Lecture 10: Natural selection in the wild

Question 1

Selective Regimes:

Answer 1

• Directional selection
• stabilising selection
• disruptive selection

Question 2

Directional selection;

Answer 2

• shoting all small

- trait mean value moves

Question 3

Stabilising selection;

Answer 3

• shoot top & bottom (extremes)

- maintains mean trait value

Question 4

disruptive selection:

Answer 4

selection against mean trait value. Population mean stays the same but variance is increased

Question 5

Batsman mimicry;

Answer 5

Model = is distasteful!
mimic = is palatable
e.g. wasps
MIMIC POPULATION MUST BE LOWER THAN MODEL

Question 6

e.g. of Batesian mimicry;

Answer 6

Papilio dardanus

• male looks like original so female know who to make with
• BUT females mimic orignal & lots of other distasteful butterflies
• males are distasteful already

Question 7

Ways for detecting natural selection

Answer 7

-look for correlations between characters & spatial or temporal variation in the environment
-look directly for differences in fitness
ALSO need to know; differences in characters are genetic and due to natural selection

Question 8

fitness;

Answer 8

genetic contribution to subsequent generations

Question 9

How can fitness be measured?

Answer 9

as Lifetime Reproductive Success

Question 10

LRS tree;

Answer 10

LRS - survival (NATURAL SELECTION) 
   \ 
  Reproduction (SS)  --Fertility & fecundity (NATURAL SELECTION) 
         \ 
       no. of mates (SEXUAL SELECTION)