Modes of Selection

Question 1

A trait cannot evolve by natural selection unless it influences __ and or reproduction

Answer 1

survival

Question 2

Selection: the relationship between fitness and the trait __

Answer 2

value

Question 3

What the __ of the relationship between ___ and trait value looks like is called the __ of ___

Answer 3

shape, fitness, mode of selection

Question 4

Modes of Selection:
1. Directional Selection: selection for a value of a character that is ___ or lower than its current mean value
a. a single phenotype is favored, causing the allele frequency to continuously shift in ___ direction
ONE D BABY

Answer 4

higher, one

Question 5

2. Stabilizing Selection: selection that __ the mean of a character at or near a constant __ value in a population
   a. Highest survival is associated with the __ phenotype
   b. Diminishes phenotypic and genotypic __within a population
   c. Favors the average ___ and reduces __
   THINK BELL CURVE

Answer 5

maintains, intermediate

a. mean
b. variation
c. individuals, extremes

Question 6

3. Disruptive Selection: Inverted Curve
   a. Favors the ___ and largest individuals
   b. Intermediate phenotypes have the lowest ___, while the extremes have the highest fitness (Increased frequencies at the extremes)
   SHAPE OF A U

Answer 6

a. smallest

b. fitness