Why is it that mutation, acting alone, has little effect on allele frequency, and therefore evolution? What other factors
will magnify the effect? What will be an ideal response?
ANSWER: If the mutation rate for a gene is known, we can use the Hardy–Weinberg formula to
calculate the new allele frequency resulting from mutations in that gene. Let’s use the
dominant trait achondroplasia as an example. For this calculation, we assume that initially
only homozygous recessive individuals with the genotype dd (normal stature) were present in
the population. We will also assume that mutation has added new mutant (D) alleles to each
generation at the rate of 1X10-5. To change the frequency of the recessive allele (d) from 1.0
(100%) to 0.5 (50%) at this rate of mutation will require 70,000 generations, or 1.4 million
years. Our conclusion in this case is that mutation alone has a minimal impact on the amount
of genetic variation present in a population. In other words, mutation generates all new
alleles, but except for very small populations, drift, migration, and selection are the forces
that change the frequency of alleles in a population.
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Which type of joint can be found between the femur and the pelvis?
a. ball-and-socket joint b. plane joint c. saddle joint d. condyloid joint
You read about how learning preparedness influences the associations that an animal is capable of learning. You want to explore the learning preparedness of hamsters. How might you test the learning preparedness of this species?
A. Train hamsters to navigate a maze to reach a reward. Determine which hamsters are fastest -- thus, are most prepared to learn. B. Train hamsters to navigate a maze to reach a reward. Determine the time of day at which the hamsters are fastest -- thus, most prepared to learn. C. Train hamsters to choose between tunnels to find a reward. Switch the reward tunnel frequently, and determine which hamsters learn the new association the fastest. D. Train hamsters to choose between tunnels to find a reward, and mark the tunnels with different visual, tactile, chemosensory or auditory stimuli to see which associations are learnable. Clarify question: What is the key concept addressed by the question? What type of thinking is required? Gather Content: What do you already know about learning preparedness? What other information is related to the question? Choose Answer: Given what you now know, what information is most likely to produce the correct answer? Reflection on Process: Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
What factor accounts for the small size of most
cells? a. size b. composition c. weight d. surface to volume ratio e. all of these
What was the most significant research finding that resulted from the successful cloning of Dolly?
A. Cloned animals are capable of producing normal offspring. B. The nucleus of a fully-differentiated cell can be reprogrammed to be totipotent. C. Genetic imprinting, which occurs in adult reproductive tissue, can take months for sperm and years for eggs. D. The key to cloning success is to pick a donor cell from very early in development.