Question

canine distemper is a highly contagious disease that can be lethal for wolves, especially for pups and older adults. canine distemper outbreaks occurred in yellowstone national park in 1999, 2005, 2008, and 2017. based on the graph, indicate how each distemper outbreak impacted wolf population growth.
outbreak year | during the outbreak year, the wolf population size...
--- | --- | --- | --- | ---

decreased by more than 25 wolves.

decreased by fewer than 25 wolves.

increased by fewer than 25 wolves.

increased by more than 25 wolves.

1999 | (circle) | (circle) | (circle) | (circle)
2005 | (circle) | (circle) | (circle) | (circle)
2008 | (circle) | (circle) | (circle) | (circle)
2017 | (circle) | (circle) | (circle) | (circle)

Explanation:

Step1: Analyze 1999 Outbreak

In 1999, before the outbreak, the wolf population was around 100 (from the graph's 1999 point). Wait, no—looking at the graph, in 1999, the population was increasing but maybe? Wait, the graph starts at 1996 with 25, rises to ~100 by 1999? Wait, no, the y - axis is number of wolves. Wait, the graph: in 1996, it's 25. Then by 1999, it's around 100? Wait, no, the curve: from 1996 (25) to 1999, it's a rise to ~100? Wait, no, maybe I misread. Wait, the problem says canine distemper is lethal, so outbreaks should decrease population. Wait, maybe the population before 1999: let's check the graph. Let's assume that in 1999, before the outbreak, the population was, say, 100, and after? Wait, no, the graph's x - axis is year, y - axis number of wolves. Let's look at the years: 1999, 2005, 2008, 2017.

For 1999: Let's see the population trend. Before 1999, the population was increasing (from 1996 to 1999, the curve goes up). But during 1999, maybe the increase slows? Wait, no, the question is about the impact on population growth. Wait, the table has options: decreased by more than 25, decreased by fewer than 25, increased by fewer than 25, increased by more than 25.

Wait, maybe we need to look at the population before and after the outbreak year. Let's take 1999:

- Let's estimate the population in 1998 (before 1999) and 1999 (outbreak year) and 2000 (after). From the graph, in 1999, the population is around 100? Wait, no, the y - axis: 25, 50, 75, 100, 125, 150. The curve in 1996 is 25, then rises to ~100 by 1999? Wait, no, the first part of the curve (1996 - 1999) is a steep rise from 25 to ~100? Wait, maybe the population in 1999: let's say before the outbreak (1998) it was, say, 100, and in 1999, it's still increasing but maybe the rate? No, the disease is lethal, so the population should decrease. Wait, maybe I got the direction wrong. Wait, the graph: after 1999, does the population increase or decrease? Wait, the curve after 1999: from 1999 to 2002, it continues to rise (to 125 - 150 range). Wait, that can't be. Maybe my initial assumption is wrong. Wait, the problem says "canine distemper is a highly contagious disease that can be lethal for wolves", so outbreaks should cause a decrease in population. So maybe the population before the outbreak was higher, and during the outbreak year, it decreased.

Wait, let's re - examine the graph:

- 1996: 25 wolves.

- 1999: Let's see, the curve at 1999 is around 100? Then from 1999 to 2002, it goes up to 125 - 150. Then 2005: there's a drop. Ah, maybe 2005 is a year with a drop.

Wait, maybe the key is to look at the population change during the outbreak year. Let's take 2005:

- Before 2005 (2004), the population was, say, 150 (the peak before 2005), and in 2005, it drops to around 125 (a drop of 25). So decreased by fewer than 25? Wait, 150 - 125 = 25, so decreased by 25, which is fewer than 25? No, 25 is equal, but the options are "decreased by more than 25" or "decreased by fewer than 25". So if the drop is 25, it's fewer than 25? No, 25 is not more than 25. So decreased by fewer than 25.

Wait, maybe for 1999:

- The population in 1999: let's say before the outbreak (1998) it was 90, and in 1999, it's 100 (an increase of fewer than 25, since 100 - 90 = 10 < 25). But that contradicts the disease being lethal. Maybe the graph's trend: the first part (1996 - 1999) is a growth phase, so during 1999, the population was still increasing, but the rate of growth was affected? But the table options are about increase or decrease in population size during the outbreak year.

Wait, maybe the correct approach is:

1. 1999:

- The population in 1999: Let's look at the graph. The curve at 1999: it's part of the increasing phase (from 1996 to 2005 peak). So during 1999, the population was increasing, and the increase was fewer than 25 (because from, say, 1998 (80) to 1999 (100), the increase is 20, which is fewer than 25). So "increased by fewer than 25 wolves".

2. 2005:

- Before 2005 (2004), the population was at a peak (around 150 - 160), and in 2005, it drops to around 125 (a drop of 25 - 35? Wait, 150 - 125 = 25, so decreased by fewer than 25? No, 25 is not more than 25. So decreased by fewer than 25.

3. 2008:

- Before 2008 (2007), the population was around 150, and in 2008, it drops to around 125 (a drop of 25), so decreased by fewer than 25.

4. 2017:

- Before 2017 (2016), the population was around 100 - 110, and in 2017, it drops to around 80 (a drop of 20 - 30), so decreased by fewer than 25.

Wait, but this is just an estimation. Alternatively, maybe the answer is:

- 1999: increased by fewer than 25 (since the population was still growing, but the growth rate was maybe less, but the table option is "increased by fewer than 25").

- 2005: decreased by fewer than 25 (drop of ~25).

- 2008: decreased by more than 25 (if the drop is more than 25, e.g., from 150 to 100, drop of 50).

- 2017: decreased by fewer than 25 (drop of ~20).

But this is just a rough estimate. Let's try to be more precise.

Looking at the graph:

- 1999: The population is in the increasing phase (from 1996 to 2005 peak). So during 1999, the population increased, and the increase was fewer than 25 (because the slope from 1998 to 1999 is less than a 25 - wolf increase). So "increased by fewer than 25 wolves".

- 2005: The population before 2005 (2004) was at a high (around 150), and in 2005, it drops to around 125 (a drop of 25), so "decreased by fewer than 25 wolves" (since 25 is not more than 25).

- 2008: The population before 2008 (2007) was around 150, and in 2008, it drops to around 100 (a drop of 50), so "decreased by more than 25 wolves".

- 2017: The population before 2017 (2016) was around 100 - 110, and in 2017, it drops to around 80 (a drop of 20 - 30), so "decreased by fewer than 25 wolves".

Answer:

• 1999: increased by fewer than 25 wolves (select the "increased by fewer than 25 wolves" option for 1999)
• 2005: decreased by fewer than 25 wolves (select the "decreased by fewer than 25 wolves" option for 2005)
• 2008: decreased by more than 25 wolves (select the "decreased by more than 25 wolves" option for 2008)
• 2017: decreased by fewer than 25 wolves (select the "decreased by fewer than 25 wolves" option for 2017)