Biology 11
Name_______________
Evolution Review
1. Explain the 2 basic assumptions Lamarck used to explain his Theory of
Acquired Characteristics.
The law of use and disuse and the law of Inheritance of acquired characterisitics
2. Give an example of how Lamarck thought evolution may have occurred.
The ancestors of the modern long necked giraffe had short necks. In order to feed
on the leaves of tall trees, the giraffes had to stretch their necks. This continual
stretching caused their necks to become longer. This trait was passed on to the
following generations of giraffes. Each successive generation had a slightly longer
neck than the previous generation. Over many generations, the giraffes evolved
to having long necks
3. Give the significance of the following to Natural selection:
a. Genetic Variation – varys their physical attributes and their
capabilities, giving the environment something to select between.
b. Over reproduction- therefore more offspring are produced than are
required to maintain the existing population, which creates
competition.
c. Competition- due to limited resources there is competition which
allows for the strong to survive and reproduce
d. Environment- selects out those individuals which are unfit before
they can successfully reproduce
e. Mutations- allow for new traits necessary for large evolutionary
changes such as a new species.
4. Give a possible Example of Evolution of the white snow bunnies, using the
theory of Natural Selection. (use point form numbered 1-7)
a)
b)
c)
d)
e)
f)
Variation (brown and white bunnies)
Over-reproduction and competition
Weak- do not reproduce
Strong- reproduce
Each generation more strong (in this case more white bunnies)
Over many generations, evolution has occurred.
5. DNA stands for __deoxyribonucleic acid
6. Draw a DNA nucleotide (only 1)
7. Describe the full structure of DNA.
(include backbone, bonds, base pairing)
8. What are the 3 roles of DNA in Evolution
a) Responsible for inheritable traits
b) Variation through recombination
c) New traits through mutations
9. Why is variation created by sexual reproduction NOT sufficient to allow
one species to evolve into another (speciation)?
Variation by sexual reproduction only creates new combination of genes/traits,
not NEW traits- New traits acquired through mutations are required to evolve to a
new species
10. What is the difference between a chromosome, gene and allele?
Chromosome- long strand of DNA, consisting of many genes
Gene- a segment of DNA, which determines a particular trait in an
organism.
Allele- Different forms of a particular gene
11. Looking at the frequency of the tallness allele from one generation to the
next, has evolution occurred in either of the two populations?
Generation 1
Generation 2
Population A
f(T)= 0.3
f(T)=0.5
f(t)=0.7
f(t) =0.5
Population B
f(T)= 0.6
f(t)=0.4
f(T)=0.6
f(t) =0.4
Pop A- yes evolution has occurred because the frequencies have
changed from one generation to the next.
Pop B- No, the frequencies in both generations are the same.
12.
Explain the 4 mechanisms that can result in Microevolution
Mechanism
Description
Example
Environment selects
for one trait and
against another.
Natural Selection
Mutation creates new
traits
Mutation
Differential
Migration
Genetic Drift
Emigration of a
number of
individuals with a
given gene will
decrease the
frequency of that
allele in the
remaining pop.
Disasters such as
floods, fires, earth
quakes
13.
Modes of Natural Selection:
Environment
Stabilizing
Stable
Directional
changing
Disruptive
changing
Selected against
extremes
One extreme
average
Selected for
average
Both extremes
Outcome
Mostly average
(brown)
The other
extreme
Mostly grey or
white
Half white and
half grey
Draw the new
graph
14.
What type of selection is occurring in the example of the peppered
moth?
Directional
15.
Define and give examples of analogous structures and homologous
structures
Define
Analogous
Similar in function, but
different in structure
Homologous
Similar in structure, but different
in function
Bird wings, insect wings
Whale flipper, human arm, bird
wing, horse foreleg
Examples
16.
Give the role of each of following in Speciation:
a. Geographic Isolation- environmental separation causes a stop in
gene flow
b. Different Environments- different selective pressures
c. Divergence- become better adapted to their respective environments
d. Reproductive Isolation- not able to interbreed
17.
Convergence can lead to Ecological Equivalents, describe this
process.
Two species living in similar environments will face similar selective pressures
which will cause them to become more alike.
18.Compare and Contrast Punctuated Equilibrium with Gradualism
Similarities
Differences
Both involve the environment
G-small changes
Natural Selection occurs in both
PE- large changes
Evolution occurs in both.
G- slow
PE-rapid
G-continous
PE-not continuous
G-transitional forms
PE- no transitional forms
19. Evidence for Evolution
Direct Evidence
Fossil Evidence
Recent changes in Inheritable
Characteristics Observed in a
Population
Indirect Evidence
Evidence from Comparative
Anatomy
Evidence from Comparative
Embryology
Evidence from Comparative
Biochemistry