1. Chpt. 23 The Evolution of Populations-- Population Genetics
Natural Selection does act on individuals, in that their characteristics affect their chances of survival and their reproductive success.
The evolutionary impact of natural selection is only apparent in tracking how a population of organisms change over time.
Thus, populations, not individuals, evolve. Some characteristics become more common within the overall population while other characteristics decline.

2. Individuals are selected…
Natural Selection does act on individuals, in that their characteristics affect their chances of survival and their reproductive success.
The evolutionary impact of natural selection is only apparent in tracking how a population of organisms change over time.
Thus, populations, not individuals, evolve. Some characteristics become more common within the overall population while other characteristics decline.
Populations evolve

3. Populations evolve Individuals are selected…
Natural Selection does act on individuals, in that their characteristics affect their chances of survival and their reproductive success.
The evolutionary impact of natural selection is only apparent in tracking how a population of organisms change over time.
Thus, populations, not individuals, evolve. Some characteristics become more common within the overall population while other characteristics decline.
Populations evolve

4. Populations = unit of evolution
Natural selection = mechanism of evolution
Gradualism = accumulation of small changes in gene pool over LONG periods of time
Natural Selection does act on individuals, in that their characteristics affect their chances of survival and their reproductive success.
The evolutionary impact of natural selection is only apparent in tracking how a population of organisms change over time.
Thus, populations, not individuals, evolve. Some characteristics become more common within the overall population while other characteristics decline.

5. Hardy-Weinberg Theorem
Hardy Weinberg- nonevolving populations-
Obviously, not common however, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

6. Hardy-Weinberg Theorem
examines the gene structure of a NON-evolving population
Hardy Weinberg- nonevolving populations-
Obviously, not common however, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

7. Hardy-Weinberg Theorem examines the gene structure of a NON-evolving population.
Obviously, this is not common, however, gives a base-line / model NULL HYPOTHESIS for determining if and why populations evolve
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

8. This has no effect on the overall gene pool percentages.
Hardy-Weinberg Theorem even though alleles are shuffled and recombined during meiosis and random fertilization.
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING
This has no effect on the overall gene pool percentages.

9. A a a a A A a A A a A a A
Not SWIMMING pool….
a GENE POOL!!!

10. Hardy-Weinberg Theorem
Gene pool frequencies (percentages) will remain unchanged if no mechanism that can cause evolution to occur acts on a population.
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

11. Hardy-Weinberg Theorem Gene pool frequencies will remain unchanged if:
Mutations are not occurring
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

12. Hardy-Weinberg Theorem Gene pool frequencies will remain unchanged if:
Natural selection is not occurring
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

13. Hardy-Weinberg Theorem Gene pool frequencies will remain unchanged if:
Population is LARGE
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

14. Hardy-Weinberg Theorem Gene pool frequencies will remain unchanged if:
EVERYONE breeds…
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

15. Hardy-Weinberg Theorem Gene pool frequencies will remain unchanged if:
EVERYONE randomly mates…
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

16. Hardy-Weinberg Theorem Gene pool frequencies will remain unchanged if:
EVERYONE produces the same number of offspring
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

17. Hardy-Weinberg Theorem Gene pool frequencies will remain unchanged if:
NOONE migrates in or out of the population… everyone stays
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

18. Hardy-Weinberg Theorem
Yeah, right....
when does THAT happen?
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

19. 5 Agents of evolutionary change:
Mutation
Gene Flow (migration)
Non-random mating
Genetic Drift (same # of offspring)
Selection

20. Hardy-Weinberg Theorem. remember:. H. W. explains:
Hardy-Weinberg Theorem remember: H.W. explains: the frequency of alleles remains constant in a population… unless acted upon by agents OTHER THAN sexual recombination.
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

21. p +q = 1 p2 + 2pq + q2 = 1 Hardy-Weinberg Principle
Mathematical statement about the relative frequency of alleles (genotypes) in a population.
p +q = 1
p2 + 2pq + q2 = 1

22. Hardy-Weinberg Theorem
Frequency of alleles remains constant in a population, unless acted upon by agents OTHER THAN sexual recombination.
Inheritance does not cause changes in allele frequency.
Remember:
Hardy Weinberg- nonevolving populations-
Obviously, not common howecer, it provides baseline for determining how and why populations evolve
Genetic Structure remains constant over generations
Hardy Weinberg=
Frequency of : p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p2+ 2pq+q2 =1
P2 frequency of AA genotype
2pq= frequency of Aa plus aA genotype
q2 =frequency of the aa genotype
IF THE FREQUENCIES DEVIEATE FROM EXPECTED H.W. VALUES, THEN WE KNOW THE POPULATION IS EVOLVING

23. Hardy-Weinberg Principle
p = frequency of dominant allele
p + q = 1

24. Hardy-Weinberg Principle
q = frequency of recessive allele
p + q = 1

25. in most cases, we only know the phenotypic frequencies
Hardy-Weinberg Principle
Mathematical statement about the relative frequency of alleles (genotypes) in a population.
in most cases, we only know the phenotypic frequencies

26. q2 = # of aa individuals Hardy-Weinberg Principle
q2 = frequency of homozygote recessive individuals
q2 = # of aa individuals

27. p2 = # of AA individuals Hardy-Weinberg Principle
p2 = frequency of homozygote dominant individuals
p2 = # of AA individuals

28. p = # of (AA) + 2 (# Aa) Hardy-Weinberg Principle
p = frequency of dominant allele
p = # of (AA) + 2 (# Aa)

29. q = # of (aa) + 2 (# Aa) Hardy-Weinberg Principle
q = frequency of recessive allele
q = # of (aa) + 2 (# Aa)

30. 2pq = # of Aa individuals Hardy-Weinberg Principle
2pq = frequency of heterozygote individuals
2pq = # of Aa individuals

31. Hardy-Weinberg Principle
by comparing genotypic frequencies from one generation to the next, you can learn whether or not evolution has occurred…

32. Hardy-Weinberg Principle
if genotypic frequencies have changed from your original count…
evolution has occurred!

33. Suppose there are 1,000 individuals in a population
Genotype Number Genotypic Frequency AA Aa aa
total

34. Suppose there are 1,000 individuals in a population
Genotypic Frequency
Genotypic frequency = the proportion of a particular genotype found in a population
0.49
0.42
0.09
total 1.00 AA Aa aa

35. Suppose there are 1,000 individuals in a population
Phenotype Number Phenotypic Frequency
dominant
recessive
total

36. Suppose there are 1,000 individuals in a population
Phenotypic Frequency
Phenotypic frequency = the proportion of a particular phenotype found in a population
0.91
0.09
total 1.00

37. Suppose there are 1,000 individuals in a population
Allele Number Allele Frequency A a
total

38. q = Allele frequency q = frequency of recessive allele
However, we do not know how many a’s there are just by looking at phenotype
480
Allele frequency
Pssst…(There are 1,000 copies of the flower color gene in this population of 500 total flowers…)
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
q =

39. q2 = 20/500 Genotypic frequency q2 = frequency of recessive genotype
480
Genotypic frequency
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
q2 = 20/500

40. q2 = .04 Genotypic frequency q2 = frequency of recessive genotype 480
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
q2 = .04

41. q = .04 Allele frequency q = frequency of recessive allele 480
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
q = .04

42. q = .2 Allele frequency q = frequency of recessive allele 480
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
q = .2

43. q = .2 p + q = 1 p + .2 = 1 p = 1 - .2 p = .8 Allele frequency
q = frequency of recessive allele
p = frequency of dominant allele
480
q = .2
Allele frequency
p + q = 1
p + .2 = 1
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
p =
p = .8

44. 480
p = q = .2
Some of the pink flowers will be AA and some will be Aa
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
p2 + 2pq + q2 = 1

45. 480
Some of the pink flowers will be AA and some will be Aa
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
= 1

46. .64 X 500 individuals 320 individuals are AA
480
How many of the pink flowers will be AA and how many will be Aa
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
.64 X 500 individuals
320 individuals are AA

47. .32 X 500 individuals 160 individuals are Aa
480
How many of the pink flowers will be AA and how many will be Aa
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
.32 X 500 individuals
160 individuals are Aa

48. 480
320 are AA
160 are Aa
480 total
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype

49. .8 x .8 = .64 Genetic structure of next generation
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
Genetic structure of next generation

50. .2 x .2 = .04 Genetic structure of next generation
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
Genetic structure of next generation

51. .2 x .8 = .16
.8 x .2 = .16
.32 aA Aa
Lets first look at the frequency of alleles in a population
Hardy Weinberg=
Frequency: p+q=1 p=1-q q=1-p
Genotype frequencies also add up to 1
p(squared) + 2pq+q(squared) =1
P(squared)= frequency of AA genotype
2pq= frequency of Aa plus aA genotype
Q(squared)= frequency of the aa genotype
Genetic structure of next generation

52. p2 + 2pq + q2 = 1 Hardy-Weinberg Principle
Under ideal conditions, the relative allele frequencies are the same in the offspring generation as in the parent generation.
p2 + 2pq + q2 = 1

53. THEN: we know the population is evolving.
IF: frequencies in a population deviate from Hardy-Weinberg (these are set numbers)…
THEN: we know the population is evolving.
Five Causes of Microevolution (generation to generation changes in a population)
1. Genetic drift (changes in a gene pool of a small population based on chance) (reduces genetic variation by fixing alleles to 1)
2. Gene flow
3. Mutation
4. Nonrandom mating
5. Natural selection

54. Weinburg, I keep telling you, I got sick of changing genes!!!
Oh Hardy, why did you quit your job at ABERCROMBIE?

55. change over time is a result of changes in a population’s frequency of genotypes /
genetic
Five Causes of Microevolution (generation to generation changes in a population)
1. Genetic drift (changes in a gene pool of a small population based on chance) (reduces genetic variation by fixing alleles to 1)
2. Gene flow
3. Mutation
4. Nonrandom mating
5. Natural selection

56. How do
we measure?
Five Causes of Microevolution (generation to generation changes in a population)
1. Genetic drift (changes in a gene pool of a small population based on chance) (reduces genetic variation by fixing alleles to 1)
2. Gene flow
3. Mutation
4. Nonrandom mating
5. Natural selection

57. Lets work an
example
Five Causes of Microevolution (generation to generation changes in a population)
1. Genetic drift (changes in a gene pool of a small population based on chance) (reduces genetic variation by fixing alleles to 1)
2. Gene flow
3. Mutation
4. Nonrandom mating
5. Natural selection

58. Lets Hardy!!
What percentage of the human population are carriers for the allele for PKU?
1 out of 10,000 babies are born with this recessive disease
Most of the time you will begin by determining the frequency of the homozygous recessive genotype
Find q2 (frequency of homo recessive)

59. Lets Hardy!! Find q Find p Find pq
What percentage of the human population are carriers for the allele for PKU?
1 out of 10,000 babies are born with this recessive disease
Hint: q2 = 1 / 10,000 (frequency of aa)
Find q Find p Find pq

60. AP Problems Using Hardy-Weinberg
Solve for q2 (% of total)
Solve for q (equation)
Solve for p (1- q)
H-W is always on the national AP Bio exam (but no calculators are allowed).

61. AP Problems Using Hardy-Weinberg
Solve for q2 (% of total)
Solve for q (equation)
Solve for p (1- q)
H-W is always on the national AP Bio exam (but no calculators are allowed).

62. AP Problems Using Hardy-Weinberg
Solve for q2 (% of total)
Solve for q (equation)
Solve for p (1- q)
H-W is always on the national AP Bio exam (but no calculators are allowed).

63. AP Problems Using Hardy-Weinberg
Solve for q2 (% of total)
Solve for q (equation)
Solve for p (1- q)
H-W is always on the national AP Bio exam (but no calculators are allowed)

64. AP Problems Using Hardy-Weinberg
population: 100 cats
84 black, 16 white
How many of each genotype?
q2 (bb): 16/100 = .16
q (b): √.16 = 0.4
p (B): = 0.6
p2=.36
2pq=.48
q2=.16 BB Bb bb

65. AP Problems Using Hardy-Weinberg
2pq=.48
q2=.16
Assuming H-W equilibrium BB Bb bb
Null hypothesis
p2=.20
2pq=.64
q2=.16 bb Bb BB
Sampled data
How do you explain the data?