Because tundra is defined by its high-latitude location, it cannot occur near the equator regardless of temperature.

On a rocky reef, a sea urchin population follows logistic growth, with per-capita growth rate of 0.4 and a carrying capacity 2000 individuals.   A) If the current population is N0 = 400, compute the number of new individuals added in the next year and the projected population size at N1. (A full credit answer will show any calculations) (6 pts)             B) Managers compare three possible urchin abundances after a cull: N = 200, N = 900, or N = 1600. At which abundance will the population add the most individuals next year under the logistic model? Briefly justify your choice. (2 pts)

Examine the relationship between water buffalo abundance and rainfall in the African Serengeti. What is the best explanation for why buffalo are only present above 500 mm rainfall?

Building on the Habronattus pyrrithrix jumping spider study, researchers now hypothesize that leg color intensity affects male survival by reducing predation, rather than influencing mating success. They design two treatments: Group 1: Males with leg color darkened using non-toxic paint. Group 2: Control males treated with a clear paint of the same chemical base. Spiders are then released into outdoor enclosures containing both females and predators.   A) Write the prediction being tested in this experiment. Identify both the predictor and response variables. (3 pts)   Prediction:       Predictor variable:   Response variable:   B) The paint used to darken legs can change heat absorption and thus body temperature, which could influence survival for reasons unrelated to predation. In one sentence, describe one practical way to control for the temperature effect in the study design. (1 pt)

What drives the rising and sinking of air in the Hadley cell between 0° and 30° latitude?

In the “selfish herd” model, individuals in a group benefit because each reduces its personal predation risk by moving toward the center of the herd.

The solubility of nitrogen gas at 25°C and a nitrogen pressure of 522 mmHg is 4.7 × 10–4 mol/L. What is the value of the Henry’s Law constant in mol/L·atm?

A solution is prepared by adding 40.3 g of Mg(NO3)2 to 127 g of water. Calculate the mole fraction and molality of magnesium nitrate in this solution.

Which of the following gases is expected to have a higher solubility in water than what is predicted using Henry’s law?

Potassium bromide, KBr, crystallizes like NaCl in a face-centered lattice. The ionic radii of K+ and Br– ions are 133 pm and 195 pm, respectively. Assuming that all Br– ions are positioned in the face and corners of the unit cell, while the K+ ions are positioned along the edge alternating between anions, calculate the length of a unit cell edge.