Transcript Selection and Adaptation Inquiry Station Answer Key


Define fitness
Ability to survive and reproduce

Define adaptation
Any characteristic that increases fitness

Describe how the population of mice is different in figure 3
compared to figure 1. Explain what happened to cause this
difference.
#3 has more gray mice than white
White mice were more noticeable so they got eaten by predators
The white mice were also slower.

For the mice in the figure, what characteristic was an
adaptation that increased fitness?
P
A
R
T
They blended with the background and produced more offspring.

From an evolutionary point of view, which mouse in the chart
would be the fittest? How do you know that this mouse would
be the fittest? Use data from the chart to support your
response.
Gray mice b/c they camouflaged well and it
reproduced the most
1
Define heritable trait. A characteristic which is influenced by genes
and passed from parents to offspring
Define adaptive heritable trait.
A heritable trait that increases fitness
Explain why the percent of mice with gray fur would increase from generation to
generation
They camouflaged with their background.
Notice that population size increased from 6 mice in generation 1 to 28 mice in
generation 2. Suppose that this population of mice lived on a small area of gray
sand that only had enough food for ~30 mice and white, gray and black mice were
equally good at competing for food. What do you think would happen to the
numbers of white, gray and black mice in generation 3? Explain your reasoning.
Generation 3 would have more kids, resulting in less food.
Some mice will die off because of this and only the fittest will survive.
A population of mostly gray mice living on a patch of gray sand are asleep in their
burrows. While the mice are sleeping, the gray sand is replaced by white sand.
(Perhaps the owner of the desert has a plan to attract more tourists.) Think about
what would happen to the population of mice on the white sand. After several
White
generations, most of the mice would have _____________
fur. (white/gray/black)
P
A
R
T
2
Explain how the change in the color of the sand could
result in a change in the most common fur color in this
population of mice.
Which ever color is able to blend in with the background
will survive; while the others will be more noticeable
and be eaten by predators.
When mice live on gray sand, which color fur is an
Gray fur
adaptive heritable trait? ______________________
When mice live on white sand, which color fur is an
White fur
adaptive heritable trait?______________________
Is the same trait adaptive in both environments?
Yes, because in both environments the fur color is adaptable
___________________________________________
P
A
R
T
2

Define Natural Selection
The adaptive heritable trait tends to become more
common in the population

Why did the deer choose the cactus without spines?
It could eat the flowers with ease.

What adaptive heritable trait preserved the cactus?
The spines
P
A
R
T
3

Researchers have found differences in mortality for the
speckled and black forms of the peppered moth in
different types of environment.

Which form of the peppered moth do you think had higher
mortality in forests in unpolluted areas where tree trunks
and branches are lighter? ___black
___ speckled
✓


Which form of the peppered moth do you think had higher
mortality in forests in areas where air pollution had
resulted in dark tree trunks and branches?
___ black
___ speckled
Explain your reasoning.
✓
Depending on the background, some
colors blend better
P
A
R
T
4

Looking at the Punnett squares identify the percentage of
peppered moth offspring when:
100% speckled
 Both parents are homogeneous recessive __________
0% speckled
 Both parents are homogeneous dominant __________
75% black
 There are two heterozygous parents _________
25% speckled
B=Black
b=speckled

Based on these Punnett squares, explain why peppered moths
generally have offspring that look like their parents.
P
A
R
T
The peppered moths have the parents genes.
4

Which trait was an adaptive heritable trait for peppered moths
in industrialized areas with dark tree trunks and branches?
___ black form
___ speckled form
✓

Which trait is an adaptive heritable trait for peppered moths in
unpolluted areas with lighter tree trunks and branches?
___ black form
___ speckled form
✓


Many people think of the process of evolution as "survival of the
fittest". How do you think most people interpret "survival of the
fittest"? The organisms with the most favorable traits
are able to survive for long periods of time and
reproduce  passing along their traits
Use the peppered moth example to illustrate the following
generalization: Natural selection acts on individuals, but only
populations evolve.
The variation amongst species allows specific
individuals to survive and reproduce, but over
many years the whole population can evolve.
P
A
R
T
5