Download Genetic Evolution Note Review

Genetic Evolution Note Review
1.
What is DNA for?
2.
What is a gene?
3.
What is a population?
4.
What is the gene pool?
5.
What is the relative frequency of an allele?
6.
How are relative frequencies expressed?
7.
What is evolution in genetic terms?
8.
What are the two sources of genetic variation?
9.
What effect do mutations usually have?
10. What is a beneficial mutation called?
11. Why do siblings always have a slightly different combination of genes?
12. Why are variations important for species to survive environmental change?
13. Why is variation or biodiversity important after a species goes extinct.
14. What happened after dinosaurs when extinct?
15. Why did the population of peppered moths change from light to dark?
16. Which does evolution select- genotype or phenotype?
17. How does a beneficial phenotype change the frequency of alleles?
18. How are deadly (lethal) or harmful alleles passed on in the gene pool?
19. Give an example of a deadly disease that continues to be passed on in the gene pool.
20. What has to happen for a population to evolve?
The diagram above shows the change in population over 30 generations. Assuming that the white trait is dominant (L) and the
dark trait is recessive (l), answer the following questions.
21. Out of the animals that were light in color, 60% were found to be homozygous. What was the genotype of the other light
colored animals?
22. What is the genotype of the dark animals, and what is it’s phenotype?
23. What happened to the number of recessive alleles in the population over the 30 generations?
24. For the change in the frequency of alleles to occur, there was a change in the environment to favor the darker trait. Give an
example of an environmental change that would favor the darker phenotype?
25. In the initial population, having the darker trait put the animal at a sever disadvantage, where very few if any would survive
long enough to reproduce. Why didn’t the dark gene disappear from the population?
26. If one of the animals is homozygous for a lighter color and another is heterozygous (a carrier), does either of them have an
advantage for survival? Explain your answer.
For the following statements, determine if it is true or false? If false, change the underlined word to make it true.
______________27. Evolution occurs when the frequency of alleles remains the same
______________28. All of the possible alleles in the population is the gene flow
______________29. Most mutations have no change on the individual
______________30. Lethal alleles are kept in the gene pool by homozygous individuals
______________31. When a gene pool has 27% dominant alleles and 73% recessive alleles, this is an example of the frequency
of alleles.
______________32. New mutations never occur in the gene pool?
______________33. The genes for dark peppered moths increased in the population when factories started polluting local trees
with soot.
______________34. If there is a major change in the environment, life has a greater chance of evolving with less
biodiversity/variations
______________35. If a baby dies of a lethal recessive disease, the parents must have been homozygous
______________36. Evolution select which individual has the most favorable genotype for survival.
A homozygous black mouse has two alleles for black fur. A heterozygous black mouse has one allele for black fur and one allele
for brown fur. A homozygous brown mouse has two alleles for brown fur.
Each rectangle represents one mouse. Each mouse has two alleles, represented by circles, for fur color. Use these rectangles to
color the alleles for the gene pool of the sample population. Color the alleles for black fur black, and color the alleles for
brown fur brown
Number of Black alleles (circles)_______
Number of Brown alleles (circles)_______
Total number of alleles in the gene pool _______
Calculate the frequency of alleles (%) for the black
and brown trait.
#Black x 100 = _______% Black allele
# total
________% Brown allele
37. For evolution to occur, what must happen to the frequency of alleles in this population?
38. In this gene pool, the black trait outnumbers the brown trait. In thirty years, if the environment changes and the brown trait
becomes easier to see by predators, what should happen to the number of alleles in the gene pool?
39. Why would it not be likely for the grown allele to completely be removed from the population?
40. Currently there are more heterozygous mice than homozygous dominant mice. Do the heterozygous mice have an advantage
for survival over the homozygous dominant mice? Why or why not?