1. IV. Variation in Quantitative Traits
V. Selection and Adaptation

2. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions

3. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
- selection: differential reproductive success

4. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
- selection: differential reproductive success
- fitness = reproductive success

5. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
- selection: differential reproductive success
- fitness = reproductive success
- adaptation = a trait or suite of traits that increases reproductive success.

6. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
- selection: differential reproductive success
- fitness = reproductive success
- adaptation = a trait or suite of traits that increases reproductive success.
- exaptation = an adaptation co-opted for a new function. (flight feathers are an exaptation of thermoregulatory feathers, which may be an exaptation of feathers initially adaptive as sexual ornaments).

7. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues

8. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues
- all traits are NOT ‘adaptations’ – “spandrels of San Marco” (Gould and Lewontin) – even if we can envision a function for them.
- some are due to drift in different populations
- some are correlated or linked to adaptive genes

9. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues
C. How do we identify adaptations?

10. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues
C. How do we identify adaptations?
1. Experiment

11. Zonosemata flies (Family Tephritidae) wave their banded wings when threatened. Why?

12. Zonosemata flies (Family Tephritidae) wave their banded wings when threatened. Are they mimicking spiders to deter other predators, mimicking spiders to deter spider predators, or does it have nothing to do with predation? (Waving for courtship?)

14. Housefly..no waving

15. Responses of other preds….

16. ALL EATEN!!!

17. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues
C. How do we identify adaptations?
1. Experiment
2. Observational Studies
- Do desert lizards thermoregulate behaviorally?
can do the physiological relationships between temp and metabolism and activity in the lab…, but do they choose areas that maintain their temp in this range? Go look in an environment with variable temps, and see if choice meets the adaptive expectation.

19. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues
C. How do we identify adaptations?
1. Experiment
2. Observational Studies
3. Comparative Method

20. Some male bats have disproportionately large testis.
And some evolutionary biologists are interested in knowing why.
Is it related to sperm competition and social group size?
- Females in larger groups would have the chance to mate with more males, so there would be greater benefit to producing more sperm…

21. Looks good, but!

22. Data points need to be independent, and these are NOT phylogenetically independent… if we make them so, the data set decays to just two points... Not too conclusive.

23. Compare sister taxa;
When diverge occurs, does the one with a bigger social group have big testes?

24. Compare sister taxa;
When diverge occurs, does the one with a bigger social group have big testes?
Then, slide each relationship to the origin, standardizing the divergence to “0”. Are the endpoints correlated? This controls for phylogenetic correlations.

25. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues
C. How do we identify adaptations?
D. Constraints on the POWER of selection
- physical constraints:
why do flying fish return to water?

26. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues
C. How do we identify adaptations?
D. Constraints on the POWER of selection
- physical constraints:
- contradictory selective pressures
- historical constraints (extant genome, physiology, anatomy, behavior)

27. IV. Variation in Quantitative Traits
V. Selection and Adaptation
A. Definitions
B. Issues
C. How do we identify adaptations?
D. Constraints on the POWER of selection
- physical constraints:
- contradictory selective pressures
- historical constraints (extant genome, physiology, anatomy, behavior)
- lack of genetic variation

28. IV. Variation in Quantitative Traits
V. Selection and Adaptation
VI. Levels of Selection

29. VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.

30. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection

31. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:

32. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
In some organisms, the heterozygote produces a preponderance of one gamete type - this is called "segregation distortion". This gene is at a selective advantage over other genes at this locus. Of course, as it increases in frequency and more organisms are homozygous for it, the differential reproduction drops. However, this can be balanced by the reduced number of gametes these organisms produce.

33. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
In some organisms, the heterozygote produces a preponderance of one gamete type - this is called "segregation distortion". This gene is at a selective advantage over other genes at this locus. Of course, as it increases in frequency and more organisms are homozygous for it, the differential reproduction drops. However, this can be balanced by the reduced number of gametes these organisms produce.
An example is the t-allele in mice. Heterozygotes only produce gametes with the 't' allele - no 'T' gametes.

34. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
In some organisms, the heterozygote produces a preponderance of one gamete type - this is called "segregation distortion". This gene is at a selective advantage over other genes at this locus. Of course, as it increases in frequency and more organisms are homozygous for it, the differential reproduction drops. However, this can be balanced by the reduced number of gametes these organisms produce.
An example is the t-allele in mice. Heterozygotes only produce gametes with the 't' allele - no 'T' gametes. However, the rise in frequency of the 't' allele is balanced at the organismal level by selection against the homozygote - 'tt' is lethal. So, the allele can not increase in frequency and is dependent upon other alleles in the population.

35. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
- Stalk-eyed flies, Cyrtodiopsis dalmanni
(Presgraves, et al.1997).
X(d) meiotic drive element on the X chromosome causes female-biased sex ratios in natural populations of both species.

36. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
- Stalk-eyed flies, Cyrtodiopsis dalmanni
(Presgraves, et al.1997).
X(d) meiotic drive element on the X chromosome causes female-biased sex ratios in natural populations of both species.
spermatid degeneration in male carriers of X(d).

37. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
- Stalk-eyed flies, Cyrtodiopsis dalmanni
(Presgraves, et al.1997).
X(d) meiotic drive element on the X chromosome causes female-biased sex ratios in natural populations of both species.
spermatid degeneration in male carriers of X(d).
balanced by Y-linked and autosomal factors that decrease the intensity of meiotic drive.

38. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
- Stalk-eyed flies, Cyrtodiopsis dalmanni
(Presgraves, et al.1997).
X(d) meiotic drive element on the X chromosome causes female-biased sex ratios in natural populations of both species.
spermatid degeneration in male carriers of X(d).
balanced by Y-linked and autosomal factors that decrease the intensity of meiotic drive.
Even a Y-linked polymorphism for resistance to drive which reduces the intensity and reverses the direction of meiotic drive.

39. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
- Stalk-eyed flies, Cyrtodiopsis dalmanni
(Presgraves, et al.1997).
X(d) meiotic drive element on the X chromosome causes female-biased sex ratios in natural populations of both species.
spermatid degeneration in male carriers of X(d).
balanced by Y-linked and autosomal factors that decrease the intensity of meiotic drive.
Even a Y-linked polymorphism for resistance to drive which reduces the intensity and reverses the direction of meiotic drive.
When paired with X(d), modifying Y chromosomes (Y(m)) cause the transmission of predominantly Y-bearing sperm, and on average, production of 63% male progeny.

40. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements

41. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
these genes replicate themselves independently of cell division... they are gene parasites that make nothing for the cell. yet they increase in frequency relative to other genes in the genome.

42. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
3. 'Selfish' Genes (Richard Dawkins)

43. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
3. 'Selfish' Genes (Richard Dawkins)
- genes are the fundamental replicators

44. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
3. 'Selfish' Genes (Richard Dawkins)
- genes are the fundamental replicators
- genes which confer an advantage, when averaged across other genetic backgrounds, will be selected for. (Analogy of 'crews')

45. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
3. 'Selfish' Genes (Richard Dawkins)
- genes are the fundamental replicators
- genes which confer an advantage, when averaged across other genetic backgrounds, will be selected for. Analogy of 'crews')
- co-adaptive assemblages and non-additive effects are not explained

46. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection

47. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
- some mitochondria in yeast are non-respiring parasites - they survive but don't produce much energy for the cell. They reproduce fast in a cell.

48. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
- some mitochondria in yeast are non-respiring parasites - they survive but don't produce much energy for the cell. They reproduce fast in a cell.
- In small populations of yeast, where selection at the organismal level is weak, there is no cost to the cell to reproducing slowly and the parasitic mitochondria dominate within cells.

49. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
- some mitochondria in yeast are non-respiring parasites - they survive but don't produce much energy for the cell. They reproduce fast in a cell.
- In small populations of yeast, where selection at the organismal level is weak, there is no cost to the cell to reproducing slowly and the parasitic mitochondria dominate within cells.
- In large populations, where aerobic respiration is advantageous at a cellular level, cells with parasites are selected against and the frequency of parasitic mitochondria is reduced.

50. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
- some mitochondria in yeast are non-respiring parasites - they survive but don't produce much energy for the cell. They reproduce fast in a cell.
- In small populations of yeast, where selection at the organismal level is weak, there is no cost to the cell to reproducing slowly and the parasitic mitochondria dominate within cells.
- In large populations, where aerobic respiration is advantageous at a cellular level, cells with parasites are selected against and the frequency of parasitic mitochondria is reduced.
- There is a balance of selection at different levels that must be understood to explain the different frequency of parasitic mitochondria.

51. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection

52. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
- Cancerous Tumour - cell division increases, and the effects may be balanced at a higher level (organism).

53. D. Organism Selection (Darwinian)
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
D. Organism Selection (Darwinian)

54. D. Organism Selection (Darwinian) E. Kin Selection
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
D. Organism Selection (Darwinian)
E. Kin Selection

55. E. Kin Selection (W. D. Hamilton - 1964)
- related individuals that help one another increase their OWN fitness, because their alleles occur within THOSE relatives.

56. E. Kin Selection (W. D. Hamilton - 1964)
- related individuals that help one another increase their OWN fitness, because their alleles occur within THOSE relatives.
- Parental Care

57. E. Kin Selection (W. D. Hamilton - 1964)
- related individuals that help one another increase their OWN fitness, because their alleles occur within THOSE relatives.
- Parental Care
- Helping Behavior by Siblings
Florida Scrub Jay

58. E. Kin Selection (W. D. Hamilton - 1964)
- related individuals that help one another increase their OWN fitness, because their alleles occur within THOSE relatives.
- Parental Care
- Helping Behavior by Siblings
- Sterility and Haplodiploidy

59. D. Organism Selection (Darwinian) E. Kin Selection
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
D. Organism Selection (Darwinian)
E. Kin Selection
F. Group Selection (Wynne-Edwards)

60. F. Group Selection (Wynne-Edwards)
- Can groups replace one another simply by reproductive success??

61. F. Group Selection (Wynne-Edwards)
- Can groups replace one another simply by reproductive success??
- First, it would have to be recognized by it's contradiction with organismal selection.

62. F. Group Selection (Wynne-Edwards)
- Can groups replace one another simply by reproductive success??
- First, it would have to be recognized by it's contradiction with organismal selection.
- (Sacrifice of fitness at the population level with increase at the level of the group).

63. F. Group Selection (Wynne-Edwards)
- Can groups replace one another simply by reproductive success??
- First, it would have to be recognized by it's contradiction with organismal selection.
- (Sacrifice of fitness at the population level with increase at the level of the group).
- Altruism is an obvious example - sacrifice reproduction for benefit of the group... but it usually doesn't work because f(altruism) declines within the pop!

64. D. Organism Selection (Darwinian) E. Kin Selection
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
D. Organism Selection (Darwinian)
E. Kin Selection
F. Group Selection (Wynne-Edwards)
G. Species Selection

65. G. Species Selection

66. G. Species Selection
- Parthenogenesis arises spontaneously, but extinctions are rapid due to lack of variation and Muller's rachet.
Muller's ratchet is the continuous accumulation of mutations in a lineage. In sexual reproduction, since only 1/2 of the genes are passed from each parent, there is a 50% chance that a deleterious new mutation will be purged from the genome just by chance. And also, even if it is expressed, there will be other organisms in the pop that did NOT receive it and have higher fitness. So, selection can purify this sexual population of the deleterious alleles.
But in an asexual lineage, all offspring get the whole genome - even a new deleterious allele. So, there is no way to purge it from the genome.
In fact, in Daphnia pulex, asexual lineages accumulate deleterious amino acid substitutions at 4x the rate of sexual lineages (Paland and Lynch 2006, Science 311: ).

67. G. Species Selection
- Parthenogenesis arises spontaneously, but extinctions are rapid due to lack of variation and Muller's rachet.
So, extinction rates in parthenogenetic lineages are high... and so most lineages that radiate and produe lots of descendant species are sexual.

68. G. Species Selection
- Parthenogenesis arises spontaneously, but extinctions are rapid due to lack of variation and Muller's rachet.
So, extinction rates in parthenogenetic lineages are high... and so most lineages that radiate and produe lots of descendant species are sexual.
- Certain lineage are more likely to speciate (beetles - small, tough, and easily isolated...)

69. G. Species Selection
- Parthenogenesis arises spontaneously, but extinctions are rapid due to lack of variation and Muller's rachet.
So, extinction rates in parthenogenetic lineages are high... and so most lineages that radiate and produe lots of descendant species are sexual.
- Certain lineage are more likely to speciate (beetles - small, tough, and easily isolated...)
SO, as a consequence of survival and speciation rate (reproduction), sexual lineages and also more rapidly speciating lineages will leave more species and replace other lineages that die out over time.