Ecology and Evolution: Biology 301 -- Wethey 
Department of Biological Sciences 
University of South Carolina

Selection

Selection coefficient s
 
AA Aa Aa  
p2 2pq q2 zygotes Before Selection
1 1 1-s Survival=fitness
p2 2pq (1-s)q2 adults

  Selection coefficient s=0.5
 
AA Aa aa  
p2 2pq q2 zygotes Before Selection
1 1 1-0.5 survival=fitness
p2 2pq (0.5)q2 adults
Selection coefficient s=0.5
 
AA Aa Aa  
p2 2pq q2 zygotes Before Selection
1 1-s 1 Survival = fitness
p2 (0.5)*2pq q2 Adults
Selection coefficient s=0.5
 
AA Aa aa  
p2 2pq q2 zygotes Before Selection
1-s 1 1-s Survival=fitness
(0.5)p2 2pq 0.5 q2 adults

Kettlewell’s Experimental Study of Peppered Moth: Biston betularia

Industrial Melanism:Rapid spread of melanic (dark) forms of 50 species of Lepidoptera in industrial areas of Britain.

H. D. B. Kettlewell's Experiments to Test:

Methods

Visibility Score. 2 observers

Recorded the minimum distance at which the moths could be seen. The corroborating observer was the famous behaviorist Dr. R. A. Hinde.
 
Distance Visible Score  
> 30 yds -3 Conspicuous
20-30 -2  
10-20 -1  
10 +1  
5 +2  
2 +3 Inconspicuous

 

Distribution of Light & Dark Forms

Birmingham - Industrial
 
Typical 89% conspicuous
Carbonaria 2 % conspicuous

Devon - Rural
 
Typical 0 % conspicuous
Carbonaria 95 % conspicuous

Aviary Experiments

Birds took moths in order of conspicuousness

Mark-Release Recapture Experiments

Field Release - Recapture Results - Birmingham
 
  Carbonaria Typical
Release (marked) 447 137
Captures (total) 651 81
Recapture (marked) 123 18
Percent Recaptured 27.5 13.1

  Inconspicuous     Conspicuous
Visibility Score +3 +2 -2 -3
Percent Survival 62.5 68.8 50 31.2

 

Survival vs conspicuousness - typical males
 
  Inconspicuous     Conspicuous
Visibility Score +3 +2 -2 -3
Percent Survival 53.6 50 52 38

Summary of Kettlewell Results

Changes in Pollution and Moth Distribution 1959-1997

Sir Cyril Clarke's data
 
Year % Carbonaria SO2 in air
1959 93 290
1969 92 100
1979 85 40
1989 30 40
1997 6.5 ??

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