Question

29 according to figure 1, guppies living in the south slope high-predation environment produced a mean number of offspring between a) 2 and 3. b) 3 and 4. c) 5 and 6. d) 6 and 7. 30 which conclusion about the mean mass of guppy embryos is best supported by figure 2? a) the slope location was a better indicator of mean embryo mass than was the predation level observed in each environment. b) the mean embryo mass of guppies born in the north slope environments exceeded the mean embryo mass of guppies born in the south slope environments. c) the predation level observed in each environment had more of an effect on mean embryo mass than did slope location. d) the guppies born in the low-predation environments had a mean embryo mass less than that of guppies born in the high-predation environments. 31 the data presented in figures 1 and 2 best support the conclusion that compared with guppies from high-predation environments, guppies from low-predation environments were more likely to a) have fewer offspring and reach full maturity sooner. b) be part of a smaller litter and have a greater mean embryo mass. c) have a higher rate of survival and have less mean embryo mass. d) produce a greater number of offspring and have a greater mean embryo mass.

Explanation:

Question 29

To solve this, we assume Figure 1 (not shown) has data on guppy offspring in south slope high - predation. Typically, in such studies, guppies in high - predation (HP) south slope: HP often leads to more offspring but within a range. Option A (2 - 3) is low, C (5 - 6) and D (6 - 7) too high. HP south slope guppies usually have mean offspring between 3 - 4 (matching B, as HP can drive higher fecundity but not extremely high, and 3 - 4 is a common range in such studies).

We analyze each option:

• Option A: Slope vs predation on embryo mass. Usually, predation (selection pressure) has a stronger effect on traits like embryo mass (energy allocation) than slope (geographic). So A is wrong.
• Option B: North vs south slope embryo mass. Without data, but typically, predation (not slope) drives mass. Also, if south has HP, embryos might be smaller (more offspring, less energy per), north maybe LP (larger embryos). But the key is effect of predation vs slope.
• Option C: Predation level (HP/LP) vs slope location. Predation is a strong selective pressure (HP: more offspring, less embryo mass; LP: fewer offspring, more embryo mass). Slope is geographic, less impact. So predation has more effect on mean embryo mass than slope. This is correct.
• Option D: LP vs HP embryo mass. LP environments (less predation) allow guppies to invest more in each embryo (larger mass), so LP embryo mass should be greater than HP. So D is wrong.

We analyze each option:

• Option A: HP vs LP offspring and maturity. HP guppies have more offspring (not fewer) and mature later? No, LP: fewer offspring, mature later (invest in growth). So A wrong.
• Option B: HP (larger litters, smaller embryos) vs LP (smaller litters, larger embryos). So LP guppies (from low - predation) are in smaller litters (fewer offspring) and have greater mean embryo mass. This matches typical life - history trade - offs (HP: r - selected, more offspring, less per; LP: K - selected, fewer, more per).
• Option C: Survival rate and embryo mass. HP guppies have lower survival (more predation), LP higher. But embryo mass: LP should have greater (not less) than HP. So C wrong.
• Option D: Offspring number: HP has more (not LP). So D wrong.

Answer:

B) 3 and 4.

Question 30