# AP Biology HELP!

1. Jul 4, 2010

### GreenPrint

1. The problem statement, all variables and given/known data

Questions 109-111 refer to the map below of the distribution of several populations on the continents of Eurasia and North America. These populations were derived from a common ancestral species. The area enclosed by a given dotted line represents the distribution of the population and the numbers in millions of years refer to the earliest fossils evidence found within the bounded area. Present populations are found only in the shaded areas.

h t t p : / / i m g 7 0 4 . i m a g e s h a c k . u s / i m g 7 0 4 / 9 0 8 0 / 5 9 4 3 3 5 1 2 . p n g

109. The oldest existing population is found at
(A) Q
(B) R
(C) S
(D) T
(E) U

For this question I am unsure as to what exact it means by "...and the numbers in millions of years refer to the earliest fossil evidence found within the bounded area". Does this mean that the smaller numbers are younger or older. The way I read this section the smaller numbers are younger. Is this correct I don't know. This is more have an issue with English, which I seem to have a hard time understanding what exactly that section meant. If the smaller numbers are older then the answer would be T.

Answer is either Q or T I can't tell which...

110. The two existing populations that are apparently the most closely related are
(A) Q and R
(B) Q and S
(C) Q and T
(D) R and U
(E) S and T

I chose E becasue S and T are the only sections that are right next to each other and only differ in value from millions of years by 5. I feel very confident about this answer but just want to make sure.

111. The data indicate which of the following about the area occupied by the original species?
(C) It increased and then decreased.
(D) It decreased and then increased.
(E) it remained relatively stable.

This one was sort of tricky. I want to say C becasue it looks like the section with 30 in it is huge compared to the values with 50 and 5 which lead me to believe that it increased and then decreased...

2. Relevant equations

3. The attempt at a solution

See above thanks

2. Jul 5, 2010

### redpenguin

109. (A) Region Q contains the oldest fossil recorded for the species (50million years).
110. (E) S and T diverged within the shortest period of time (5million years)
111. (C) A key note in the introduction to the question: Present populations are found only in the shaded areas. If we look at the area the population covers at 30million years for instance, and compare it to present day, we see that today there is less than there was 30million years ago. Now, if we compare 50million years to 30million years we see that the population was less when the species was 50million years old than it was at 30million. Therefore, the population increased then decreased *(C).