Mastering Biology Ch 13-2
In recessive lethal diseases such as Tay-Sachs disease, carriers have one copy of the normal allele and one copy of the allele for the disease. Carriers are represented in the Hardy-Weinberg formula by __________.
2pq
The presence of freckles is due to a dominant allele. Four percent of the individuals in a particular population lack freckles. Use the Hardy-Weinberg formula to calculate the percentage of individuals in this population who are homozygous dominant for freckles.
64%
In a species of snail, dark-shelled individuals are better hidden from bird predators in the shady forest, while light-shelled individuals are better hidden in well-lit brushy edge areas. If there were no areas of intermediate brightness in this habitat,which type of selection would act on shell color in these snails?
Disruptive selection
Which of the following defines Hardy-Weinberg equilibrium?
a nonevolving population in genetic equilibrium
(CHART) Can you identify which mechanism of evolution is at work in each scenario shown below?
a. gene flow b. natural selection c. natural selection d. genetic drift e. natural selection
(CONCEPT MAP) Can you complete this concept map that reviews some key ideas about evolution?
a. genetic variation b. evolution c. hardy-weinberg equilibrium d. sexual reproduction e. allele frequencies f. genetic drift g. adaptations
True or False. In the example described in the tutorial, the red amoebas survived the catastrophic event, and all future generations of amoebas were red because the red amoebas had a higher reproductive rate than the blue ones
false
The evolution of populations due to chance is
genetic drift
In a population with brown and green alleles for color, genetic drift
has more effect on the evolution of a small population.
Which of the following events could NOT be caused by a population bottleneck?
increased population size
Generation-to-generation change in the allele frequencies in a population is _____.
microevolution
Which one of the following can create new alleles?
mutation
Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct?
Gene flow causes the frequency of the brown allele to increase.
Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection?
Green beetles leave more offspring than brown beetles because they are better at finding food.
What does evolutionary fitness measure?
relative reproductive success
Small lizards have difficulty defending their territory, but large lizards are more likely to be preyed upon by owls. Which type of selection would act on body size in these lizards under these conditions?
Stabilizing selection
According to the Hardy-Weinberg formula, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.
sexual reproduction
Which of the following is an example of natural selection that has been seen in our lifetime?
the evolution of antibiotic-resistant bacteria
If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles,
the frequency of the green allele will increase.
Which of the following is a characteristic of a population at Hardy-Weinberg equilibrium?
the population is not evolving
Which one of the following will prevent significant genetic drift?
The population size is large.
If the frequency of one allele in a population is 0.7, what is the frequency of the alternate allele?
0.30
Which of the following statements about the amoeba population described at the end of the tutorial is true?
It is more vulnerable to extinction due to lack of genetic variation.
