How does the density of wildebeests grazing on Panicum grasses change over time after the peak rain?
a. Wildebeest density is relatively constant throughout the six months following the rain.
b. Wildebeest density reaches its maximum one month after the rain but then decreases to nearly zero about three months after the rain. Six months after the rain, however, the density has increased slightly.
c. Wildebeest density is very low for two months after the rain but then begins to increase until it reaches its maximum at three months. Five months after the rain, however, the density has decreased to nearly zero.
d. Wildebeest density slowly increases after the rain until it reaches a maximum density at about five months and then begins to decrease.
Using evidence from what you know about wildebeests and Panicum, what is a logical explanation for why the wildebeest population spikes when it does? (Hint: Grasses continue to grow after being grazed.)
a. The wildebeest population spikes before the Panicum grass is grazed by zebras and therefore is taller. This provides a greater abundance of food which is important for ruminants who are adapted to consume larger quantities of less nutritious food.
b. The wildebeest population spikes after the Panicum grass has already been grazed by zebras but has had time to regrow to the same height as before zebra grazing occurred. This provides an abundance of nutritious food for the wildebeests who are less efficient at nutrient and protein uptake than zebras.
c. The wildebeest population spikes after the Panicum grass has already been grazed by zebras and therefore is shorter. This allows greater access to the more nutritious parts of the grass and new growth which is important for ruminants who are adapted to consume smaller quantities of food than zebras.
d. The wildebeest population spikes at about the same time as the gazelle population and after the Panicum grass has already been grazed by zebras and therefore is shorter. Since wildebeests and gazelles are both ruminants, they will thrive on grasses of the same height.
How does the gazelle population density change in relation to the changes in the wildebeest population density over time after the peak rain?
a. The density of the gazelle population remains relatively unchanged and does not seem to be impacted by the rise and fall in the density of the wildebeest population.
b. The density of the gazelle population is at its highest three months after the peak rain which coincides with the highest density in the wildebeest population.
c. The density of the gazelle population is low until three months after the peak rain when it begins to steadily increase at the same time as the wildebeest population density is also increasing.
d. The density of the gazelle population is at its highest five months after the peak rain which coincides with a return to a very low density in the wildebeest population.
Using evidence from what you know about gazelles and Panicum, what is a logical explanation for why the gazelle population spikes when it does? (Hint: Grasses continue to grow after being grazed.)
a. The gazelle population spikes after the Panicum grass has already been grazed by zebras and wildebeests and when it is shortest. This allows them better access to the more nutritious lower and new growth and, as ruminants, they can extract more nutrition from a smaller quantity of high-quality grass.
b. The gazelle population spikes after the Panicum grass has been grazed by zebras but before it has been grazed by wildebeests and therefore is shorter. This allows them better access to the more nutritious lower and new growth which is important for ruminants who are adapted to consume smaller quantities of food than zebras.
c. The gazelle population spikes after the Panicum grass has already been grazed by zebras and wildebeests but has had time to regrow to the same height as before any grazing occurred. This provides an abundance of nutritious food for the gazelles who are less efficient at nutrient and protein uptake than zebras and wildebeests.
d. The gazelle population spikes at about the same time as the wildebeest population and after the Panicum grass has already been grazed by zebras and therefore is shorter. Since wildebeests and gazelles are both ruminants, they will both thrive on grasses of the same height.