Question

can all there be answered please. intro to ecology and evolution

1. Chickadees and titmice are two bird species that are common around campus. In winter, they often forage together in flocks. Members of these flocks make alarm calls when predators, especially hawks, are nearby. Give a plausible hypothesis to explain why these birds make alarm calls that benefit members of another species.

2. A farm pond that's never been fished has 100 fish in it in 2018, which you assume to be the carrying capacity (K) of the pond. If you remove 40 fish at the end of the year, how many fish will be in the pond one year later? Assume that the per-year maximum r for the fish is 0.3.

3. You begin foraging in the field that yields 200 insects/day, so there's 10 birds (including you) in it right now. Now suppose that a big flock of 50 birds just moved into the area. All 60 of you birds will distribute themselves between the forest and field according to the rules of the Ideal Free Distribution. Assuming no new immigrants or emigrants, you can expect to gain ____ insects/day if you choose the field and ____ insects/ day if you choose the forest.

Habitat	Insects produced per day
Field	200
Forest	100

a) 6.67, 3.33

b) 5, 5

c) 20, 2

Answer 1

3.a. We have got 60 birds that distribute themselves between forest and field in the way of "ideal free distribution", that means that 30 birds will go to the forest and the other 30 will go to the field, because there are only 2 options (forest and field), so 60/2 = 30.

On the other hand, we have got 200 insects/ day in field and 100 insects/ day in forest, so:

200/30 = 6.67

100/30 = 3.33