Reading 1 - Summary of Background Research:

Question

The Red Squirrel Project was a field experiment designed to test the importance of the amount of food to the ecology and evolution of red squirrels. In the Yukon, the seed of white spruce cones is a critical food resource for red squirrels. White spruce produces extremely high numbers of cones every 2-6 years with few cones produced in the intervening years. Individual red squirrels were likely to experience both very high and very low levels of food within their lifetime, so scientists had to look for trends. Research performed for almost 30 years has indicated that yearly variation in the abundance of spruce cones had important consequences.

Reading 2 - Summary of Background Research

The southwest Yukon has seen a shift to increasingly warm springs and a slightly drier environment. With red squirrels, the more cones females eat in the fall, the earlier they give birth.

Researchers near Kluane Lake, Canada saw a shift to earlier birthing times over the last 10 years. Birthing time can vary a bit, but the team argues that some of the shift has been narrowed down to a few possible causes.


Your Task

In the questions that follow, you will construct an explanation to determine and then explain factors that lead to changes in the red squirrel population.

Question 1

Scientists in Canada study the availability of the Red Squirrel’s food supply. Food availability is impacting the birth rates of the Red Squirrel, with surprising consequences. Select the text that explains what is unusual about the Red Squirrel’s food supply.

(3 points)
Responses

The Red Squirrel Project was a field experiment designed to test the importance of the amount of food to the ecology and evolution of red squirrels.
The Red Squirrel Project was a field experiment designed to test the importance of the amount of food to the ecology and evolution of red squirrels.

Individual red squirrels were likely to experience both very high and very low levels of food within their lifetime, so scientists had to look for trends.
Individual red squirrels were likely to experience both very high and very low levels of food within their lifetime, so scientists had to look for trends.

Research performed for almost 30 years has indicated that yearly variation in the abundance of spruce cones had important consequences.
Research performed for almost 30 years has indicated that yearly variation in the abundance of spruce cones had important consequences.

In the Yukon, the seed of white spruce cones is a critical food resource for red squirrels.
In the Yukon, the seed of white spruce cones is a critical food resource for red squirrels.

White spruce produces extremely high numbers of cones every 2-6 years with few cones produced in the intervening years.
White spruce produces extremely high numbers of cones every 2-6 years with few cones produced in the intervening years.
Question 2
Question 2

By generation 4, scientists observed that some red squirrels were giving birth an average 2.5 days early. Select the two evolutionary advantages that might give the offspring squirrels.

(2 points)
Responses

A. The offspring would grow up sooner in the season, so they would be larger than their competition.
A. The offspring would grow up sooner in the season, so they would be larger than their competition.

B. The females can have a second litter in the year to increase the competition later in the season.
B. The females can have a second litter in the year to increase the competition later in the season.

C. The offspring are more likely to get eaten by predators later in the season.
C. The offspring are more likely to get eaten by predators later in the season.

D. The offspring can climb better later in the season to get to the pine cones.

Answer 1

Question 1

The text that explains what is unusual about the Red Squirrel’s food supply is:

White spruce produces extremely high numbers of cones every 2-6 years with few cones produced in the intervening years.

This statement highlights the variability in food availability that red squirrels experience, which is a significant ecological factor affecting their population dynamics.

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Question 2

The two evolutionary advantages that might give the offspring squirrels are:

A. The offspring would grow up sooner in the season, so they would be larger than their competition.
B. The females can have a second litter in the year to increase the competition later in the season.

Both of these options suggest potential benefits to early birth, such as increased size and competitive advantage against other offspring.