Chapter 6 Chapter Quiz

. The vaquita is a tiny porpoise that lives only in the Gulf of California, near Mexico. In 2017, there were 30 vaquitas left in the world. In 2018, there were 12. Based on this information, it would be most correct to say that the vaquita is

extinct.

extinct in the wild.

locally extinct.

functionally extinct.

. A medium-sized flightless bird has very low population numbers. This species is most likely to go extinct if it lives

on an island.

on a mainland near a coast.

in a tropical rain forest.

in an area away from humans.

. Based on their C and Z values from the species-area relationship formula (S = CA^Z), which area described below is likely largest and has the greatest number of species?

Z= 0.15, C = 1.0

Z = 0.15, C = 0.2

Z = 0.35, C = 1.0

Z = 0.35, C = 0.2

. Two islands, one large (A) and one small (B), are located approximately 20 miles from a mainland. Two other islands, one large (C) and one small (D), are located approximately 100 miles from the nearest mainland. According to the island biogeography model, the equilibrium number of species is likely to be greatest on which island?

Island A

Island B

Island C

Island D

. The Amur leopard is critically endangered; according to the latest population estimate, 84 individuals still exist in the wild. It lives only in temperate forests in the far eastern part of Russia and is threatened by poachers because of its beautiful fur. The Amur leopard risks extinction because of all these factors except

narrow geographic range.

small population size.

island habitat.

hunting or harvesting by people.

. The most important fishery for the Atlantic bluefin tuna is in the Mediterranean Sea. The Atlantic bluefin is highly sought after and brings very high prices because it is used to make sushi. It is subject to overfishing and illegal fishing. Pacific bluefin tuna is found mostly in the northern Pacific Ocean but also migrates to the southern Pacific. It is also overfished and has a very low density of spawning stock. Fishery managers are currently working to sustain Pacific bluefin populations by limiting the number of fishes taken. Based on this information, which tuna species is likely at greatest risk for extinction?

Atlantic bluefin, because it lives in the small Mediterranean Sea rather than in a large ocean

Atlantic bluefin, because it is subject to overfishing and illegal fishing

Pacific bluefin, because its ocean habitat makes it harder to fish illegally

Pacific bluefin, because its populations are so low it must be managed

. When new individuals migrate into a population, the population has a greater chance of survival because

migration is the major method for increasing the size of most populations.

migration will help protect the existing population from environmental disasters.

the new arrivals add genetic diversity, which improves the population’s adaptability.

the new arrivals increase genetic drift, which increases heterozygosity in the population.

. A rare lizard species on an island survives by inbreeding. The same species exists in a single small population on the mainland, where it outbreeds with a very similar species. Which population is most likely to survive?

The inbreeding population, because the surviving alleles are the most fit

The inbreeding population, because the offspring will have lower mortality rates

The outbreeding population, because adding new alleles will increase mating success

The outbreeding population, because outbreeding may result in hybrid vigor

. A bird is a member of a rare species, and its population in a certain area is decreasing. Compared to a bird species with a high population, this species would be most affected by

environmental stochasticity, which affects rare species selectively.

environmental stochasticity, which causes more catastrophic changes.

demographic stochasticity, which causes more unpredictable changes.

demographic stochasticity, which affects large and small populations equally.

. Refer to the graph.

Based on the graph, as the effective population size increases, the population shows

more inbreeding in all populations.

less inbreeding in all populations.

more inbreeding in most endangered populations.

less inbreeding in most endangered populations.

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