36) Theory of selection: selection parameters

Question 1

Selection

Answer 1

• Individuals with advantageous traits tend to be more successful than their peers reproductively
• They give more offspring

Question 2

List the parameters of selection

Answer 2

• SD
• R
• L
• I
• Remount rate

Question 3

Give the types of selection

Answer 3

• Artificial
• Natural
  
  • Ecological
  • Sexual

Question 4

SD

Answer 4

• Selection differential
• The difference of animals selected over the population mean
• Phenotypic difference between mean value of:
  
  • Selected parents
  • Possible parental population

Question 5

R

Answer 5

• Response to selection
• R_generation= h₂ x S

H2 = heritability estimate = S/R

Question 6

Definition of R

Answer 6

Realised average difference between:

• Parent generation
• Next generation

Question 7

L

Answer 7

• Generation interval
• Number weighted average age of the parents at birth

Question 8

I

Answer 8

• Selection pressure/intensity of selection
• Deviation of the selected animals from the herd average

Question 9

Remount rate

Answer 9

• % of progenies that become parents
• Dependent on:
  
  • Reproduction rate
  • Survival rate