BIOLOGY 163 EXAM 2 EVOLUTION QUESTIONS AND ANSWERS
What is evolution? - CORRECT ANSWER✅✅A change in the genetic composition of a population (or
species) over time
Claims of Darwin - CORRECT ANSWER✅✅Descent with modification
- species are related to each other
- species change through time (through natural selection)
What must be happening for evolution to occur (3 things) - CORRECT ANSWER✅✅- variation in
characteristics among individuals (new variation is generated by mutation - which is random/no
directionality)
- variation is inherited (ex. genetic basis)
- differential reproduction among individuals (some individuals reproduce more than others)
Chromosomes - CORRECT ANSWER✅✅length of DNA (and proteins), that carry genetic information
Gene (or locus) - CORRECT ANSWER✅✅small region of a chromosome, codes for a particular trait
Allele - CORRECT ANSWER✅✅version of a gene, alleles occur due to mutations that arise during gene
replication
Genotype - CORRECT ANSWER✅✅alleles carried by an individual, usually at a single locus
Phenotype - CORRECT ANSWER✅✅observable properties of an individual, coded by the genotype
Genotype frequency - CORRECT ANSWER✅✅proportion of population that has certain genotype;
Evolution causes this factor to change
Allele or gene frequency - CORRECT ANSWER✅✅proportion of gene copies (alleles) in population;
Evolution causes this factor to change
, How to find the probability of an allele frequency - CORRECT ANSWER✅✅multiply the frequencies of
each allele -- ex. b (0.6) & b (0.6) = 0.36
How to determine allele frequencies after random mating in the next generation? - CORRECT
ANSWER✅✅b = 0.36 + 1/2 (0.48) = 0.6
- add them together
Hardy-Weinberg Equilibrium - CORRECT ANSWER✅✅A population where allele frequencies remain in
the same proportion generation after generation for a particular gene
- This system is predictive; allows us to estimate the relationship in a population between the
frequencies of alleles for a given gene and the frequencies of genotypes formed by those alleles
What type of hypothesis is Hardy-Weinberg equilibrium? - CORRECT ANSWER✅✅- null hypothesis
against which we can compare to see if populations are evolving
- Note: H-W Equilibrium assumes NO EVOLUTION
- changes in allele or genotypic frequency = Evolution
Hardy-Weinberg Equilibrium for allele frequencies - CORRECT ANSWER✅✅p = frequency of B allele
q = frequency of b allele
Then p + q = 1
Hardy-Weinberg Equilibrium for genotype frequencies - CORRECT ANSWER✅✅p^2 = frequency of BB
2pq = frequency of Bb
q^2 = frequency of bb
Then, p^2 + 2pq + q^2 = 1
Steps to completing Hardy-Weinberg Equilibrium problems - CORRECT ANSWER✅✅1. find q^2 by
dividing recessive by total population (ex. q2 = 90/1000 = 0.9)
2. find q by taking square root of q2
What is evolution? - CORRECT ANSWER✅✅A change in the genetic composition of a population (or
species) over time
Claims of Darwin - CORRECT ANSWER✅✅Descent with modification
- species are related to each other
- species change through time (through natural selection)
What must be happening for evolution to occur (3 things) - CORRECT ANSWER✅✅- variation in
characteristics among individuals (new variation is generated by mutation - which is random/no
directionality)
- variation is inherited (ex. genetic basis)
- differential reproduction among individuals (some individuals reproduce more than others)
Chromosomes - CORRECT ANSWER✅✅length of DNA (and proteins), that carry genetic information
Gene (or locus) - CORRECT ANSWER✅✅small region of a chromosome, codes for a particular trait
Allele - CORRECT ANSWER✅✅version of a gene, alleles occur due to mutations that arise during gene
replication
Genotype - CORRECT ANSWER✅✅alleles carried by an individual, usually at a single locus
Phenotype - CORRECT ANSWER✅✅observable properties of an individual, coded by the genotype
Genotype frequency - CORRECT ANSWER✅✅proportion of population that has certain genotype;
Evolution causes this factor to change
Allele or gene frequency - CORRECT ANSWER✅✅proportion of gene copies (alleles) in population;
Evolution causes this factor to change
, How to find the probability of an allele frequency - CORRECT ANSWER✅✅multiply the frequencies of
each allele -- ex. b (0.6) & b (0.6) = 0.36
How to determine allele frequencies after random mating in the next generation? - CORRECT
ANSWER✅✅b = 0.36 + 1/2 (0.48) = 0.6
- add them together
Hardy-Weinberg Equilibrium - CORRECT ANSWER✅✅A population where allele frequencies remain in
the same proportion generation after generation for a particular gene
- This system is predictive; allows us to estimate the relationship in a population between the
frequencies of alleles for a given gene and the frequencies of genotypes formed by those alleles
What type of hypothesis is Hardy-Weinberg equilibrium? - CORRECT ANSWER✅✅- null hypothesis
against which we can compare to see if populations are evolving
- Note: H-W Equilibrium assumes NO EVOLUTION
- changes in allele or genotypic frequency = Evolution
Hardy-Weinberg Equilibrium for allele frequencies - CORRECT ANSWER✅✅p = frequency of B allele
q = frequency of b allele
Then p + q = 1
Hardy-Weinberg Equilibrium for genotype frequencies - CORRECT ANSWER✅✅p^2 = frequency of BB
2pq = frequency of Bb
q^2 = frequency of bb
Then, p^2 + 2pq + q^2 = 1
Steps to completing Hardy-Weinberg Equilibrium problems - CORRECT ANSWER✅✅1. find q^2 by
dividing recessive by total population (ex. q2 = 90/1000 = 0.9)
2. find q by taking square root of q2
