Pond A holds 3 species of algae; Pond B holds 14. A heat wave raises both ponds by 6 degrees Celsius, and several algal species cannot grow in warm water. Which pond is more likely to keep producing food for its consumers, and why?

A bark beetle that attacks only one pine species spreads through three forest plots. The pine grows in all three. The graph shows how many tree species each plot contains. Which plot is most likely to keep most of its canopy cover, and why?

A farm plants one potato variety propagated from a single parent plant, so every plant carries nearly identical alleles. A water mold that infects that variety arrives. Why is the whole field at risk rather than part of it?

Three meadows are surveyed for flowering-plant species, shown in the table. A late frost kills every plant species that flowers before May. Which meadow is most likely to still offer flowers to pollinators in June?

Two coral reefs are damaged by the same storm. Reef X has many coral species that build reef structure; Reef Y has one. Ecologists say Reef X has more functional redundancy. What does that mean for its recovery?

Wolves were removed from a valley. Elk then browsed the young willows along the streams almost to nothing, beavers lost their building material and left, and the songbirds that nested in willow thickets disappeared. What does this show about the wolf?

Prairie dogs were removed from a grassland site. The graph shows the number of vertebrate species recorded there in the years afterward. What does the pattern indicate about the prairie dog's role?

In one tropical forest, fig trees are the only plants bearing fruit through the three driest months. Monkeys, hornbills and fruit bats feed on them then. Predict what happens to the community if the fig trees are logged out.

On a rocky shore, an ecologist removed every sea star from one stretch of rock. Mussels spread across the bare rock and crowded out the other attached species, and the number of species there fell from about 15 to 8. What had the sea star been doing?

An ecologist wants evidence that a species in a bay is a keystone species. Which observation would count as that evidence?

Brown tree snakes reached Guam in cargo after World War II. The island's forest birds had never faced a snake that hunts nests at night, and most of them are now gone from the island. Which cause of biodiversity loss does this describe?

Fertilizer washes off fields into a shallow bay. Algae bloom thickly, then die and are broken down by bacteria. Dissolved oxygen near the bottom falls, and the bay's fish and clam species disappear from that area. Which driver of biodiversity loss is this?

A large woodland was cut by roads and housing into separate blocks; the total wooded area fell by only 12 percent. The graph shows bird species counted in blocks of different size ten years later. Which cause of biodiversity loss does this describe?

Trawlers took cod from the Grand Banks faster than the population could reproduce. Catches collapsed and Canada closed the fishery in 1992; cod numbers there have still not returned to their old levels. Which driver of biodiversity loss is this?

Mean temperature on a mountainside rose about 1.5 degrees Celsius between the two butterfly surveys in the table. Which conclusion do the counts support?

The table gives species counts at three sites in the same region. A long drought kills every plant species that cannot survive low soil moisture. Which site is most likely to keep some plant cover, and on what grounds?

The table shows fish species recorded in three reaches of one river in 2005 and again in 2020. Which reach should managers investigate first, and why?

Two woodlots were surveyed for ground beetles with the same trapping effort. The table gives the individuals caught and the number of species among them. Which statement about the two woodlots is accurate?

A rare orchid is disappearing from a nature reserve. Surveys show a non-native shrub has spread across the reserve and now shades the ground where the orchid grows. Which action addresses the cause of the decline?

Sea turtle hatchlings emerge at night and crawl toward the brightest horizon, which is normally the open sea. On one beach lined with bright hotel lighting, most hatchlings crawl inland and die. Which response would most raise hatchling survival?