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Chapter 16 ~
Vocabulary
Behavioral Isolation
Directional Selection
Disruptive Selection
Founder Effect
Gene Pool
Genetic Drift
Genetic Equilibrium
Geographic Isolation
Hardy – Weinberg
principle
Definition
Picture
Vocabulary
Polygenic Trait
Relative Frequency
Reproductive Isolation
Single – Gene Trait
Speciation
Stabilizing Selection
Temporal Isolation
Definition
Picture
Chapter 16 ~ Evolution of populations
Variation and gene pools
•Gene pool – consists of _____________________ ____________________
•Genetic variation – 2 main sources
•_______________________
–Change in sequence of DNA
•_______________________
–Occurs during production of gametes
Process of speciation
•As new species evolve, populations become _____________________
_____________________ from each other.
•3 Main Concepts – Behavioral, Geographic, Temporal,
What is Reproductive isolation?
•When members of two populations cannot ____________________________ and produce fertile
offspring….
–Reproductive isolation occurs
•Now have separate ___________________________ __________________________
•Respond to natural selection and genetic drift as different units.
Behavioral Isolation – leads to reproductive isolation
•Very common mechanism used to keep closely related animals from interbreeding
–Include differences in …..
•___________________________ behavior
•___________________________ signals
•___________________________ calls
Geographic Isolation – leads to reproductive isolation
•Two populations separated by _________________________ _________________________
- Rivers
– Mountains
– Bodies of water
•____________________ _____________________ now works separately on both populations
•Apert and Kaibab squirrels
–Separated by Colorado river aprox. 10,000 yrs ago.
__________________________ Isolation – leads to reproductive isolation
•2 or more species reproduce at different _________________
–Leads to speciation because
•Unlikely to _________________________ with each other
•Then may become _________________________ _______________________
Natural Selection on Polygenic Traits
Directional – whole populations range shifts
Stabilizing - whole populations range gets larger
Disruptive – populations range gets disrupted
Testing natural selection in nature
•Natural selection
–Individuals with different traits have different chances of _____________________ during a
environmental event
•Galapagos finches
–When food scarce on island due to drought, finches with largest beaks most
likely to survive – ate shell fish
Rapid Evolution
•Natural selection takes place _____________________ and sometimes very ______________________
–Ex. Galapagos finches
•Due to drought, next generation of finches had larger beaks than did generation before selection had
occurred.
•Finches had evolved rapidly due to ____________________________
__________________________
Speciation in Darwin’s finches
•_________________________ arrive
–Some species foreign to area arrive
•Separation in population
–Some from founding group get _________________________
•Changes in gene pool occur
–Due to ________________________ and _______________________ ___________________
•Reproductive isolation
–Evolved to point that neither population, if came in contact would/could
____________________
•Ecological Competition
–If both populations regroup in certain area, _________________________ for similar food
sources will occur
•Continued Evolution
–Process continues on
Hardy – Weinberger formula
 The Hardy-Weinberg formula allows scientists to determine whether evolution has occurred.
o p2 + 2pq + q2 = 1
p2 = frequency of _________ (homozygous dominant)
2pq = frequency of ___________ (heterozygous)
q2 = frequency of __________(homozygous recessive)
Hardy – Weinberger principle
•5 conditions are required to maintain genetic equilibrium
–Random mating
•Ensures all have equal opportunity to produce offspring and pass on alleles
–_________________________ population
–No movement in or out of population
–No _______________________
–No natural selection
Deer: Predation or
Starvation
Introduction:
In 1970 the deer population of an island forest reserve about 518 square kilometers in size was about
2000 animals. Although the island had excellent vegetation for feeding, the food supply obviously had
limits. Thus the forest management personnel feared that overgrazing might lead to mass starvation.
Since the area was too remote for hunters, the wildlife service decided to bring in natural predators to
control the deer population. It was hoped that natural predation would keep the deer population from
becoming too large and also increase the deer quality (or health), as predators often eliminate the weaker
members of the herd. In 1971, ten wolves were flown into the island.
Procedure:
A. The results of this program are shown in the following table. The Population Change is the number of
deer born minus the number of deer that died during that year. Fill out the last column for each year
(the first has been calculated for you).
( #
-
#
-
#
) = Deer Pop Change
Year
Original
Wolf
Population
Original
Deer
Population
Deer Born
Deer
Dead by Dead by
Population
Predation Starvation
Change
1971
10
2,000
800
400
100
1972
12
2,300
920
480
240
1973
16
2,500
1,000
640
500
1974
22
2,360
944
880
180
1975
28
2,244
996
1,120
26
1976
24
2,094
836
960
2
1977
21
1,968
788
840
0
1978
18
1,916
766
720
0
1979
19
1,962
780
760
0
1980
19
1,982
790
760
0
+300
B. Most biology textbooks describe that predators and prey exist in a balance. This "balance of
nature" hypothesis has been criticized by some scientists because it suggests a relationship
between predators and prey that is good and necessary.
What is your opinion of the balance of nature hypothesis? Would the deer on the island be better off,
worse off, or about the same without the wolves? Defend your position below in paragraph form.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
C. Graph the ORIGINAL DEER and WOLF populations on the graph below. Use one color to show
deer populations and another color to show wolf populations. You may do either a bar graph or a
line graph.
Key (color)
Wolf Deer -
YEAR
Analysis:
1. Describe what happened to the deer and wolf populations between 1971 and 1980.
2. What do you think would have happened to the deer on the island had wolves NOT been introduced?
Peppered Moth Analysis
http://www.techapps.net/interactives/peppermoths.htm
Step 1: Go to website above
Step 2: Click on POLLUTION AND PEPPERED MOTH
Step 3: Click on BIRDS EYE VIEW
Step 4: Read the description of the lab and complete the simulation for both a light forest and dark
forest.
1. Data Table
Percent Dark Moths
Percent Light Moths
Lichen Forest (light)
Sooty Forest (dark)
2. Explain how the color of moths increases or decreases their chances of survival depending on the
environment.
3. 500 light colored moths and 500 dark colored moths are released into a polluted forest. After 2 days
the moths were recaptured, make a prediction about the number of each type of moth that would be
captured.
4. How has the striking change in coloration come about?
5. What underlying law of nature has produced this change? (Use Darwin's theory of evolution and
apply it to what you have learned in this investigation.)
Ch. 15, 16 study guide
1. In an experiment, what variable do “I” change? ___________________________________________
2. In an experiment, what variable is recorded? _____________________________________________
3. In an experiment, what group is used for comparison? ______________________________________
4. In an experiment, what are the factors that “stay the same” called? ____________________________
5. What are two main sources of genetic variation?___________________________________________
6. Define gene pool…___________________________________________________________________
7. Define crossing over…._____________________________________________________________
8. Define polygenic…___________________________________________________________________
9. Define phenotype…__________________________________________________________________
10. Define genotype…___________________________________________________________________
11. List 3 isolating mechanisms that lead to reproductive isolation…______________________________
___________________________________________________________________________________
12. Describe behavior isolation..___________________________________________________________
___________________________________________________________________________________
13. Describe geographic isolation…________________________________________________________
___________________________________________________________________________________
14. Describe temporal isolation…__________________________________________________________
___________________________________________________________________________________
15. Describe reproductive isolation…_______________________________________________________
___________________________________________________________________________________
16. Define rapid evolution….Give example….________________________________________________
___________________________________________________________________________________
17. Define Hardy-Weinberger principal…___________________________________________________
___________________________________________________________________________________
18. What are the 5 conditions required to maintain genetic equilibrium?__________________________
___________________________________________________________________________________
17. Define Natural Selection______________________________________________________________
__________________________________________________________________________________
18. Define Artificial Selection _____________________________________________________________
___________________________________________________________________________________
19. Define Homologous Structures _________________________________________________________
____________________________________________________________________________________
20. What is a vestigial structure? __________________________________________________________
21. What is survival of the fittest mean? ___________________________________________________
___________________________________________________________________________________
22. Label the following picture with the following terms : allele, genes, chromosomes
23. Name and describe what each graph below is showing regarding natural selection on a species…
A – ________________________________________________________________
B – ________________________________________________________________
C – ________________________________________________________________
24. Describe what the graph below is showing.
________________________________________________________________________________________
______________________________________________________________________________________
25. What types of isolating mechanism is influencing the changes seen in the graph?
______________________________________________________________________________________