Part I: The Forces of Evolution Concept Review (Chapter 4 PowerPoint)
1.) How do we define evolution?
2.) What are the four major forces of evolution (list and briefly define each force).
3.) Is there a way to mathematically calculate evolution? If so, how would we do this?
4.) What conditions are needed for a population to be in Hardy-Weinberg Equilibrium?
1.)
2.)
3.)
4.)
5.) What does the p variable represent?
6.) What does the q variable represent?
7.) What does the portion of the equation represent?
8.) What does the 2pq portion of the equation represent?
9.) What does the portion of the equation represent?
Part II: Hardy-Weinberg Practice Problems:
Follow these steps exactly to calculate genotypic frequencies.
1.) Take the number of homozygous recessive individuals and divide by the total number of individuals in the population. For example if there are 10 homozygous recessive individuals recessive in a population of 100, take 10/100 = 0.10
2.) Take the square root of that number to find the value of q.
3.) Take (1 – q ) to find the value of p.
4.) Plug in the value of p and q into the Hardy-Weinberg equation to find the frequencies of homozygous dominant, heterozygous and homozygous recessive.
Practice Problem #1: The allele for dimples (D) is dominant. In a population of 1000 individuals, 200 individuals have no dimples. Determine the frequency of the dominant (p) and recessive (q) allele. How many individuals would you expect to be homozygous dominant (DD), heterozygous (Dd) and homozygous recessive (dd)?
STEP # 1: Find the value of q, then use this value to find the value of p. ** (p + q = 1) **
p = q=
STEP # 2: Plug in the values into the Hardy-Weinberg Equation.** (+ 2pq + = 1)**
Homozygous Dominant = Heterozygous = Homozygous Recessive =
Practice Problem # 2: The allele for free hanging earlobes (E) is dominant over the allele for attached earlobes. In a population of 10,000 individuals, 2,500 have attached earlobes. Determine the frequency of the dominant (p) and recessive (q) allele. How many individuals will be homozygous dominant (EE), heterozygous (Ee) and homozygous recessive (ee)?
STEP # 1: Find the value of q, then use this value to find the value of p. ** (p + q = 1) **
p = q=
STEP # 2: Plug in the values into the Hardy-Weinberg Equation.** (+ 2pq + = 1)**
Homozygous Dominant = Heterozygous = Homozygous Recessive =
Practice Problem # 3: The ability to taste the chemical PTC is controlled by a dominant allele (T). In a population of 5000 individuals, it was determined that 750 of the individuals were unable to taste PTC. Determine the frequency of the dominant (p) and recessive (q) alleles. How many individuals would you expect to be homozygous dominant (TT), heterozygous (Tt) and homozygous recessive (Tt).
STEP # 1: Find the value of q, then use this value to find the value of p. ** (p + q = 1) **
p = q=
STEP # 2: Plug in the values into the Hardy-Weinberg Equation.** (+ 2pq + = 1)**
Homozygous Dominant = Heterozygous = Homozygous Recessive =
Practice Problem # 4: A small group of 100 people decide to isolate themselves from the world and move to a small and remote deserted island. Out of this population, 10 of the individuals have albino skin, which is due to the homozygous recessive condition (aa). Determine the frequency of the dominant (p) and recessive (q) allele? How many individuals would you expect to be homozygous dominant (AA), heterozygous (Aa) and homozygous recessive (aa)?
STEP # 1: Find the value of q, then use this value to find the value of p. ** (p + q = 1) **
p = q=
STEP # 2: Plug in the values into the Hardy-Weinberg Equation. **(+ 2pq + = 1)**
Homozygous Dominant = Heterozygous = Homozygous Recessive =
ANTH 101L Page 1