AH Biology - Unit 2 - KA2(b) - Fitness

What is fitness?

Fitness is a measure of the tendency of some organisms to produce more surviving offspring than competing members of the same species.

What do fitter individuals do?

Fitter individuals survive longer and reproduce more.

What does fitness refer to?

Fitness refers to the contribution made to the gene pool of the next generation by individual genotypes.

What are the two types of fitness?

The two types of fitness are:

• Absolute fitness

• Relative fitness

What is absolute fitness?

Absolute fitness is the ratio between the number of individuals of a particular genotype after selection, to those before selection.

What is the formula for determining absolute fitness?

The formula for determining absolute fitness is:

What does it mean if absolute fitness equals 1?

If absolute fitness equals 1, then the genotype is stable in frequency.

What does it mean if absolute fitness equals more than 1?

If absolute fitness equals more than 1, then the genotype is increasing in frequency.

What does it mean if absolute fitness equals less than 1?

If absolute fitness equals less than 1, then the genotype is decreasing in frequency.

What is relative fitness?

Relative fitness is the ratio of the number of surviving offspring per individual of a particular genotype to the number of surviving offspring per individual of the most successful genotype (the genotype with the greatest absolute fitness)

What is the formula for determining relative fitness?

The formula for determining relative fitness is:

What will the relative fitness of the most successful genotype always equal?

The relative fitness of the most successful genotype will always equal 1.

What will the relative fitness of all other genotypes, apart from the most successful, always equal?

The relative fitness of all other genotypes, apart from the most successful, will always equal less than 1.