Punnett Squares
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. What is the percent chance of an F2 organism having light green leaves?
A) 25%
B) 50%
C) 75%
D) 0%
A) 25%
On a pedigree, what would the symbol for a heterozygous carrier woman look like?
A) Half filled square
B) Fully colored square
C) Empty circle
D) Half filled circle
D) Half filled circle
In a population of white and brown rats, 16% of the rats have a white coat. Assuming that white coat color is a recessive trait, what percentage of the rats are heterozygous for the color allele?
A. 48%
B. 84%
C. 4%
D. 64%
A) 48%
According to Darwin, the driving force behind evolution is
A. gene mutation
B. natural selection
C. inheritance of acquired traits
D. larger animals eating smaller animals
B) Natural selection
Calculate the final column in the picture provided. These values represent the average number of offspring produced per female of each age class. Round to three decimal places.
Average # of offspring produced per female of each age class = survivorship * fecundity.
Year 0 - 0.000
Year 1 - 0.176
Year 2 - 0.372
Year 3 - 0.464
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. What is the genotypic and phenotypic ratio of the F2 generation?
Genotypic: 1 DD :2 Dd:1 dd
Phenotypic: 3 Dark green: 1 light green
You and your colleagues are constructing a pedigree for a boy with cystic fibrosis, which has an autosomal recessive inheritance pattern. The individual's younger brother has also been diagnosed with cystic fibrosis. How would these brothers be represented in a pedigree, and what would their genotype be?
a. both would be represented as completely shaded squares (aa)
b. both would be represented as completely shaded squares (AA)
c. the older brother would be a shaded square (AA), while the younger brother would be a half shaded square (Aa)
d. Both would be represented as empty squares with the genotype AA for both
a. both would be represented as completely shaded squares (aa)
The definition of a generation is _____.
A) twenty years
B) the average time between a mother's first offspring and her daughter's first offspring
C) the average time between a father's first offspring and his son's first offspring
D) the average time between parents' first offspring and their child's first offspring
E) none of the above
B) the average time between a mother's first offspring and her daughter's first offspring
A gene mutation in a certain flower allows the flower to produce more seeds. The seeds each have the same chance of producing a new plant as do seeds from flowers that do not possess this mutation. It can be expected that:
A. the mutated gene will become more common in the next generation of these flowers
B. the mutation will kill the flowers that don't have the mutation
C. the other plants in the area will develop the same mutation
D. the seeds with the mutation will taste better to animals
A. the mutated gene will become more common in the next generation of these flowers
Calculate the net reproductive rate for the above table, and indicate whether the population is increasing, decreasing, or remaining stable. Why?
R= 1.01
Increasing because R0 is greater than 1
When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?
A) 75%
B) 0%
C) 25%
D) 50%
E) 100%
D) 50%
The pedigree image tracks Duchenne Muscular Dystrophy (DMD) through several generations. DMD is an X-linked recessive trait.
If individuals I-1 and I-2 had another son, what is the chance that he would have DMD?
100%
Which type of survivorship curve implies a species that devotes much of its energy to survival?
Type 1 survivorship curve
Three-spined stickleback fish (Gasterosteus aculeatus) show substantial heritable variation in gill-raker length related to differences in their diets. Longer gill rakers appear to function better for capturing open-water prey, while shorter gill rakers function better for capturing shallow-water prey. Which of the following types of selection is most likely to be found in a large lake (open water in the middle and shallow water around the sides) with a high density of these fish?
A) directional selection
B) stabilizing selection
C) disruptive selection
D) sexual selection
E) none of the above
C) Disruptive selection
Looking at the image, if a disease sweeps across this population, which age class- if it were wiped out by the disease - would affect the population growth the most? Why?
Age class 3 because the average offspring produced per female is highest for this class.
What are all the possible gamete combinations for the following parents involved in the dihybrid cross between a AAbb and AaBb parent?
One parent would produce 4 Ab gametes and the other would produce the following: AB, Ab, aB, ab
The pedigree image tracks Duchenne Muscular Dystrophy (DMD) through several generations. DMD is an X-linked recessive trait.
If individual II-3 has a child with a carrier woman, what is the percent chance that the child will be a daughter with DMD?
25%
To measure the population of lake trout in a 250-hectare lake, 750 individual trout were netted and marked with a fin clip, then returned to the lake. The next week, the lake was netted again, and out of the 350 lake trout that were caught, 65 had fin clips. State which method of estimating population size this scenario describes and calculate the closest lake trout population size to the nearest whole number (round down if necessary). Remember the following formula:
Population Estimate =
(N marked on first survey x N individuals found on second survey) / N marked on second survey
Mark-recapture method
4038 lake trout
What are the 5 basic assumptions that define Hardy-Weinberg equilibrium?
no mutation
random mating
no gene flow
large population size
and no selection
Calculate the per capita growth rate for the population if the generation time is 1.5. Remember that the formula is r= ln(Ro)/g.
r = 0.0066
In rabbits, the homozygous CC is normal, Cc results in deformed legs, and cc results in very short legs. The genotype BB produces black fur, Bb brown fur, and bb white fur. If a cross is made between brown rabbits with deformed legs and white rabbits with deformed legs, what percentage of the offspring would be expected to have deformed legs and white fur?
A) 33%
B) ~66%
C) 50%
D) 100%
E) 25%
E) 25%
In humans, blue eyes are inherited as a recessive autosomal trait and color blindness is an X-linked recessive trait. A woman with blue eyes and normal color vision whose father was color-blind marries a man who also has normal color vision. He has brown eyes but his mother had blue eyes. Which of the following would you expect to be TRUE for their daughters?
A) One-half of their daughters will have normal color vision and brown eyes; one-half of their daughters will have normal color vision and blue eyes.
B) One-half of their daughters will be color-blind and have blue eyes; one-half of their daughters will be color-blind and have brown eyes.
C) Their daughters will all have normal color vision and brown eyes.
D) Their daughters will all have normal color vision and have blue eyes.
E) One-fourth of their daughters will be color-blind and have blue eyes, one-fourth of their daughters will be color-blind and have brown eyes, one-fourth of their daughters
A) One-half of their daughters will have normal color vision and brown eyes; one-half of their daughters will have normal color vision and blue eyes.
In an environment with black and white rocks, there can either be white (homozygous dominant), black (homozygous recessive), and gray (heterozygous) rabbits. Given the environment conditions and the coats of the rabbits, which color(s) would be at the highest advantage for camouflaging against the rocks, and which type of selection does this indicate? Why? Describe what the graph for this would look like.
Black and white rabbits because they directly blend in with the rocks present in the environment. Gray rabbits are more likely to be seen by predators.
This is an example of disruptive selection.
Graph: Selection against the mean/middle phenotype, FOR the extremes. Two humps (at the extremes) with a valley in the middle.
Sickle-cell disease is a category of conditions which is a homozygous recessive condition and produces "sickled" red blood cells, or ones that look crescent shaped. In a population of 5000, how many babies would you expect to have sickle-cell disease, if the frequency of the dominant allele is 0.96 and the population is at Hardy-Weinberg equilibrium?
8 babies would have sickle-cell disease
If the population size right now is 100, calculate the size the population might attain in 2 years. Remember that Nt = No*e^(rt). Round down to the nearest whole number.
No = Initial population
101