(Answers to 1 and 2 can be given in either order)

1. Differences in leaf color are heritable

2. Individuals with some leaf color survive, reproduce better than others

3. e.

4. c.

5. Traits subject to strong natural selection lose genetic variation

6. a.

7.

8. c.

9. a.

10. d.

11. a.

12. d.

13. b.

14. b.

15. gene flow

16. c.

17. [(2(30) + 50]/[2(30+50+55)]

18. (40-50)²/50 + (60-40)²/40 + (10-20)²/20

19. d.

20.

(a) Freq.(R) = (0.8) + (1/2)(0.18) = 0.89

(b) let R=p, r=q

rr=0.09 = q² since in zygotes
q = sqrt 0.09 = 0.3
p=1-0.3=0.7

wRR=1, wRr=1, wrr=0.12

wbar=(0.7)²(1) + 2(0.7)(0.3)(1) + (0.3)²(0.12) = 0.49+ 0.42+0.011 = 0.92

Adult genotype frequencies:

rr = 0.011/0.92 = 0.012
Rr = 0.42/0.92 = 0.46

Freq(r) = Freq(rr) + (1/2) Freq(Rr) = 0.012 + (1/2)(0.46) =0.24

Point breakdown: getting r using square root of 0.09: 2 pts.
Getting wbar: 2 pts
Getting adult genotype frequencies once wbar obtained: 1.5 pts
Getting new freq of r:  1.5 pts

(c)

 

21.-23: point breakdown for different parts of essay given in parentheses.

21.
    1. Flowering plants are not more evolutionarily advanced than ferns because each modern species has been evolving for the same amount of time (and each has adaptations to its own environment.) (4)

    2.  Flowers have not evolved to improve the reproduction of the species since traits evolve because they increase the reproduction of the invidivuals who have them, and this may or may not affect reproduction of the species (4)

22. This hierarchical pattern suggests species have traits in common because they have inherited those traits from ancestral species so all descendents of the same ancestral species would inherit traits from that ancestral species and would therefore have traits in common (3); species descended from a distant ancestor (ex: the ancestor to the protostomes) would have the traits (protostome development), and species descended from a more recent ancestor descended from that distant ancestor, such as the insects, would have the insect trait of 6 legs as well as the traits of the more distant ancestor, such as protostome development (3).  Other objects do not necessarily form such a grouping; for example, elements are grouped naturally in a table, with different properties described by rows versus columns; the properties of the rows do not group inside of the properties described by the columns.  So the hierarchical pattern is something that does not have to occur, and since it does occur in life, and is predicted by common ancestry, it supports evolution (2)

23.  The two forms of evolution in which the allele fixed depends on initial allele frequency are genetic drift (2) and underdominance (2.)  In both forms, the more common allele is more likely to be fixed (2).
    Genetic drift occurs at random, so allele frequencies fluctuate up and down.  An allele fluctating up and down at random is closer to being lost, so random fluctation is likely to result in its loss; similarly, random fluctuation is more likely to result in fixation of a common allele (3).
    When underdominance occurs, the heterozygote has lowest fitness.  Alleles that are rare are more likely to occur in heterozygotes than in homozygotes.  So when an allele is rare, it occurs more in the heterozygote, and since the heterozygote has lowest fitness and dies out, the rare allele occurring primarily in the heterozygote will be lost.  So rare alleles decline and become lost, leaving the initially common allele fixed within the population (3).