Conceptual
In the Hardy-Weinberg equation, what does 2pq represents?
The frequency of heterozygous individuals in a population.
If, on average, 46% of loci in a species' gene pool are heterozygous, then the average homozygosity of the species should be ______.
54%
Over long periods of time, many cave-dwelling organisms have lost their eyes. Tapeworms
have lost their digestive systems. Whales have lost their hind limbs. How can natural selection
account for these losses?
Under particular circumstances that persisted for long periods, each of these structures
presented greater costs than benefits.
In the Hardy Weinberg Equation, ___+___=1
p+q
A population of rabbits may be brown (the dominant phenotype) or white (the recessive phenotype). Brown rabbits have the genotype BB or Bb. White rabbits have the genotype bb. The frequency of the BB genotype is .35. What is the frequency of the B and b allele?
B= 0.59
b= 0.41
What are some examples of natural selection?
The flu virus is an example of natural selection in action. The virus evolves traits that allow it to evade the immune system and replicate, resulting in new strains of the virus.
What five conditions must be present for a population to be in Hardy-Weinberg equilibrium?
1. Large population
2. No mutations
3. No migration
4. Random mating
5. No natural selection
Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during teenage years. If 9 in 10,000 newborn babies have the disease, what are the expected frequencies of the dominant and recessive alleles according to the Hardy-Weinberg model?
q= 0.0300
p= 0.9700
A population has substantial genetic variation. Under the influence of natural selection, what is the correct sequence of the following events?
1. Well-adapted individuals leave more offspring than do poorly adapted individuals.
2. A change occurs in the environment.
3. Gene pool of the population changes.
4. Poorly adapted individuals have a decreased chance of survivorship.
2,4,1,3
How can the Hardy-Weinberg equations be used to study evolution in a population?
By comparing the observed allele frequencies in a population to the predicted frequencies under Hardy-Weinberg equilibrium, scientists can identify which evolutionary forces are acting on the population and to what extent.
If 98 out of 200 individuals in a population express the recessive phenotype, what percent of the population are heterozygotes?
42%
Describe the effects of natural selection on the frequency of characteristics in a population that leads to changes within the species?
Natural selection increases the frequency of characteristics that make individuals better adapted and decreases the frequency of other characteristics.
What are some examples of situations that could disrupt Hardy-Weinberg equilibrium in a population?
Population bottleneck, founder effect, etc.
In a certain group of rabbits, the presence of yellow fur is the result of a homozygous recessive condition in the biochemical pathway producing hair pigment. If the frequency of the allele for this condition in the biochemical pathway is 0.09, what is the frequency of the dominant allele in this population? (Assume that the population is in Hardy-Weinberg equilibrium and only two alleles are present for this gene)
q= 0.3
p= 0.7
The bacterium Staphylococcus aureus experiences a metabolic cost for the upkeep of antibiotic-resistance genes. What could happen in environments where these antibiotics are missing?
These bacteria could be outcompeted by bacteria that have lost these genes.