Question

1. Describe type 2 functional response of moose that eat plants or wolves that eat moose. Include variables on x and y axis and what controls the shape of the curve

2. Not all plants use the same pathway for photosynthesis. Consider a moisture gradient from the arid desert southwest (arizona) through the semi-arid grasslands of the Great Plains (kansas) to the mesic (moist) deciduous forests of the midwest (ohio).

-Where would you expect to see the different kinds of photosynthetic pathways dominating and why?

-Under what conditions would you find a plant having a photosynthetic pathway that might not be the optinum given the environment?

-Be sure to address environmental and physiological factors in your answer.

3. Englemann spruce (Picea engelmannii) is commonly found in contiguous boreal forest habitat of the Cascade Range and the Northern Rocky Mountains from Idaho and Montana through British Columbia. There are isolated populations in the Southern Rocky Mountains in Colorado, Utah, and New Mexico.

-How did the isolated southern populations become established?

-What kinds of habitats might support then in those isolated southern populations?

-What kinds of habitats might support them in contiguous northern populations?

Answer 1

1.- The type 2 functional response states that consumption rate increases along with the prey density, but even when the prey density keeps increasing, the consumption rate decelerates like reaching a maximum and forming a plateau-like behavior in the curve. Let's observe the following image for Moose eating plants:

The prey consumptions increases but then it starts to stabilize and decelarate the speed.

2.-

There 3 different photosynthetic mechanism: C3, C4 and CAM. We expect CAM plants to be dominant in Arizona, C4 in Kansas and C3 in Ohio. That is because of the mositure availability. CAM plants are adapted to the environments with the least water available, they close their stomata during daylight in order to maintain their water reserve; C4 plants are adapted to hot environments that still keep some water amounts, they don't close their stomata but have some specialized cells in the mesophyll to undergo carbon fixation; and finally C3 plants are the typical plant that depends on regular amounts of water, when the temperature is very hot and dry they close their stomata, but that prevents them from intaking CO2, thus leading to photorespiration wich will kill them in a relatively short time period.

In the three environments we can find plants that do not have the optimum photosynthetic mechanism, the environment with the most occurance of this phenomenon would be the mesic decidious forests, we can find there some CAM species and maybe some C4. That is more probable then to find C3 plants in Arizona because, even they are not using the most effective mechanism they still can live there, while the C3 in Arizona have almost no chance to survive and reproduce.

3.- Well, this spruce has actually not really moved and colonized new habitats, it instead has sufered some habitat fragmentations that has created separated populations. Both the habitats in the northern and southern regions have similar conditions due to the mountain chains. These mountains produce high forest environment, with low temperatures even when approaching to the south