selection to occur?
a. Natural selection
d. isolation
b. Nonrandom mating
e. Mutations
c. Gene flow
f. Small population size
25. Define:
a. sympatric speciation- a new species arises with in an existing population ex- they start eating
different food.
b. allopatric speciation- a new species areises because a small population gets separated from the main
group and genetic drift, mutation and adaptations eventually change it into a new species
c. adaptive radiation- one species gives rise to several others as some members of the species adapt to
different niches- things to eat, places to live, etc
d. stabilizing evolution- natural selection favors the “average members “ of a population; there is little
change in the members of that population
e. disruptive evolution- Natural selection favors the more “extreme” phenotypes in a population. Te
average types die out, & the species changes into two new species.
f. directional evolution- Natural selection favors only one of the “extreme forms of an individual or
extreme forms adapted to a specific environment
26. How do germs become resistant to antibiotics? What is another example of this?
Germs become resistant when they are exposed to small or doses of antibiotics, or when antibiotics
aren’t taken on schedule or are not completed by the patient. The resistant bacteria survive and reproduce.
The next generation of bacteria will be resistant to the antibiotic. This also happens with bugs & pesticides
27. What are camouflage and mimicry?
Camouflage- when an organism looks like its surroundings
Mimicry- when an organism looks like a dangerous or undesirable animal to fool predators
28. What are genotype and phenotype?
a. Genotype- the alleles in the gene pair (AA or Aa or aa)
b. Phenotype- the physical appearance of an organism, its traits
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29. Define:
a. Allelic frequency- how frequently an allele of a gene ( a particular form of a gene) occurs in the gene
pool of a population
b. Genetic drift- A change it the frequency of a gene or genes
c. Polyploidy- when organisms have more than 2 sets of chromosomes
d. Gene pool- all the genes of all the members of a population
e. Selection- when having a particular trait or set of traits makes an individual more (or less) capable of
surviving in its environment
30. What are two main focuses of natural selection? Survival & reproduction