First Name
Change Over Time
Last Name
State Standard:
H.2L.4 (b, e) -- Explain how biological evolution is the
consequence of the interactions of genetic variation, reproduction and inheritance,
natural selection and time.
10
8
6
4
1
Response
Exceeds
(excellent)
Meets
(proficient)
Nearly Meets
Scoring Rubric
Evaluate the impact of the interactions of genetic variation, reproduction and inheritance, natural
selection and time on biological evolution (change)
Explain how biological evolution is the consequence of the interactions of genetic variation, reproduction
and inheritance, natural selection, and time, using multiple lines of scientific evidence.
Describe the process of biological evolution through natural selection
Does Not Meet
Recognize that species have changed over time
Did not participate
Incomplete
Score
Peppered Moths
In some organisms that have a short life cycle, biologists
have observed changes in a population due to rapid environmental
fluctuations. In the 1950's, English biologist H.B. Kettlewell studied
camouflage adaptations in a population of light and dark colored
peppered moths, Biston betularia. The moths rested on the trunks
of trees that grew in both the country and the city. Moths are
usually speckled gray-brown, or dark moths (which occur occasionally
as black moths). Birds pluck the moths from the trees for food. Urban industrial pollution had
blackened the bark of the city trees with soot. In the photo, you see a city tree with dark bark similar
to the color of one of the moths.
Part A
Background: Kettle well raised more than 3000 caterpillars to provide adult moths. He marked the
wings of the moths these caterpillars produced so he would recapture only his moths. In a series of
trials in the country and the city, he released and recaptured the moths. The number of moths
recaptured in a trial indicates how well the moths survived in the environment. Examine the table below
and calculate the recapture rate percentages.
Location
Country
City
Released
Recaptured
Recapture rates
Released
Recaptured
Recapture rates
# of light moths
496
62
62/496 =
137
%
18
18/137 =
# of dark moths
488
34
34/488 =
493
%
136
%
136/493 =
%
Analysis:
1. Explain the differences in the in survival rates in the country and the city moths in terms of
natural selection.
2. Some scientists would argue that the populations of peppered moths are evolving based on
adaptations to the environmental changes. They would argue that given enough time these
ancestral species would evolve into an array of species to fit a number of diverse habitats. This
is called ___________________ radiation.
Procedure:
Part B Simulation
1. Place a sheet of white paper on the table and have one person spread 30 white circles and 30
newspaper circles over the surface while the other person isn't looking.
2. The "predator" will then use forceps to pick up as many of the circles as he can in 15 seconds.
3. The number that are left are doubled to represent the next generation.
4. This trial will be repeated with white circles on a newspaper background, newspaper circles on a white
background, and newspaper circles on a newspaper background. Record the data in the table.
Generation
1
2
3
4
5
Generation
1
2
3
4
5
Starting Population
Newspaper
30
Populations Start on White Background
Final Populations (how many of the original were left)
Double these
White
Newspaper
White
final numbers to
30
get your starting
populations for
the next
generation
Populations Start on Newspaper Background
Starting Population
Final Populations (how many of the original were left)
Double these
Newspaper
White
Newspaper
White
final numbers to
30
30
get your starting
populations for
the next
generation
Analysis:
1. Describe how the population of moths changed in each generation for both the newspaper
and white moths.
2. What moth coloration is the best adapted for a dark (newspaper)
background? ______________________________
3. How does the simulation model natural selection?
4. Plot the data in the table below. Plot Year
years on the x-axis and the number of
moths on the y-axis. You should have 2
2
3
lines on your graph.
4
5. Suppose two Brazilian species of
5
6
butterflies with light or dark
7
colorations showed similar growth rates
8
as England's moths . Biologists would
9
10
consider this ___________________
evolution. (Hint: divergent or convergent)
# light
moths
Captured
537
484
392
246
225
193
147
84
56
# dark
moths
Captured
112
198
210
281
337
412
503
550
599
#
Years